Changes version back to SNAPSHOT

This release just contains some bug-fixes for the TabCompletionHelper's getStringList.

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>net.knarcraft</groupId>
     <artifactId>KnarLib</artifactId>
-    <version>1.1</version>
+    <version>1.2.7-SNAPSHOT</version>
     <packaging>jar</packaging>
 
     <name>KnarLib</name>
@@ -30,7 +30,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-shade-plugin</artifactId>
-                <version>3.2.4</version>
+                <version>3.3.0</version>
                 <executions>
                     <execution>
                         <phase>package</phase>
@@ -39,6 +39,20 @@
                         </goals>
                         <configuration>
                             <createDependencyReducedPom>false</createDependencyReducedPom>
+                            <relocations>
+                                <relocation>
+                                    <pattern>org.jetbrains.annotations</pattern>
+                                    <shadedPattern>net.knarcraft.knarlib.lib.annotations</shadedPattern>
+                                </relocation>
+                            </relocations>
+                            <filters>
+                                <filter>
+                                    <artifact>org.jetbrains:annotations</artifact>
+                                    <includes>
+                                        <include>org/jetbrains/annotations/**</include>
+                                    </includes>
+                                </filter>
+                            </filters>
                         </configuration>
                     </execution>
                 </executions>
@@ -81,7 +95,7 @@
         <dependency>
             <groupId>org.spigotmc</groupId>
             <artifactId>spigot-api</artifactId>
-            <version>1.19.4-R0.1-SNAPSHOT</version>
+            <version>1.20.6-R0.1-SNAPSHOT</version>
             <scope>provided</scope>
         </dependency>
         <dependency>
@@ -90,5 +104,11 @@
             <version>5.9.2</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.jetbrains</groupId>
+            <artifactId>annotations</artifactId>
+            <version>24.0.1</version>
+            <scope>compile</scope>
+        </dependency>
     </dependencies>
 </project>

src/main/java/net/knarcraft/knarlib/formatting/StringFormatter.java

@@ -4,6 +4,9 @@ import net.knarcraft.knarlib.property.ColorConversion;
 import net.knarcraft.knarlib.util.ColorHelper;
 import net.md_5.bungee.api.ChatColor;
 import org.bukkit.command.CommandSender;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.List;
 
 /**
  * A formatter for formatting displayed messages
@@ -15,6 +18,9 @@ public final class StringFormatter {
     private final Translator translator;
     private ChatColor successColor = ChatColor.GREEN;
     private ChatColor errorColor = ChatColor.DARK_RED;
+    private String namePrefix = "[";
+    private String nameSuffix = "]";
+    private ColorConversion colorConversion = ColorConversion.NORMAL;
 
     /**
      * Instantiates a new string formatter
@@ -24,22 +30,45 @@ public final class StringFormatter {
      * @param pluginName <p>The name of the using plugin (used for the message prefix)</p>
      * @param translator <p>The translator to use for translating messages</p>
      */
-    public StringFormatter(String pluginName, Translator translator) {
+    public StringFormatter(@NotNull String pluginName, @NotNull Translator translator) {
         this.pluginName = pluginName;
         this.translator = translator;
     }
 
+    /**
+     * Sets the type of color conversion to use for translated messages
+     *
+     * @param colorConversion <p>The color conversion to use</p>
+     */
+    public void setColorConversion(@NotNull ColorConversion colorConversion) {
+        this.colorConversion = colorConversion;
+    }
+
+    /**
+     * Sets the prefix used in front of the plugin name. Normally just "["
+     *
+     * @param namePrefix <p>The new name prefix</p>
+     */
+    public void setNamePrefix(@NotNull String namePrefix) {
+        this.namePrefix = namePrefix;
+    }
+
+    /**
+     * Sets the suffix used after the plugin name. Normally just "]"
+     *
+     * @param nameSuffix <p>The new name suffix</p>
+     */
+    public void setNameSuffix(@NotNull String nameSuffix) {
+        this.nameSuffix = nameSuffix;
+    }
+
     /**
      * Sets the color to prepend when using displaySuccessMessage
      *
      * @param color <p>The color to use</p>
      */
-    public void setSuccessColor(ChatColor color) {
+    public void setSuccessColor(@NotNull ChatColor color) {
-        if (color != null) {
+        this.successColor = color;
-            this.successColor = color;
-        } else {
-            throw new IllegalArgumentException("Success color cannot be null");
-        }
     }
 
     /**
@@ -47,12 +76,8 @@ public final class StringFormatter {
      *
      * @param color <p>The color to use</p>
      */
-    public void setErrorColor(ChatColor color) {
+    public void setErrorColor(@NotNull ChatColor color) {
-        if (color != null) {
+        this.errorColor = color;
-            this.errorColor = color;
-        } else {
-            throw new IllegalArgumentException("Error color cannot be null");
-        }
     }
 
     /**
@@ -61,8 +86,8 @@ public final class StringFormatter {
      * @param sender  <p>The command sender to display the message to</p>
      * @param message <p>The translatable message to display</p>
      */
-    public void displayNeutralMessage(CommandSender sender, TranslatableMessage message) {
+    public void displayNeutralMessage(@NotNull CommandSender sender, @NotNull TranslatableMessage message) {
-        sender.sendMessage(getFormattedMessage(this.translator.getTranslatedMessage(message)));
+        displayNeutralMessage(sender, this.translator.getTranslatedMessage(message));
     }
 
     /**
@@ -71,7 +96,7 @@ public final class StringFormatter {
      * @param sender  <p>The command sender to display the message to</p>
      * @param message <p>The raw message to display</p>
      */
-    public void displayNeutralMessage(CommandSender sender, String message) {
+    public void displayNeutralMessage(@NotNull CommandSender sender, @NotNull String message) {
         sender.sendMessage(getFormattedMessage(message));
     }
 
@@ -81,8 +106,8 @@ public final class StringFormatter {
      * @param sender  <p>The command sender to display the message to</p>
      * @param message <p>The translatable message to display</p>
      */
-    public void displaySuccessMessage(CommandSender sender, TranslatableMessage message) {
+    public void displaySuccessMessage(@NotNull CommandSender sender, @NotNull TranslatableMessage message) {
-        sender.sendMessage(successColor + getFormattedMessage(this.translator.getTranslatedMessage(message)));
+        displaySuccessMessage(sender, this.translator.getTranslatedMessage(message));
     }
 
     /**
@@ -91,8 +116,12 @@ public final class StringFormatter {
      * @param sender  <p>The command sender to display the message to</p>
      * @param message <p>The raw message to display</p>
      */
-    public void displaySuccessMessage(CommandSender sender, String message) {
+    public void displaySuccessMessage(@NotNull CommandSender sender, @NotNull String message) {
-        sender.sendMessage(successColor + getFormattedMessage(message));
+        if (!this.namePrefix.equals("[") || !this.nameSuffix.equals("]")) {
+            sender.sendMessage(getFormattedMessage(successColor + message));
+        } else {
+            sender.sendMessage(successColor + getFormattedMessage(message));
+        }
     }
 
     /**
@@ -101,8 +130,8 @@ public final class StringFormatter {
      * @param sender  <p>The command sender to display the message to</p>
      * @param message <p>The translatable message to display</p>
      */
-    public void displayErrorMessage(CommandSender sender, TranslatableMessage message) {
+    public void displayErrorMessage(@NotNull CommandSender sender, @NotNull TranslatableMessage message) {
-        sender.sendMessage(errorColor + getFormattedMessage(this.translator.getTranslatedMessage(message)));
+        displayErrorMessage(sender, this.translator.getTranslatedMessage(message));
     }
 
     /**
@@ -111,8 +140,33 @@ public final class StringFormatter {
      * @param sender  <p>The command sender to display the message to</p>
      * @param message <p>The raw message to display</p>
      */
-    public void displayErrorMessage(CommandSender sender, String message) {
+    public void displayErrorMessage(@NotNull CommandSender sender, @NotNull String message) {
-        sender.sendMessage(errorColor + getFormattedMessage(message));
+        if (!this.namePrefix.equals("[") || !this.nameSuffix.equals("]")) {
+            sender.sendMessage(getFormattedMessage(errorColor + message));
+        } else {
+            sender.sendMessage(errorColor + getFormattedMessage(message));
+        }
+    }
+
+    /**
+     * Gets the raw, un-formatted translation of the given translatable message
+     *
+     * @param translatableMessage <p>The message to get the translation of</p>
+     * @return <p>The raw translation</p>
+     */
+    public @NotNull String getUnFormattedMessage(@NotNull TranslatableMessage translatableMessage) {
+        return this.translator.getTranslatedMessage(translatableMessage);
+    }
+
+    /**
+     * Gets the un-formatted translation of the given translatable message, with translated color codes
+     *
+     * @param translatableMessage <p>The message to get the colored translation of</p>
+     * @return <p>The colored raw translation</p>
+     */
+    public @NotNull String getUnFormattedColoredMessage(@NotNull TranslatableMessage translatableMessage) {
+        return ColorHelper.translateColorCodes(this.translator.getTranslatedMessage(translatableMessage),
+                this.colorConversion);
     }
 
     /**
@@ -123,7 +177,8 @@ public final class StringFormatter {
      * @param replacement         <p>The replacement value</p>
      * @return <p>The input string with the placeholder replaced</p>
      */
-    public String replacePlaceholder(TranslatableMessage translatableMessage, String placeholder, String replacement) {
+    public String replacePlaceholder(@NotNull TranslatableMessage translatableMessage, @NotNull String placeholder,
+                                     @NotNull String replacement) {
         return replacePlaceholder(this.translator.getTranslatedMessage(translatableMessage), placeholder, replacement);
     }
 
@@ -135,8 +190,22 @@ public final class StringFormatter {
      * @param replacements        <p>The replacement values</p>
      * @return <p>The input string with placeholders replaced</p>
      */
-    public String replacePlaceholders(TranslatableMessage translatableMessage, String[] placeholders,
+    public String replacePlaceholders(@NotNull TranslatableMessage translatableMessage, @NotNull String[] placeholders,
-                                      String[] replacements) {
+                                      @NotNull String[] replacements) {
+        return replacePlaceholders(this.translator.getTranslatedMessage(translatableMessage), List.of(placeholders),
+                List.of(replacements));
+    }
+
+    /**
+     * Replaces placeholders in a translatable message
+     *
+     * @param translatableMessage <p>The translatable message to replace in</p>
+     * @param placeholders        <p>The placeholders to replace</p>
+     * @param replacements        <p>The replacement values</p>
+     * @return <p>The input string with placeholders replaced</p>
+     */
+    public String replacePlaceholders(@NotNull TranslatableMessage translatableMessage, @NotNull List<String> placeholders,
+                                      @NotNull List<String> replacements) {
         return replacePlaceholders(this.translator.getTranslatedMessage(translatableMessage), placeholders, replacements);
     }
 
@@ -148,7 +217,8 @@ public final class StringFormatter {
      * @param replacement <p>The replacement value</p>
      * @return <p>The input string with the placeholder replaced</p>
      */
-    public static String replacePlaceholder(String input, String placeholder, String replacement) {
+    public static String replacePlaceholder(@NotNull String input, @NotNull String placeholder,
+                                            @NotNull String replacement) {
         return input.replace(placeholder, replacement);
     }
 
@@ -160,9 +230,23 @@ public final class StringFormatter {
      * @param replacements <p>The replacement values</p>
      * @return <p>The input string with placeholders replaced</p>
      */
-    public static String replacePlaceholders(String input, String[] placeholders, String[] replacements) {
+    public static String replacePlaceholders(@NotNull String input, @NotNull String[] placeholders,
-        for (int i = 0; i < Math.min(placeholders.length, replacements.length); i++) {
+                                             @NotNull String[] replacements) {
-            input = replacePlaceholder(input, placeholders[i], replacements[i]);
+        return replacePlaceholders(input, List.of(placeholders), List.of(replacements));
+    }
+
+    /**
+     * Replaces placeholders in a string
+     *
+     * @param input        <p>The input string to replace in</p>
+     * @param placeholders <p>The placeholders to replace</p>
+     * @param replacements <p>The replacement values</p>
+     * @return <p>The input string with placeholders replaced</p>
+     */
+    public static String replacePlaceholders(@NotNull String input, @NotNull List<String> placeholders,
+                                             @NotNull List<String> replacements) {
+        for (int i = 0; i < Math.min(placeholders.size(), replacements.size()); i++) {
+            input = replacePlaceholder(input, placeholders.get(i), replacements.get(i));
         }
         return input;
     }
@@ -173,13 +257,11 @@ public final class StringFormatter {
      * @param message <p>The message to format</p>
      * @return <p>The formatted message</p>
      */
-    private String getFormattedMessage(String message) {
+    private String getFormattedMessage(@NotNull String message) {
-        message = ColorHelper.translateColorCodes(message, ColorConversion.NORMAL);
+        message = ColorHelper.translateColorCodes(message, this.colorConversion);
-        if (this.pluginName == null) {
+        String coloredPrefix = ColorHelper.translateColorCodes(namePrefix + this.pluginName +
-            return message;
+                nameSuffix, this.colorConversion);
-        } else {
+        return coloredPrefix + " " + ChatColor.RESET + message;
-            return "[" + this.pluginName + "] " + ChatColor.RESET + message;
-        }
     }
 
 }

src/main/java/net/knarcraft/knarlib/formatting/StringReplacer.java

@@ -1,5 +1,8 @@
 package net.knarcraft.knarlib.formatting;
 
+import org.jetbrains.annotations.NotNull;
+
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -25,7 +28,7 @@ public final class StringReplacer {
      *
      * @param replacementInput <p>The input string to replace placeholders for</p>
      */
-    public StringReplacer(String replacementInput) {
+    public StringReplacer(@NotNull String replacementInput) {
         this.replacementInput = replacementInput;
     }
 
@@ -35,7 +38,7 @@ public final class StringReplacer {
      * @param placeholder <p>The placeholder to replace</p>
      * @param value       <p>The replacement value</p>
      */
-    public void add(String placeholder, String value) {
+    public void add(@NotNull String placeholder, @NotNull String value) {
         this.replacements.put(placeholder, value);
     }
 
@@ -44,7 +47,7 @@ public final class StringReplacer {
      *
      * @param placeholder <p>The placeholder to remove</p>
      */
-    public void remove(String placeholder) {
+    public void remove(@NotNull String placeholder) {
         this.replacements.remove(placeholder);
     }
 
@@ -55,7 +58,7 @@ public final class StringReplacer {
      *
      * @return <p>The string with placeholders replaced</p>
      */
-    public String replace() {
+    public @NotNull String replace() {
         if (replacementInput == null) {
             throw new IllegalStateException("This method cannot be run without a defined string");
         }
@@ -68,9 +71,9 @@ public final class StringReplacer {
      * @param input <p>The string to replace placeholders in</p>
      * @return <p>The string with placeholders replaced</p>
      */
-    public String replace(String input) {
+    public @NotNull String replace(@NotNull String input) {
-        return StringFormatter.replacePlaceholders(input, replacements.keySet().toArray(new String[0]),
+        return StringFormatter.replacePlaceholders(input, new ArrayList<>(replacements.keySet()),
-                replacements.values().toArray(new String[0]));
+                new ArrayList<>(replacements.values()));
     }
 
 }

src/main/java/net/knarcraft/knarlib/formatting/TimeFormatter.java

@@ -1,5 +1,7 @@
 package net.knarcraft.knarlib.formatting;
 
+import org.jetbrains.annotations.NotNull;
+
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
@@ -28,7 +30,7 @@ public final class TimeFormatter {
      * @param duration   <p>The duration, in seconds, to display</p>
      * @return <p>The string used for displaying this sign's duration</p>
      */
-    public static String getDurationString(Translator translator, long duration) {
+    public static String getDurationString(@NotNull Translator translator, long duration) {
         //Initialize time units once, and only if this method is actually used
         if (sortedUnits == null) {
             initializeUnits(translator);
@@ -76,8 +78,8 @@ public final class TimeFormatter {
      * @param castToInt           <p>Whether to cast the duration to an int</p>
      * @return <p>The formatted duration string</p>
      */
-    private static String formatDurationString(double duration, Translator translator,
+    private static String formatDurationString(double duration, @NotNull Translator translator,
-                                               TranslatableMessage translatableMessage, boolean castToInt) {
+                                               @NotNull TranslatableMessage translatableMessage, boolean castToInt) {
         String durationFormat = translator.getTranslatedMessage(TranslatableTimeUnit.DURATION_FORMAT);
         durationFormat = replacePlaceholder(durationFormat, "{unit}",
                 translator.getTranslatedMessage(translatableMessage));
@@ -88,7 +90,7 @@ public final class TimeFormatter {
     /**
      * Initializes the mapping of available time units for formatting permission sign duration
      */
-    private static void initializeUnits(Translator translator) {
+    private static void initializeUnits(@NotNull Translator translator) {
         //Register each time unit with a registered singular and plural translation
         timeUnits = new HashMap<>();
         registerTimeUnit(translator, 315360000, TranslatableTimeUnit.UNIT_DECADE, TranslatableTimeUnit.UNIT_DECADES);
@@ -102,7 +104,7 @@ public final class TimeFormatter {
                 TranslatableTimeUnit.UNIT_SECONDS);
 
         //As now and seconds are the base units, those must be registered to use getDurationString
-        if (!registeredSeconds || !hasTranslation(translator, TranslatableTimeUnit.UNIT_NOW)) {
+        if (!registeredSeconds || !translator.hasTranslation(TranslatableTimeUnit.UNIT_NOW)) {
             throw new IllegalStateException("A translation is missing for UNIT_SECOND, UNIT_SECONDS or UNIT_NOW");
         }
 
@@ -121,11 +123,12 @@ public final class TimeFormatter {
      * @param plural     <p>The translatable time unit to use for the plural form</p>
      * @return <p>True if the time unit was registered. False if a translation is missing</p>
      */
-    private static boolean registerTimeUnit(Translator translator, double seconds, TranslatableTimeUnit singular,
+    private static boolean registerTimeUnit(@NotNull Translator translator, double seconds,
-                                            TranslatableTimeUnit plural) {
+                                            @NotNull TranslatableTimeUnit singular,
+                                            @NotNull TranslatableTimeUnit plural) {
         String singularTranslation = translator.getTranslatedMessage(singular);
         String pluralTranslation = translator.getTranslatedMessage(plural);
-        if (hasTranslation(translator, singular) && hasTranslation(translator, plural)) {
+        if (translator.hasTranslation(singular) && translator.hasTranslation(plural)) {
             timeUnits.put(seconds, new TranslatableTimeUnit[]{singular, plural});
             return true;
         } else {
@@ -133,16 +136,4 @@ public final class TimeFormatter {
         }
     }
 
-    /**
-     * Checks whether the given translatable message has a registered translation
-     *
-     * @param translator          <p>The translator to check</p>
-     * @param translatableMessage <p>The translatable message to check</p>
-     * @return <p>True if a non-empty translation has been registered</p>
-     */
-    private static boolean hasTranslation(Translator translator, TranslatableMessage translatableMessage) {
-        String translation = translator.getTranslatedMessage(translatableMessage);
-        return translation != null && !translation.isBlank();
-    }
-
 }

src/main/java/net/knarcraft/knarlib/formatting/TranslatableMessage.java

@@ -1,5 +1,7 @@
 package net.knarcraft.knarlib.formatting;
 
+import org.jetbrains.annotations.NotNull;
+
 /**
  * A message which can be translated
  */
@@ -13,7 +15,7 @@ public interface TranslatableMessage {
      *
      * @return <p>The name of this translatable message</p>
      */
-    String name();
+    @NotNull String name();
 
     /**
      * Gets all translatable messages
@@ -22,6 +24,6 @@ public interface TranslatableMessage {
      *
      * @return <p>All translatable messages</p>
      */
-    TranslatableMessage[] getAllMessages();
+    @NotNull TranslatableMessage[] getAllMessages();
 
 }

src/main/java/net/knarcraft/knarlib/formatting/TranslatableTimeUnit.java

@@ -1,5 +1,7 @@
 package net.knarcraft.knarlib.formatting;
 
+import org.jetbrains.annotations.NotNull;
+
 /**
  * An enum containing all translatable time units
  *
@@ -10,7 +12,7 @@ package net.knarcraft.knarlib.formatting;
 public enum TranslatableTimeUnit implements TranslatableMessage {
 
     /**
-     * The format for displaying the exact duration of a blacksmith's cool-down or delay
+     * The format for displaying the duration of something
      */
     DURATION_FORMAT,
 
@@ -101,7 +103,7 @@ public enum TranslatableTimeUnit implements TranslatableMessage {
     ;
 
     @Override
-    public TranslatableMessage[] getAllMessages() {
+    public @NotNull TranslatableMessage[] getAllMessages() {
         return TranslatableTimeUnit.values();
     }
 

src/main/java/net/knarcraft/knarlib/formatting/Translator.java

@@ -5,12 +5,12 @@ import net.knarcraft.knarlib.util.ColorHelper;
 import net.knarcraft.knarlib.util.FileHelper;
 import org.bukkit.Bukkit;
 import org.bukkit.configuration.file.YamlConfiguration;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.io.BufferedReader;
 import java.io.File;
-import java.io.FileInputStream;
 import java.io.FileNotFoundException;
-import java.io.InputStreamReader;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -41,7 +41,7 @@ public final class Translator {
      *
      * @param translatableMessage <p>A translatable message in the category to register</p>
      */
-    public void registerMessageCategory(TranslatableMessage translatableMessage) {
+    public void registerMessageCategory(@NotNull TranslatableMessage translatableMessage) {
         messageCategories.add(translatableMessage);
     }
 
@@ -54,12 +54,8 @@ public final class Translator {
      *
      * @param colorConversion <p>The color conversion to be used</p>
      */
-    public void setColorConversion(ColorConversion colorConversion) {
+    public void setColorConversion(@NotNull ColorConversion colorConversion) {
-        if (colorConversion != null) {
+        this.colorConversion = colorConversion;
-            this.colorConversion = colorConversion;
-        } else {
-            throw new IllegalArgumentException("Color conversion cannot be null");
-        }
     }
 
     /**
@@ -69,7 +65,8 @@ public final class Translator {
      * @param fallbackLanguage <p>The default language to fall back on in the case of missing translations</p>
      * @param selectedLanguage <p>The currently selected language</p>
      */
-    public void loadLanguages(File dataFolder, String fallbackLanguage, String selectedLanguage) {
+    public void loadLanguages(@NotNull File dataFolder, @NotNull String fallbackLanguage,
+                              @NotNull String selectedLanguage) {
         backupTranslatedMessages = loadTranslatedMessages(fallbackLanguage);
         translatedMessages = loadCustomTranslatedMessages(dataFolder, selectedLanguage);
         if (translatedMessages == null) {
@@ -77,13 +74,24 @@ public final class Translator {
         }
     }
 
+    /**
+     * Checks whether the given translatable message has a translation
+     *
+     * @param translatableMessage <p>The translatable message to check</p>
+     * @return <p>True if the message has a translation</p>
+     */
+    public boolean hasTranslation(@NotNull TranslatableMessage translatableMessage) {
+        return backupTranslatedMessages.containsKey(translatableMessage) &&
+                !backupTranslatedMessages.get(translatableMessage).isBlank();
+    }
+
     /**
      * Gets a translated version of the given translatable message
      *
      * @param translatableMessage <p>The message to translate</p>
      * @return <p>The translated message</p>
      */
-    public String getTranslatedMessage(TranslatableMessage translatableMessage) {
+    public @NotNull String getTranslatedMessage(@NotNull TranslatableMessage translatableMessage) {
         if (translatedMessages == null) {
             return "Translated strings not loaded";
         }
@@ -104,7 +112,7 @@ public final class Translator {
      * @param language <p>The language chosen by the user</p>
      * @return <p>A mapping of all strings for the given language</p>
      */
-    public Map<TranslatableMessage, String> loadTranslatedMessages(String language) {
+    public @Nullable Map<TranslatableMessage, String> loadTranslatedMessages(@NotNull String language) {
         try {
             BufferedReader reader = FileHelper.getBufferedReaderForInternalFile("/strings.yml");
             return loadTranslatableMessages(language, reader);
@@ -121,10 +129,8 @@ public final class Translator {
      * @param language   <p>The selected language</p>
      * @return <p>The loaded translated strings, or null if no custom language file exists</p>
      */
-    public Map<TranslatableMessage, String> loadCustomTranslatedMessages(File dataFolder, String language) {
+    public @Nullable Map<TranslatableMessage, String> loadCustomTranslatedMessages(@NotNull File dataFolder,
-        if (dataFolder == null) {
+                                                                                   @NotNull String language) {
-            return null;
-        }
         File strings = new File(dataFolder, "strings.yml");
         if (!strings.exists()) {
             Bukkit.getLogger().log(Level.FINEST, "Strings file not found");
@@ -133,9 +139,9 @@ public final class Translator {
 
         try {
             Bukkit.getLogger().log(Level.INFO, "Loading custom strings...");
-            return loadTranslatableMessages(language, new BufferedReader(new InputStreamReader(
+            return loadTranslatableMessages(language,
-                    new FileInputStream(strings))));
+                    FileHelper.getBufferedReaderFromString(strings.toPath().toString()));
-        } catch (FileNotFoundException e) {
+        } catch (FileNotFoundException exception) {
             Bukkit.getLogger().log(Level.WARNING, "Unable to load custom messages");
             return null;
         }
@@ -148,7 +154,8 @@ public final class Translator {
      * @param reader   <p>The buffered reader to read from</p>
      * @return <p>The loaded translated strings</p>
      */
-    private Map<TranslatableMessage, String> loadTranslatableMessages(String language, BufferedReader reader) {
+    private @NotNull Map<TranslatableMessage, String> loadTranslatableMessages(@NotNull String language,
+                                                                               @NotNull BufferedReader reader) {
         Map<TranslatableMessage, String> translatedMessages = new HashMap<>();
         YamlConfiguration configuration = YamlConfiguration.loadConfiguration(reader);
 

src/main/java/net/knarcraft/knarlib/particle/ParticleConfig.java

@@ -0,0 +1,168 @@
+package net.knarcraft.knarlib.particle;
+
+import org.bukkit.Particle;
+import org.bukkit.configuration.ConfigurationSection;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * A configuration describing a particle
+ */
+@SuppressWarnings("unused")
+public final class ParticleConfig {
+
+    private final ParticleMode particleMode;
+    private final Particle particleType;
+    private final int particleAmount;
+    private final double particleDensity;
+    private final double heightOffset;
+    private final double offsetX;
+    private final double offsetY;
+    private final double offsetZ;
+    private final double extra;
+
+    /**
+     * Instantiates a new particle config
+     *
+     * @param particlesSection <p>The configuration section containing the particle's settings</p>
+     */
+    public ParticleConfig(@NotNull ConfigurationSection particlesSection) {
+        @NotNull Particle particleType;
+        try {
+            particleType = Particle.valueOf(particlesSection.getString("type"));
+        } catch (IllegalArgumentException | NullPointerException exception) {
+            particleType = Particle.ASH;
+        }
+        this.particleType = particleType;
+        this.particleAmount = particlesSection.getInt("amount", 30);
+        this.offsetX = particlesSection.getDouble("offsetX", 0.5);
+        this.offsetY = particlesSection.getDouble("offsetY", 1);
+        this.offsetZ = particlesSection.getDouble("offsetZ", 0.5);
+        this.heightOffset = particlesSection.getDouble("heightOffset", 0.5);
+        this.extra = particlesSection.getDouble("extra", 0);
+        ParticleMode particleMode;
+        try {
+            particleMode = ParticleMode.valueOf(particlesSection.getString("mode"));
+        } catch (IllegalArgumentException | NullPointerException exception) {
+            particleMode = ParticleMode.SINGLE;
+        }
+        this.particleMode = particleMode;
+
+        // Make sure particle density is between 1 (inclusive) and 0 (exclusive)
+        double particleDensity = particlesSection.getDouble("particleDensity", 0.1);
+        if (particleDensity <= 0) {
+            particleDensity = 0.1;
+        } else if (particleDensity > 360) {
+            particleDensity = 360;
+        }
+        this.particleDensity = particleDensity;
+    }
+
+    /**
+     * Instantiates a new particle config
+     *
+     * @param particleMode    <p>The mode to use when spawning the particle</p>
+     * @param particleType    <p>The type of particle to spawn</p>
+     * @param particleAmount  <p>The amount of particles to spawn at once</p>
+     * @param particleDensity <p>The density of the particles, if spawning a shape</p>
+     * @param heightOffset    <p>The offset above the block to spawn the particle</p>
+     * @param offsetX         <p>The x-offset/spread of the spawned particles</p>
+     * @param offsetY         <p>The y-offset/spread of the spawned particles</p>
+     * @param offsetZ         <p>The z-offset/spread of the spawned particles</p>
+     * @param extra           <p>Extra data for the particle. Usage depends on the particle type.</p>
+     */
+    public ParticleConfig(@NotNull ParticleMode particleMode, @NotNull Particle particleType, int particleAmount,
+                          double particleDensity, double heightOffset, double offsetX, double offsetY, double offsetZ,
+                          double extra) {
+        this.particleMode = particleMode;
+        this.particleType = particleType;
+        this.particleAmount = particleAmount;
+        this.particleDensity = particleDensity;
+        this.heightOffset = heightOffset;
+        this.offsetX = offsetX;
+        this.offsetY = offsetY;
+        this.offsetZ = offsetZ;
+        this.extra = extra;
+    }
+
+    /**
+     * The mode to use when drawing/spawning the particle(s)
+     *
+     * @return <p>The particle mode</p>
+     */
+    public @NotNull ParticleMode getParticleMode() {
+        return particleMode;
+    }
+
+    /**
+     * The type of particle to spawn
+     *
+     * @return <p>The particle type</p>
+     */
+    public @NotNull Particle getParticleType() {
+        return particleType;
+    }
+
+    /**
+     * The amount of particles to spawn
+     *
+     * @return <p>The amount of particles</p>
+     */
+    public int getParticleAmount() {
+        return particleAmount;
+    }
+
+    /**
+     * The density of particles to use in shapes closer to 0 causes larger density
+     *
+     * @return <p>The particle density</p>
+     */
+    public double getParticleDensity() {
+        return particleDensity;
+    }
+
+    /**
+     * The number of blocks above the block the particle(s) should spawn
+     *
+     * @return <p>The y-offset</p>
+     */
+    public double getHeightOffset() {
+        return heightOffset;
+    }
+
+    /**
+     * The offset/spread of particles in the x-direction
+     *
+     * @return <p>The x-offset</p>
+     */
+    public double getOffsetX() {
+        return offsetX;
+    }
+
+    /**
+     * The offset/spread of particles in the y-direction
+     *
+     * @return <p>The y-offset</p>
+     */
+    public double getOffsetY() {
+        return offsetY;
+    }
+
+    /**
+     * The offset/spread of particles in the z-direction
+     *
+     * @return <p>The z-offset</p>
+     */
+    public double getOffsetZ() {
+        return offsetZ;
+    }
+
+    /**
+     * The extra value to set for the particle. Exactly what it does depends on the particle.
+     *
+     * @return <p>The particle's extra value</p>
+     */
+    public double getExtra() {
+        return extra;
+    }
+
+}

src/main/java/net/knarcraft/knarlib/particle/ParticleConfigBuilder.java

@@ -0,0 +1,148 @@
+package net.knarcraft.knarlib.particle;
+
+import org.bukkit.Particle;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * A builder for creating particle configurations
+ *
+ * <p>The default behavior will spawn a single particle with no offset or extra data, and density 1.</p>
+ */
+@SuppressWarnings("unused")
+public class ParticleConfigBuilder {
+
+    private final Particle particleType;
+    private ParticleMode particleMode = ParticleMode.SINGLE;
+    private int particleAmount = 1;
+    private double particleDensity = 1;
+    private double heightOffset = 0;
+    private double offsetX = 0;
+    private double offsetY = 0;
+    private double offsetZ = 0;
+    private double extra = 0;
+
+    /**
+     * Instantiates a new particle config builder
+     *
+     * @param particleType <p>The type of particle to spawn</p>
+     */
+    public ParticleConfigBuilder(@NotNull Particle particleType) {
+        this.particleType = particleType;
+    }
+
+    /**
+     * Sets the mode to use when spawning the particles
+     *
+     * @param particleMode <p>The mode to use</p>
+     * @return <p>This particle configuration builder</p>
+     */
+    public @NotNull ParticleConfigBuilder setMode(@NotNull ParticleMode particleMode) {
+        this.particleMode = particleMode;
+        return this;
+    }
+
+    /**
+     * Sets the amount of particles to spawn
+     *
+     * @param particleAmount <p>The number/amount of particles to spawn</p>
+     * @return <p>This particle configuration builder</p>
+     */
+    public @NotNull ParticleConfigBuilder setAmount(int particleAmount) {
+        this.particleAmount = particleAmount;
+        return this;
+    }
+
+    /**
+     * Sets the density of the particles to spawn
+     *
+     * @param particleDensity <p>The new density</p>
+     * @return <p>This particle configuration builder</p>
+     */
+    public @NotNull ParticleConfigBuilder setDensity(double particleDensity) {
+        this.particleDensity = particleDensity;
+        return this;
+    }
+
+    /**
+     * Sets the x,y,z offsets of the spawned particles
+     *
+     * <p>These values control the spread of the spawned particles</p>
+     *
+     * @param offsetX <p>The offset in the x-direction</p>
+     * @param offsetY <p>The offset in the y-direction</p>
+     * @param offsetZ <p>The offset in the z-direction</p>
+     * @return <p>This particle configuration builder</p>
+     */
+    public @NotNull ParticleConfigBuilder setOffsets(double offsetX, double offsetY, double offsetZ) {
+        this.offsetX = offsetX;
+        this.offsetY = offsetY;
+        this.offsetZ = offsetZ;
+        return this;
+    }
+
+    /**
+     * Sets the x offset of the spawned particles
+     *
+     * @param offsetX <p>The offset in the x-direction</p>
+     * @return <p>This particle configuration builder</p>
+     */
+    public @NotNull ParticleConfigBuilder setXOffset(double offsetX) {
+        this.offsetX = offsetX;
+        return this;
+    }
+
+    /**
+     * Sets the y offset of the spawned particles
+     *
+     * @param offsetY <p>The offset in the y-direction</p>
+     * @return <p>This particle configuration builder</p>
+     */
+    public @NotNull ParticleConfigBuilder setYOffset(double offsetY) {
+        this.offsetY = offsetY;
+        return this;
+    }
+
+    /**
+     * Sets the z offset of the spawned particles
+     *
+     * @param offsetZ <p>The offset in the z-direction</p>
+     * @return <p>This particle configuration builder</p>
+     */
+    public @NotNull ParticleConfigBuilder setZOffset(double offsetZ) {
+        this.offsetZ = offsetZ;
+        return this;
+    }
+
+    /**
+     * Sets the extra data for the spawned particles
+     *
+     * @param extra <p>The extra data to set</p>
+     * @return <p>This particle configuration builder</p>
+     */
+    public @NotNull ParticleConfigBuilder setExtra(double extra) {
+        this.extra = extra;
+        return this;
+    }
+
+    /**
+     * Sets the height offset for the spawned particles
+     *
+     * @param heightOffset <p>The height offset to use</p>
+     * @return <p>This particle configuration builder</p>
+     */
+    public @NotNull ParticleConfigBuilder setHeightOffset(double heightOffset) {
+        this.heightOffset = heightOffset;
+        return this;
+    }
+
+    /**
+     * Builds the particle configuration
+     *
+     * @return <p>The built particle configuration</p>
+     */
+    public @NotNull ParticleConfig build() {
+        return new ParticleConfig(particleMode, particleType, particleAmount, particleDensity, heightOffset, offsetX,
+                offsetY, offsetZ, extra);
+    }
+
+}

src/main/java/net/knarcraft/knarlib/particle/ParticleMode.java

@@ -0,0 +1,38 @@
+package net.knarcraft.knarlib.particle;
+
+/**
+ * The mode used for spawning one or more particle(s)
+ */
+public enum ParticleMode {
+
+    /**
+     * Spawns the set amount of particles on a single point in the world
+     */
+    SINGLE,
+
+    /**
+     * Spawns the set amount of particles in a square around the block
+     */
+    SQUARE,
+
+    /**
+     * Spawns the set amount of particles in a circle around the block
+     */
+    CIRCLE,
+
+    /**
+     * Spawns the set amount of particles in a pyramid centered on the block
+     */
+    PYRAMID,
+
+    /**
+     * Spawns the set amount of particles in a sphere centered on the block
+     */
+    SPHERE,
+
+    /**
+     * Spawns the set amount of particles in a cube centered on the block
+     */
+    CUBE,
+
+}

src/main/java/net/knarcraft/knarlib/particle/ParticleSpawner.java

@@ -0,0 +1,142 @@
+package net.knarcraft.knarlib.particle;
+
+import net.knarcraft.knarlib.util.ParticleHelper;
+import org.bukkit.Location;
+import org.bukkit.Material;
+import org.bukkit.World;
+import org.bukkit.block.Block;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Collection;
+import java.util.Map;
+import java.util.UUID;
+import java.util.function.Supplier;
+
+/**
+ * A runnable tasks that spawns particles at the given blocks
+ */
+@SuppressWarnings("unused")
+public final class ParticleSpawner implements Runnable {
+
+    private final ParticleConfig particleConfig;
+    private final Map<Material, ParticleConfig> materialConfigs;
+    private final Collection<Block> blocks;
+    private final Supplier<Collection<Block>> blockSupplier;
+    private final UUID storedCalculationId;
+
+    /**
+     * Instantiates a new particle spawner
+     *
+     * @param particleConfig  <p>The configuration for the particle to spawn</p>
+     * @param materialConfigs <p>Extra particle configurations for specific materials</p>
+     * @param blocks          <p>The blocks to spawn particles on</p>
+     */
+    public ParticleSpawner(@NotNull ParticleConfig particleConfig,
+                           @Nullable Map<Material, ParticleConfig> materialConfigs, @NotNull Collection<Block> blocks) {
+        this.particleConfig = particleConfig;
+        this.materialConfigs = materialConfigs;
+        this.blocks = blocks;
+        this.blockSupplier = null;
+
+        this.storedCalculationId = UUID.randomUUID();
+    }
+
+    /**
+     * Instantiates a new particle spawner
+     *
+     * @param particleConfig  <p>The configuration for the particle to spawn</p>
+     * @param materialConfigs <p>Extra particle configurations for specific materials</p>
+     * @param blockSupplier   <p>The supplier supplying the blocks to spawn particles on</p>
+     */
+    public ParticleSpawner(@NotNull ParticleConfig particleConfig,
+                           @Nullable Map<Material, ParticleConfig> materialConfigs,
+                           @NotNull Supplier<Collection<Block>> blockSupplier) {
+        this.particleConfig = particleConfig;
+        this.materialConfigs = materialConfigs;
+        this.blocks = null;
+        this.blockSupplier = blockSupplier;
+
+        this.storedCalculationId = UUID.randomUUID();
+    }
+
+    /**
+     * Gets the id used for stored calculations
+     *
+     * <p>You should run ParticleHelper.clearStoredCalculations(id) with this id when discarding this particle spawner
+     * to prevent a memory leak.</p>
+     *
+     * @return <p>The id used for stored calculations</p>
+     */
+    public @NotNull UUID getStoredCalculationId() {
+        return this.storedCalculationId;
+    }
+
+    @Override
+    public void run() {
+        // Use the static collection of blocks, or a dynamically changing supplier
+        Collection<Block> blocksToSpawnOn;
+        if (blocks != null) {
+            blocksToSpawnOn = blocks;
+        } else if (blockSupplier != null) {
+            blocksToSpawnOn = blockSupplier.get();
+        } else {
+            throw new RuntimeException("There is a bug in the plugin code. Please contact the developer!");
+        }
+
+        for (Block block : blocksToSpawnOn) {
+            // Ignore blocks in unloaded chunks
+            if (!block.getChunk().isLoaded()) {
+                continue;
+            }
+
+            Location location = block.getLocation().clone();
+            World world = location.getWorld();
+            if (world == null) {
+                continue;
+            }
+
+            spawnParticleForBlock(block, world, location);
+        }
+    }
+
+    /**
+     * Spawns the defined particle for the given block
+     *
+     * @param block    <p>The block to spawn a particle effect for</p>
+     * @param world    <p>The world the block belongs to</p>
+     * @param location <p>A clone of the block's location</p>
+     */
+    private void spawnParticleForBlock(@NotNull Block block, @NotNull World world, @NotNull Location location) {
+        double blockHeight = ParticleHelper.getBlockHeight(block);
+        ParticleConfig activeConfig = getParticleConfig(block.getType());
+
+        switch (activeConfig.getParticleMode()) {
+            case SINGLE -> ParticleHelper.spawnParticle(world, location.clone().add(0.5,
+                    activeConfig.getHeightOffset(), 0.5), activeConfig, blockHeight);
+            case SQUARE -> ParticleHelper.drawSquare(world, location, activeConfig, blockHeight);
+            case CIRCLE -> ParticleHelper.drawCircle(world, location, activeConfig, blockHeight, storedCalculationId);
+            case PYRAMID -> ParticleHelper.drawPyramid(world, location, activeConfig, blockHeight, storedCalculationId);
+            case SPHERE -> ParticleHelper.drawSphere(world, location, activeConfig, blockHeight, storedCalculationId);
+            case CUBE -> ParticleHelper.drawCube(world, location, activeConfig, blockHeight);
+        }
+    }
+
+    /**
+     * Gets the particle config to use for the current block's material
+     *
+     * @param material <p>The material of the block to get a configuration for</p>
+     * @return <p>The particle config to use</p>
+     */
+    private @NotNull ParticleConfig getParticleConfig(@NotNull Material material) {
+        if (this.materialConfigs == null) {
+            return this.particleConfig;
+        }
+        ParticleConfig materialConfig = this.materialConfigs.get(material);
+        if (materialConfig != null) {
+            return materialConfig;
+        }
+        return this.particleConfig;
+    }
+
+}

src/main/java/net/knarcraft/knarlib/particle/ParticleTrailSpawner.java

@@ -0,0 +1,123 @@
+package net.knarcraft.knarlib.particle;
+
+import net.knarcraft.knarlib.util.ParticleHelper;
+import org.bukkit.Bukkit;
+import org.bukkit.Location;
+import org.bukkit.Particle;
+import org.bukkit.World;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Random;
+import java.util.Set;
+import java.util.UUID;
+
+/**
+ * A task for spawning trails behind players
+ */
+@SuppressWarnings("unused")
+public final class ParticleTrailSpawner implements Runnable {
+
+    private final Set<UUID> playersWithTrails = new HashSet<>();
+    private final Map<UUID, Particle> playerParticles = new HashMap<>();
+    private final Random random = new Random();
+    private final Particle particle;
+    private final List<Particle> randomTrailTypes;
+
+    /**
+     * Instantiates a new particle trail spawner
+     *
+     * @param particle         <p>The type of particle used for the trail</p>
+     * @param randomTrailTypes <p>The types of particles to use for random trails</p>
+     */
+    public ParticleTrailSpawner(@NotNull Particle particle, @NotNull List<Particle> randomTrailTypes) {
+        this.particle = particle;
+        this.randomTrailTypes = randomTrailTypes;
+    }
+
+    @Override
+    public void run() {
+        Set<UUID> offlinePlayers = new HashSet<>();
+        for (UUID playerId : playersWithTrails) {
+            // Clear offline players from the list
+            Player player = Bukkit.getPlayer(playerId);
+            if (player == null) {
+                offlinePlayers.add(playerId);
+                continue;
+            }
+
+            // Get the world and location to spawn the particle at
+            Location playerLocation = player.getLocation();
+            World playerWorld = playerLocation.getWorld();
+            if (playerWorld == null) {
+                continue;
+            }
+
+            // Decide on which type of particle to spawn
+            Particle spawnParticle = playerParticles.get(playerId);
+            if (spawnParticle == null) {
+                spawnParticle = this.particle;
+            }
+
+            // Spawn a trail particle
+            ParticleConfig particleConfig = new ParticleConfigBuilder(spawnParticle).build();
+            ParticleHelper.spawnParticle(playerWorld, playerLocation, particleConfig, 0);
+        }
+        playersWithTrails.removeAll(offlinePlayers);
+
+    }
+
+    /**
+     * Removes the trail behind the player with the given id
+     *
+     * @param playerId <p>The id of the player to remove the trail for</p>
+     */
+    public void removeTrail(@NotNull UUID playerId) {
+        this.playersWithTrails.remove(playerId);
+        this.playerParticles.remove(playerId);
+    }
+
+    /**
+     * Adds a random trail behind the player with the given id
+     *
+     * @param playerId <p>The id of the player to add the trail to</p>
+     */
+    public void startRandomTrail(@NotNull UUID playerId) {
+        this.playerParticles.put(playerId, randomParticle());
+        this.playersWithTrails.add(playerId);
+    }
+
+    /**
+     * Adds a trail behind the player with the given id
+     *
+     * @param playerId <p>The id of the player to add the trail to</p>
+     * @param particle <p>The particle to spawn, or null for the particle specified in the constructor</p>
+     */
+    public void startTrail(@NotNull UUID playerId, @Nullable Particle particle) {
+        this.playerParticles.put(playerId, particle);
+        this.playersWithTrails.add(playerId);
+    }
+
+    /**
+     * Gets a random particle from random the specified trail types
+     *
+     * @return <p>A random particle, or EGG_CRACK if no random trail types have been specified</p>
+     */
+    private @NotNull Particle randomParticle() {
+        if (this.randomTrailTypes.isEmpty()) {
+            return Particle.EGG_CRACK;
+        }
+
+        Particle spawnParticle = null;
+        while (spawnParticle == null || spawnParticle.getDataType() != Void.class) {
+            spawnParticle = randomTrailTypes.get(random.nextInt(randomTrailTypes.size()));
+        }
+        return spawnParticle;
+    }
+
+}

src/main/java/net/knarcraft/knarlib/util/ColorHelper.java

@@ -3,6 +3,7 @@ package net.knarcraft.knarlib.util;
 import net.knarcraft.knarlib.property.ColorConversion;
 import net.md_5.bungee.api.ChatColor;
 import org.bukkit.Color;
+import org.jetbrains.annotations.NotNull;
 
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -25,7 +26,7 @@ public final class ColorHelper {
      * @param color <p>The color to invert</p>
      * @return <p>The inverted color</p>
      */
-    public static Color invert(Color color) {
+    public static @NotNull Color invert(@NotNull Color color) {
         return color.setRed(255 - color.getRed()).setGreen(255 - color.getGreen()).setBlue(255 - color.getBlue());
     }
 
@@ -35,7 +36,7 @@ public final class ColorHelper {
      * @param color <p>The color to convert into a chat color</p>
      * @return <p>The resulting chat color</p>
      */
-    public static ChatColor fromColor(Color color) {
+    public static @NotNull ChatColor fromColor(@NotNull Color color) {
         return ChatColor.of(String.format("#%02X%02X%02X", color.getRed(), color.getGreen(), color.getBlue()));
     }
 
@@ -58,7 +59,7 @@ public final class ColorHelper {
      * @param colorConversion <p>The type of color conversion to apply before stripping</p>
      * @return <p>The message without color codes</p>
      */
-    public static String stripColorCodes(String message, ColorConversion colorConversion) {
+    public static @NotNull String stripColorCodes(@NotNull String message, @NotNull ColorConversion colorConversion) {
         return ChatColor.stripColor(translateColorCodes(message, colorConversion));
     }
 
@@ -69,7 +70,7 @@ public final class ColorHelper {
      * @param colorConversion <p>The type of color conversion to apply</p>
      * @return <p>The string with color codes applied</p>
      */
-    public static String translateColorCodes(String message, ColorConversion colorConversion) {
+    public static @NotNull String translateColorCodes(@NotNull String message, @NotNull ColorConversion colorConversion) {
         return switch (colorConversion) {
             case NONE -> message;
             case NORMAL -> ChatColor.translateAlternateColorCodes('&', message);
@@ -85,7 +86,7 @@ public final class ColorHelper {
      * @param onlyRGB <p>Whether to only convert RGB (hexadecimal) color codes. If false, &[a-f0-9] will be converted as well.</p>
      * @return <p>The message with color codes translated</p>
      */
-    private static String translateAllColorCodes(String message, boolean onlyRGB) {
+    private static @NotNull String translateAllColorCodes(@NotNull String message, boolean onlyRGB) {
         if (!onlyRGB) {
             message = ChatColor.translateAlternateColorCodes('&', message);
         }

src/main/java/net/knarcraft/knarlib/util/FileHelper.java

@@ -1,6 +1,8 @@
 package net.knarcraft.knarlib.util;
 
 import net.knarcraft.knarlib.property.ColorConversion;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.io.BufferedReader;
 import java.io.BufferedWriter;
@@ -12,7 +14,9 @@ import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.OutputStreamWriter;
 import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 /**
@@ -33,7 +37,7 @@ public final class FileHelper {
      * @return <p>A buffered read for reading the file</p>
      * @throws FileNotFoundException <p>If unable to get an input stream for the given file</p>
      */
-    public static BufferedReader getBufferedReaderForInternalFile(String file) throws FileNotFoundException {
+    public static @NotNull BufferedReader getBufferedReaderForInternalFile(@NotNull String file) throws FileNotFoundException {
         InputStream inputStream = getInputStreamForInternalFile(file);
         if (inputStream == null) {
             throw new FileNotFoundException("Unable to read the given file");
@@ -50,7 +54,7 @@ public final class FileHelper {
      * @param file <p>The file to read</p>
      * @return <p>An input stream for the file</p>
      */
-    public static InputStream getInputStreamForInternalFile(String file) {
+    public static @Nullable InputStream getInputStreamForInternalFile(@NotNull String file) {
         return FileHelper.class.getResourceAsStream(file);
     }
 
@@ -61,7 +65,7 @@ public final class FileHelper {
      * @return <p>A buffered reader reading the file</p>
      * @throws FileNotFoundException <p>If the given file does not exist</p>
      */
-    public static BufferedReader getBufferedReaderFromString(String file) throws FileNotFoundException {
+    public static @NotNull BufferedReader getBufferedReaderFromString(@NotNull String file) throws FileNotFoundException {
         FileInputStream fileInputStream = new FileInputStream(file);
         return getBufferedReaderFromInputStream(fileInputStream);
     }
@@ -72,19 +76,19 @@ public final class FileHelper {
      * @param inputStream <p>The input stream to read</p>
      * @return <p>A buffered reader reading the input stream</p>
      */
-    public static BufferedReader getBufferedReaderFromInputStream(InputStream inputStream) {
+    public static @NotNull BufferedReader getBufferedReaderFromInputStream(@NotNull InputStream inputStream) {
         InputStreamReader inputStreamReader = new InputStreamReader(inputStream, StandardCharsets.UTF_8);
         return new BufferedReader(inputStreamReader);
     }
 
     /**
-     * Gets a buffered writer from a string pointing to a file
+     * Gets a buffered writer from a buffered reader
      *
      * @param file <p>The file to write to</p>
      * @return <p>A buffered writer writing to the file</p>
      * @throws FileNotFoundException <p>If the file does not exist</p>
      */
-    public static BufferedWriter getBufferedWriterFromString(String file) throws FileNotFoundException {
+    public static @NotNull BufferedWriter getBufferedWriterFromString(@NotNull String file) throws FileNotFoundException {
         FileOutputStream fileOutputStream = new FileOutputStream(file);
         OutputStreamWriter outputStreamWriter = new OutputStreamWriter(fileOutputStream, StandardCharsets.UTF_8);
         return new BufferedWriter(outputStreamWriter);
@@ -99,9 +103,38 @@ public final class FileHelper {
      * @return <p>A map containing the read pairs</p>
      * @throws IOException <p>If unable to read from the stream</p>
      */
-    public static Map<String, String> readKeyValuePairs(BufferedReader bufferedReader, String separator,
+    @NotNull
-                                                        ColorConversion colorConversion) throws IOException {
+    public static Map<String, String> readKeyValuePairs(@NotNull BufferedReader bufferedReader,
+                                                        @NotNull String separator,
+                                                        @NotNull ColorConversion colorConversion) throws IOException {
         Map<String, String> readPairs = new HashMap<>();
+        List<String> lines = readLines(bufferedReader);
+
+        for (String line : lines) {
+            int separatorIndex = line.indexOf(separator);
+            if (separatorIndex == -1) {
+                continue;
+            }
+
+            //Read the line
+            String key = line.substring(0, separatorIndex);
+            String value = ColorHelper.translateColorCodes(line.substring(separatorIndex + 1), colorConversion);
+            readPairs.put(key, value);
+        }
+
+        return readPairs;
+    }
+
+    /**
+     * Reads all lines from a buffered reader
+     *
+     * @param bufferedReader <p>The buffered reader to read</p>
+     * @return <p>A list of the read lines</p>
+     * @throws IOException <p>If unable to read from the stream</p>
+     */
+    @NotNull
+    public static List<String> readLines(@NotNull BufferedReader bufferedReader) throws IOException {
+        List<String> readLines = new ArrayList<>();
 
         String line = bufferedReader.readLine();
         boolean firstLine = true;
@@ -112,22 +145,17 @@ public final class FileHelper {
                 firstLine = false;
             }
             //Split at first separator
-            int separatorIndex = line.indexOf(separator);
+            if (line.isEmpty()) {
-            if (separatorIndex == -1) {
                 line = bufferedReader.readLine();
                 continue;
             }
 
-            //Read the line
+            readLines.add(line);
-            String key = line.substring(0, separatorIndex);
-            String value = ColorHelper.translateColorCodes(line.substring(separatorIndex + 1), colorConversion);
-            readPairs.put(key, value);
-
             line = bufferedReader.readLine();
         }
         bufferedReader.close();
 
-        return readPairs;
+        return readLines;
     }
 
     /**
@@ -136,7 +164,7 @@ public final class FileHelper {
      * @param string <p>The string to remove the BOM from</p>
      * @return <p>A string guaranteed without a BOM</p>
      */
-    private static String removeUTF8BOM(String string) {
+    private static @NotNull String removeUTF8BOM(@NotNull String string) {
         String UTF8_BOM = "\uFEFF";
         if (string.startsWith(UTF8_BOM)) {
             string = string.substring(1);

src/main/java/net/knarcraft/knarlib/util/MaterialHelper.java

@@ -0,0 +1,121 @@
+package net.knarcraft.knarlib.util;
+
+import net.knarcraft.knarlib.formatting.StringFormatter;
+import org.bukkit.Bukkit;
+import org.bukkit.Material;
+import org.bukkit.NamespacedKey;
+import org.bukkit.Tag;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * A helper class for dealing with and parsing materials
+ */
+@SuppressWarnings("unused")
+public final class MaterialHelper {
+
+    private MaterialHelper() {
+
+    }
+
+    /**
+     * Loads the materials specified in the given list
+     *
+     * @param materials <p>The list of material strings to load</p>
+     * @param tagPrefix <p>The prefix differentiating a tag from a material</p>
+     * @param logger    <p>The logger to use for logging parsing errors</p>
+     */
+    public static @NotNull Set<Material> loadMaterialList(@NotNull List<?> materials, @NotNull String tagPrefix,
+                                                          @NotNull Logger logger) {
+        Set<Material> parsedMaterials = new HashSet<>();
+        for (Object value : materials) {
+            if (!(value instanceof String string)) {
+                continue;
+            }
+
+            parsedMaterials.addAll(loadMaterialString(string, tagPrefix, logger));
+        }
+        return parsedMaterials;
+    }
+
+    /**
+     * Parses a string representing a material or a material tag
+     *
+     * @param materialString <p>The material string to parse</p>
+     * @param tagPrefix      <p>The prefix differentiating a tag from a material</p>
+     * @param logger         <p>The logger to use for logging parsing errors</p>
+     * @return <p>The materials defined by the material string, or an empty list if none were found</p>
+     */
+    public static @NotNull Set<Material> loadMaterialString(@NotNull String materialString, @NotNull String tagPrefix,
+                                                            @NotNull Logger logger) {
+        Set<Material> parsedMaterials = new HashSet<>();
+        // Try to parse a material tag first
+        if (parseMaterialTag(parsedMaterials, materialString, tagPrefix, logger)) {
+            return parsedMaterials;
+        }
+
+        // Try to parse a material name
+        Material matched = loadMaterialString(materialString, logger);
+        if (matched != null) {
+            parsedMaterials.add(matched);
+        }
+
+        return parsedMaterials;
+    }
+
+    /**
+     * Parses a string representing a material
+     *
+     * @param materialString <p>The material string to parse</p>
+     * @param logger         <p>The logger to use for logging parsing errors</p>
+     * @return <p>The material defined by the material string, or null if not found</p>
+     */
+    public static @Nullable Material loadMaterialString(@NotNull String materialString, @NotNull Logger logger) {
+        // Try to parse a material name
+        Material matched = Material.matchMaterial(materialString.replace("-", "_"));
+        if (matched != null) {
+            return matched;
+        } else {
+            logger.log(Level.WARNING, StringFormatter.replacePlaceholder("Unable to parse material: {material}",
+                    "{material}", materialString));
+            return null;
+        }
+    }
+
+    /**
+     * Tries to parse the material tag in the specified material name
+     *
+     * @param targetSet    <p>The set all parsed materials should be added to</p>
+     * @param materialName <p>The material name that might be a material tag</p>
+     * @param tagPrefix    <p>The prefix differentiating a tag from a material</p>
+     * @param logger       <p>The logger to use for logging parsing errors</p>
+     * @return <p>True if a tag was found</p>
+     */
+    private static boolean parseMaterialTag(@NotNull Set<Material> targetSet, @NotNull String materialName,
+                                            @NotNull String tagPrefix, @NotNull Logger logger) {
+        Pattern pattern = Pattern.compile("^" + Pattern.quote(tagPrefix) + "([a-zA-Z_]+)");
+        Matcher matcher = pattern.matcher(materialName);
+        if (matcher.find()) {
+            // The material is a material tag
+            Tag<Material> tag = Bukkit.getTag(Tag.REGISTRY_BLOCKS, NamespacedKey.minecraft(
+                    matcher.group(1).toLowerCase()), Material.class);
+            if (tag != null) {
+                targetSet.addAll(tag.getValues());
+            } else {
+                logger.log(Level.WARNING, StringFormatter.replacePlaceholder(
+                        "Unable to parse material: {material}", "{material}", materialName));
+            }
+            return true;
+        }
+        return false;
+    }
+
+}

src/main/java/net/knarcraft/knarlib/util/ParticleHelper.java

@@ -0,0 +1,242 @@
+package net.knarcraft.knarlib.util;
+
+import net.knarcraft.knarlib.particle.ParticleConfig;
+import org.bukkit.Location;
+import org.bukkit.World;
+import org.bukkit.block.Block;
+import org.bukkit.util.BoundingBox;
+import org.bukkit.util.Vector;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.UUID;
+
+/**
+ * A helper class for spawning particle effects
+ */
+@SuppressWarnings("unused")
+public final class ParticleHelper {
+
+    private static final Map<UUID, Vector[]> pyramidVectors = new HashMap<>();
+    private static final Map<UUID, Double[][]> circleCoordinates = new HashMap<>();
+    private static final Map<UUID, Double[][]> sphereCoordinates = new HashMap<>();
+
+    private ParticleHelper() {
+
+    }
+
+    /**
+     * Removes any stored calculations for the given id
+     *
+     * <p>If you frequently change the id without clearing, you'll create a memory leak!</p>
+     *
+     * @param id <p>The id specified when generating a shape</p>
+     */
+    public static void clearStoredCalculations(UUID id) {
+        pyramidVectors.remove(id);
+        circleCoordinates.remove(id);
+        sphereCoordinates.remove(id);
+    }
+
+    /**
+     * Spawns a cube of particles at the given location
+     *
+     * <p>It is recommended to only spawn one particle with no spread, and a density between 1 and 0.01</p>
+     *
+     * @param world          <p>The world to spawn the particles in</p>
+     * @param location       <p>The location of the block to spawn the particles at</p>
+     * @param particleConfig <p>The configuration describing the particle to spawn</p>
+     * @param blockHeight    <p>The height of the block to spawn the particle above</p>
+     */
+    public static void drawCube(@NotNull World world, @NotNull Location location, @NotNull ParticleConfig particleConfig,
+                                double blockHeight) {
+        // Draw the top and bottom of the cube
+        drawSquare(world, location, particleConfig, blockHeight);
+        drawSquare(world, location.clone().add(0, 1, 0), particleConfig, blockHeight);
+
+        for (double y = 0; y <= 1; y += particleConfig.getParticleDensity()) {
+            double height = particleConfig.getHeightOffset() + y;
+            spawnParticle(world, location.clone().add(0, height, 0), particleConfig, blockHeight);
+            spawnParticle(world, location.clone().add(0, height, 1), particleConfig, blockHeight);
+            spawnParticle(world, location.clone().add(1, height, 0), particleConfig, blockHeight);
+            spawnParticle(world, location.clone().add(1, height, 1), particleConfig, blockHeight);
+        }
+    }
+
+    /**
+     * Spawns a sphere of particles at the given location
+     *
+     * <p>It is recommended to only spawn one particle with no spread, and a density between 4 and 0.1</p>
+     *
+     * @param world                <p>The world to spawn the particles in</p>
+     * @param location             <p>The location of the block to spawn the particles at</p>
+     * @param particleConfig       <p>The configuration describing the particle to spawn</p>
+     * @param blockHeight          <p>The height of the block to spawn the particle above</p>
+     * @param storedCalculationsId <p>An id for stored calculations. Use clearStoredCalculations with this id later.</p>
+     */
+    public static void drawSphere(@NotNull World world, @NotNull Location location, @NotNull ParticleConfig particleConfig,
+                                  double blockHeight, UUID storedCalculationsId) {
+        // For spheres, densities below 0.1 has weird bugs such as blinking in and out of existence, and floating point
+        // errors when calculating the length of circleCoordinates
+        double density = Math.max(1, particleConfig.getParticleDensity());
+        // Store calculations for improved efficiency
+        if (sphereCoordinates.get(storedCalculationsId) == null) {
+            int length = (int) Math.ceil((180 / density));
+            Double[][] coordinates = new Double[length * 3][];
+            double height = particleConfig.getHeightOffset() + 0.5;
+            int i = 0;
+            for (double x = 0; x < 180; x += density) {
+                if (i >= coordinates.length) {
+                    continue;
+                }
+
+                double cos = 0.5 * Math.cos(x);
+                double sin = 0.5 * Math.sin(x);
+                coordinates[i++] = new Double[]{sin + 0.5, height, cos + 0.5};
+                coordinates[i++] = new Double[]{sin + 0.5, height + cos, 0.5};
+                coordinates[i++] = new Double[]{0.5, height + sin, cos + 0.5};
+            }
+            sphereCoordinates.put(storedCalculationsId, coordinates);
+        }
+
+        // Spawn particles on the stored locations, relative to the launchpad
+        for (Double[] sphereCoordinate : sphereCoordinates.get(storedCalculationsId)) {
+            spawnParticle(world, location.clone().add(sphereCoordinate[0], sphereCoordinate[1], sphereCoordinate[2]),
+                    particleConfig, blockHeight);
+        }
+    }
+
+    /**
+     * Spawns a pyramid of particles at the given location
+     *
+     * <p>It is recommended to only spawn one particle with no spread, and a density between 1 and 0.01</p>
+     *
+     * @param world                <p>The world to spawn the particles in</p>
+     * @param location             <p>The location of the block to spawn the particles at</p>
+     * @param particleConfig       <p>The configuration describing the particle to spawn</p>
+     * @param blockHeight          <p>The height of the block to spawn the particle above</p>
+     * @param storedCalculationsId <p>An id for stored calculations. Use clearStoredCalculations with this id later.</p>
+     */
+    public static void drawPyramid(@NotNull World world, @NotNull Location location, @NotNull ParticleConfig particleConfig,
+                                   double blockHeight, UUID storedCalculationsId) {
+        // Draw the bottom of the pyramid
+        drawSquare(world, location, particleConfig, blockHeight);
+
+        // Store calculations for improved efficiency
+        if (pyramidVectors.get(storedCalculationsId) == null) {
+            // The 0.5 offsets are required for the angle of the pyramid's 4 lines to be correct
+            double height = particleConfig.getHeightOffset();
+            double coordinateMin = -0.5 * height;
+            double coordinateMax = 1 + (0.5 * height);
+
+            Vector[] vectors = new Vector[5];
+            // The vector from the origin to the top of the pyramid
+            vectors[0] = new Vector(0.5, 1 + height, 0.5);
+            // The vectors from the top of the pyramid towards each corner
+            vectors[1] = new Vector(coordinateMin, 0, coordinateMin).subtract(vectors[0]).normalize();
+            vectors[2] = new Vector(coordinateMax, 0, coordinateMin).subtract(vectors[0]).normalize();
+            vectors[3] = new Vector(coordinateMin, 0, coordinateMax).subtract(vectors[0]).normalize();
+            vectors[4] = new Vector(coordinateMax, 0, coordinateMax).subtract(vectors[0]).normalize();
+            pyramidVectors.put(storedCalculationsId, vectors);
+        }
+
+        Vector[] storedVectors = pyramidVectors.get(storedCalculationsId);
+        Location topLocation = location.clone().add(storedVectors[0]);
+        for (double x = 0; x <= 1.2; x += particleConfig.getParticleDensity()) {
+            spawnParticle(world, topLocation.clone().add(storedVectors[1].clone().multiply(x)), particleConfig, blockHeight);
+            spawnParticle(world, topLocation.clone().add(storedVectors[2].clone().multiply(x)), particleConfig, blockHeight);
+            spawnParticle(world, topLocation.clone().add(storedVectors[3].clone().multiply(x)), particleConfig, blockHeight);
+            spawnParticle(world, topLocation.clone().add(storedVectors[4].clone().multiply(x)), particleConfig, blockHeight);
+        }
+    }
+
+    /**
+     * Spawns a circle of particles at the given location
+     *
+     * <p>It is recommended to only spawn one particle with no spread, and a density between 4 and 0.1</p>
+     *
+     * @param world                <p>The world to spawn the particles in</p>
+     * @param location             <p>The location of the block to spawn the particles at</p>
+     * @param particleConfig       <p>The configuration describing the particle to spawn</p>
+     * @param blockHeight          <p>The height of the block to spawn the particle above</p>
+     * @param storedCalculationsId <p>An id for stored calculations. Use clearStoredCalculations with this id later.</p>
+     */
+    public static void drawCircle(@NotNull World world, @NotNull Location location, @NotNull ParticleConfig particleConfig,
+                                  double blockHeight, UUID storedCalculationsId) {
+        // For circles, densities below 0.1 has weird bugs such as blinking in and out of existence, and floating point
+        // errors when calculating the length of circleCoordinates
+        double density = Math.max(1, particleConfig.getParticleDensity());
+        // Store calculations for improved efficiency
+        if (circleCoordinates.get(storedCalculationsId) == null) {
+            Double[][] coordinates = new Double[(int) Math.ceil((180 / density))][];
+            int i = 0;
+            for (double x = 0; x < 180; x += density) {
+                if (i >= coordinates.length) {
+                    continue;
+                }
+                coordinates[i++] = new Double[]{(0.5 * Math.sin(x)) + 0.5, (0.5 * Math.cos(x)) + 0.5};
+            }
+            circleCoordinates.put(storedCalculationsId, coordinates);
+        }
+
+        // Spawn particles on the stored locations, relative to the launchpad
+        for (Double[] circleCoordinate : circleCoordinates.get(storedCalculationsId)) {
+            spawnParticle(world, location.clone().add(circleCoordinate[0], particleConfig.getHeightOffset(),
+                    circleCoordinate[1]), particleConfig, blockHeight);
+        }
+    }
+
+    /**
+     * Spawns a square of particles at the given location
+     *
+     * <p>It is recommended to only spawn one particle with no spread, and a density between 1 and 0.01</p>
+     *
+     * @param world          <p>The world to spawn the particles in</p>
+     * @param location       <p>The location of the block to spawn the particles at</p>
+     * @param particleConfig <p>The configuration describing the particle to spawn</p>
+     * @param blockHeight    <p>The height of the block to spawn the particle above</p>
+     */
+    public static void drawSquare(@NotNull World world, @NotNull Location location, @NotNull ParticleConfig particleConfig,
+                                  double blockHeight) {
+        for (double x = 0; x <= 1; x += particleConfig.getParticleDensity()) {
+            spawnParticle(world, location.clone().add(x, particleConfig.getHeightOffset(), 0), particleConfig, blockHeight);
+            spawnParticle(world, location.clone().add(x, particleConfig.getHeightOffset(), 1), particleConfig, blockHeight);
+            spawnParticle(world, location.clone().add(0, particleConfig.getHeightOffset(), x), particleConfig, blockHeight);
+            spawnParticle(world, location.clone().add(1, particleConfig.getHeightOffset(), x), particleConfig, blockHeight);
+        }
+    }
+
+    /**
+     * Spawns the specified particle at the given location
+     *
+     * @param world          <p>The world to spawn the particle in</p>
+     * @param location       <p>The location to spawn the particle at</p>
+     * @param particleConfig <p>The configuration describing the particle to spawn</p>
+     * @param blockHeight    <p>The height of the block to spawn the particle above</p>
+     */
+    public static void spawnParticle(@NotNull World world, @NotNull Location location,
+                                     @NotNull ParticleConfig particleConfig, double blockHeight) {
+        world.spawnParticle(particleConfig.getParticleType(),
+                location.add(0, blockHeight, 0), particleConfig.getParticleAmount(),
+                particleConfig.getOffsetX(), particleConfig.getOffsetY(), particleConfig.getOffsetZ(),
+                particleConfig.getExtra());
+    }
+
+    /**
+     * Gets the height of the block at the given location
+     *
+     * @param block <p>The block to check</p>
+     * @return <p>The height of the block</p>
+     */
+    public static double getBlockHeight(@NotNull Block block) {
+        double maxY = 0;
+        for (BoundingBox boundingBox : block.getCollisionShape().getBoundingBoxes()) {
+            if (boundingBox.getMaxY() > maxY) {
+                maxY = boundingBox.getMaxY();
+            }
+        }
+        return maxY;
+    }
+
+}

src/main/java/net/knarcraft/knarlib/util/TabCompletionHelper.java

@@ -1,7 +1,11 @@
 package net.knarcraft.knarlib.util;
 
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
 import java.util.ArrayList;
 import java.util.List;
+import java.util.function.BiFunction;
 
 /**
  * Helper class for getting string lists required for auto-completion
@@ -12,6 +16,58 @@ public final class TabCompletionHelper {
     private TabCompletionHelper() {
     }
 
+    /**
+     * Finds available tab-completions for a list where several comma-separated values are allowed
+     *
+     * <p>If, for example, the available values are [fish,potatoes,stew,strawberries], and the player has already typed
+     * "fish,potatoes,", then available tab-completions become fish,potatoes,stew and fish,potatoes,strawberries.</p>
+     *
+     * @param values    <p>The available tab-completion values</p>
+     * @param typedText <p>The text the player has typed</p>
+     * @param filterer  <p>The filterer (filterMatching) to use to filter by typed text</p>
+     * @return <p>Available tab-completions</p>
+     */
+    public static @NotNull List<String> getStringList(@NotNull List<String> values, @NotNull String typedText,
+                                                      @Nullable BiFunction<List<String>, String, List<String>> filterer) {
+        if (typedText.isBlank() || !typedText.contains(",")) {
+            if (filterer != null) {
+                return filterer.apply(values, typedText);
+            } else {
+                return values;
+            }
+        } else {
+            // The argument base is everything the player has typed, until the last comma
+            List<String> arguments = List.of(typedText.split(","));
+            String base;
+            List<String> baseArguments;
+            if (typedText.endsWith(",")) {
+                baseArguments = arguments;
+            } else {
+                baseArguments = arguments.subList(0, arguments.size() - 1);
+            }
+            base = String.join(",", baseArguments) + ",";
+            String lastArgument = arguments.get(arguments.size() - 1);
+
+            // Filter available values by the text after the last comma only
+            List<String> filtered;
+            if (filterer != null && !typedText.endsWith(",")) {
+                filtered = filterer.apply(new ArrayList<>(values), lastArgument);
+            } else {
+                filtered = values;
+            }
+
+            // Remove any already used values
+            List<String> unused = new ArrayList<>();
+            for (String string : filtered) {
+                if (!baseArguments.contains(string)) {
+                    unused.add(base + string);
+                }
+            }
+
+            return unused;
+        }
+    }
+
     /**
      * Finds tab complete values that contain the typed text
      *
@@ -19,7 +75,7 @@ public final class TabCompletionHelper {
      * @param typedText <p>The text the player has started typing</p>
      * @return <p>The given string values that contain the player's typed text</p>
      */
-    public static List<String> filterMatchingContains(List<String> values, String typedText) {
+    public static @NotNull List<String> filterMatchingContains(@NotNull List<String> values, @NotNull String typedText) {
         List<String> configValues = new ArrayList<>();
         for (String value : values) {
             if (value.toLowerCase().contains(typedText.toLowerCase())) {
@@ -36,7 +92,7 @@ public final class TabCompletionHelper {
      * @param typedText <p>The text the player has started typing</p>
      * @return <p>The given string values that start with the player's typed text</p>
      */
-    public static List<String> filterMatchingStartsWith(List<String> values, String typedText) {
+    public static @NotNull List<String> filterMatchingStartsWith(@NotNull List<String> values, @NotNull String typedText) {
         List<String> configValues = new ArrayList<>();
         for (String value : values) {
             if (value.toLowerCase().startsWith(typedText.toLowerCase())) {
@@ -46,4 +102,15 @@ public final class TabCompletionHelper {
         return configValues;
     }
 
+    /**
+     * Gets the "base" string from the given arguments, not including the incomplete last argument
+     *
+     * @param arguments <p>The string arguments to get the base of</p>
+     * @return <p>The base string</p>
+     */
+    private static @NotNull String getBase(@NotNull List<String> arguments) {
+        List<String> baseArray = arguments.subList(0, arguments.size() - 1);
+        return String.join(",", baseArray) + ",";
+    }
+
 }

src/main/java/net/knarcraft/knarlib/util/UpdateChecker.java

@@ -2,6 +2,8 @@ package net.knarcraft.knarlib.util;
 
 import org.bukkit.plugin.Plugin;
 import org.bukkit.scheduler.BukkitScheduler;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.io.BufferedReader;
 import java.io.IOException;
@@ -33,8 +35,9 @@ public final class UpdateChecker {
      * @param getVersionSupplier <p>The supplier used to get the current plugin version</p>
      * @param setVersionMethod   <p>A method to call with the new version as an argument. Can be used to alert admins about an available update or similar.</p>
      */
-    public static void checkForUpdate(Plugin plugin, String apiResourceURL, Supplier<String> getVersionSupplier,
+    public static void checkForUpdate(@NotNull Plugin plugin, @NotNull String apiResourceURL,
-                                      Consumer<String> setVersionMethod) {
+                                      @NotNull Supplier<String> getVersionSupplier,
+                                      @Nullable Consumer<String> setVersionMethod) {
         BukkitScheduler scheduler = plugin.getServer().getScheduler();
         scheduler.runTaskAsynchronously(plugin, () -> UpdateChecker.queryAPI(plugin, apiResourceURL, getVersionSupplier,
                 setVersionMethod));
@@ -48,8 +51,9 @@ public final class UpdateChecker {
      * @param getVersionMethod <p>The supplier used to get the current plugin version</p>
      * @param setVersionMethod <p>A method to call with the new version as an argument. Can be used to alert admins about an available update or similar.</p>
      */
-    private static void queryAPI(Plugin plugin, String APIResourceURL, Supplier<String> getVersionMethod,
+    private static void queryAPI(@NotNull Plugin plugin, @NotNull String APIResourceURL,
-                                 Consumer<String> setVersionMethod) {
+                                 @NotNull Supplier<String> getVersionMethod,
+                                 @Nullable Consumer<String> setVersionMethod) {
         try {
             InputStream inputStream = new URL(APIResourceURL).openStream();
             BufferedReader reader = FileHelper.getBufferedReaderFromInputStream(inputStream);
@@ -77,7 +81,7 @@ public final class UpdateChecker {
      * @param oldVersion <p>The old (current) plugin version</p>
      * @return <p>The string to display</p>
      */
-    public static String getUpdateAvailableString(String newVersion, String oldVersion) {
+    public static @NotNull String getUpdateAvailableString(@NotNull String newVersion, @NotNull String oldVersion) {
         return String.format(updateNotice, newVersion, oldVersion);
     }
 
@@ -88,7 +92,7 @@ public final class UpdateChecker {
      * @param newVersion <p>The new version to check</p>
      * @return <p>True if the new version is higher than the old one</p>
      */
-    public static boolean isVersionHigher(String oldVersion, String newVersion) {
+    public static boolean isVersionHigher(@NotNull String oldVersion, @NotNull String newVersion) {
         oldVersion = removeNonNumericCharacters(oldVersion);
         newVersion = removeNonNumericCharacters(newVersion);
         String[] oldVersionParts = oldVersion.split("\\.");
@@ -110,7 +114,7 @@ public final class UpdateChecker {
      * @param versionString <p>The version string to clean</p>
      * @return <p>The string with non-numeric characters replaced</p>
      */
-    private static String removeNonNumericCharacters(String versionString) {
+    private static @NotNull String removeNonNumericCharacters(@NotNull String versionString) {
         return versionString.replaceAll("[^0-9.]", "");
     }
 

src/test/java/net/knarcraft/knarlib/util/TabCompletionHelperTest.java

@@ -0,0 +1,82 @@
+package net.knarcraft.knarlib.util;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * Tests for the tab-completion helper
+ */
+public class TabCompletionHelperTest {
+
+    @Test
+    public void getStringListUnfilteredTest() {
+        List<String> input = List.of("a", "b", "c", "d");
+        List<String> result = TabCompletionHelper.getStringList(input, "a,b,", null);
+        List<String> expected = List.of("a,b,c", "a,b,d");
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void getStringListUnfilteredTest2() {
+        List<String> input = List.of("a", "b", "c", "d");
+        List<String> result = TabCompletionHelper.getStringList(input, "a,b", null);
+        List<String> expected = List.of("a,b", "a,c", "a,d");
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void getStringListContainsTest() {
+        List<String> input = List.of("ape", "ball", "car", "donut");
+        List<String> result = TabCompletionHelper.getStringList(input, "ball,donut,r",
+                TabCompletionHelper::filterMatchingContains);
+        List<String> expected = List.of("ball,donut,car");
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void getStringListContainsTest2() {
+        List<String> input = List.of("ape", "ball", "car", "donut");
+        List<String> result = TabCompletionHelper.getStringList(input, "ball,donut,",
+                TabCompletionHelper::filterMatchingContains);
+        List<String> expected = List.of("ball,donut,ape", "ball,donut,car");
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void getStringListStartsWithTest() {
+        List<String> input = List.of("ape", "ball", "car", "donut");
+        List<String> result = TabCompletionHelper.getStringList(input, "ball,donut,a",
+                TabCompletionHelper::filterMatchingStartsWith);
+        List<String> expected = List.of("ball,donut,ape");
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void getStringListStartsWithTest2() {
+        List<String> input = List.of("ape", "ball", "car", "donut");
+        List<String> result = TabCompletionHelper.getStringList(input, "ball,donut,",
+                TabCompletionHelper::filterMatchingStartsWith);
+        List<String> expected = List.of("ball,donut,ape", "ball,donut,car");
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void filterMatchingContainsTest() {
+        List<String> input = List.of("fish", "ape", "banana", "toy", "human", "stick", "potato", "detergent", "magazine");
+        List<String> result = TabCompletionHelper.filterMatchingContains(input, "a");
+        List<String> expected = List.of("ape", "banana", "human", "potato", "magazine");
+        assertEquals(expected, result);
+    }
+
+    @Test
+    public void filterMatchingStartsWithTest() {
+        List<String> input = List.of("fish", "ape", "banana", "toy", "human", "stick", "potato", "detergent", "magazine");
+        List<String> result = TabCompletionHelper.filterMatchingStartsWith(input, "a");
+        List<String> expected = List.of("ape");
+        assertEquals(expected, result);
+    }
+
+}