Makes some improvements

Saves the downloaded BuildTools version to the server version container
Adds a check to see whether the BuildTools file exists
Adds a helper function for reading local files

src/main/java/net/knarcraft/minecraftserverlauncher/server/Server.java

@@ -532,9 +532,9 @@ public class Server {
 
     /**
      * Returns the first regex capture group found in a pattern
-     * @param pattern <p>The regex pattern to use.</p>
-     * @param text <p>The string to execute the pattern on.</p>
-     * @return <p>The first capture group if a match is found. An empty string otherwise.</p>
+     * @param pattern <p>The regex pattern to use</p>
+     * @param text <p>The string to execute the pattern on</p>
+     * @return <p>The first capture group if a match is found. An empty string otherwise</p>
      */
     private String getFirstRegexCaptureGroup(String pattern, String text) {
         Pattern compiledPattern = Pattern.compile(pattern);

src/main/java/net/knarcraft/minecraftserverlauncher/server/ServerVersionContainer.java

@@ -21,6 +21,7 @@ public class ServerVersionContainer {
     private Map<String, String> travertineVersions;
     private Map<String, String> spongeVanillaVersions;
     private Map<String, String> spongeForgeVersions;
+    private String downloadedBuildToolsVersion;
 
     /**
      * Initializes a new server version container
@@ -56,6 +57,7 @@ public class ServerVersionContainer {
         this.travertineVersions = new HashMap<>();
         this.spongeVanillaVersions = new HashMap<>();
         this.spongeForgeVersions = new HashMap<>();
+        this.downloadedBuildToolsVersion = null;
     }
 
     @Override
@@ -66,7 +68,8 @@ public class ServerVersionContainer {
                 "waterfallVersions;" + mapToString(waterfallVersions) + "\n" +
                 "travertineVersions;" + mapToString(travertineVersions) + "\n" +
                 "spongeVanillaVersions;" + mapToString(spongeVanillaVersions) + "\n" +
-                "spongeForgeVersions;" + mapToString(spongeForgeVersions);
+                "spongeForgeVersions;" + mapToString(spongeForgeVersions) + "\n" +
+                "downloadedBuildToolsVersion;" + downloadedBuildToolsVersion;
     }
 
     /**
@@ -105,7 +108,7 @@ public class ServerVersionContainer {
                 }
             }
             file = new PrintWriter(versionFile);
-            file.println(this.toString());
+            file.println(this);
             file.close();
         } catch (IOException e) {
             e.printStackTrace();
@@ -163,6 +166,9 @@ public class ServerVersionContainer {
             case "spongeForgeVersions":
                 parseVersionsToMap(spongeForgeVersions, variableValue);
                 break;
+            case "downloadedBuildToolsVersion":
+                downloadedBuildToolsVersion = variableValue;
+                break;
             default:
                 throw new IllegalArgumentException("Invalid key encountered in the server version file.");
         }
@@ -323,5 +329,25 @@ public class ServerVersionContainer {
         spongeForgeVersions.put(mapKey, newValue);
         saveState();
     }
+
+    /**
+     * Gets the version of the downloaded BuildTools file
+     *
+     * @return <p>The version of the downloaded BuildTools file</p>
+     */
+    public String getDownloadedBuildToolsVersion() {
+        return this.downloadedBuildToolsVersion;
+    }
+
+    /**
+     * Sets the version of the downloaded BuildTools file
+     *
+     * @param newValue <p>The new version</p></p>
+     */
+    public void setDownloadedBuildToolsVersion(String newValue) {
+        this.downloadedBuildToolsVersion = newValue;
+        saveState();
+    }
+
 }
 

src/main/java/net/knarcraft/minecraftserverlauncher/server/servertypes/BungeeCord.java

@@ -7,7 +7,7 @@ import java.io.IOException;
 import java.nio.file.Paths;
 
 import static net.knarcraft.minecraftserverlauncher.utility.CommonFunctions.downloadFile;
-import static net.knarcraft.minecraftserverlauncher.utility.CommonFunctions.readFile;
+import static net.knarcraft.minecraftserverlauncher.utility.CommonFunctions.readRemoteFile;
 import static net.knarcraft.minecraftserverlauncher.utility.CommonFunctions.stringBetween;
 
 /**
@@ -65,7 +65,7 @@ public class BungeeCord extends AbstractServerType {
     private boolean downloadLatestJar(File filePath) throws IOException {
         ServerVersionContainer versionContainer = ServerVersionContainer.getInstance();
 
-        String newestVersion = stringBetween(readFile(versionURL), srcStart, srcEnd);
+        String newestVersion = stringBetween(readRemoteFile(versionURL), srcStart, srcEnd);
         String oldVersion = versionContainer.getBungeeVersion();
         //The file is already the newest version
         if (filePath.isFile() && newestVersion.equals(oldVersion)) {

src/main/java/net/knarcraft/minecraftserverlauncher/server/servertypes/SpongeVanilla.java

@@ -53,7 +53,7 @@ public class SpongeVanilla extends AbstractServerType {
         String file = this.getName() + version + ".jar";
         File filePath = new File(folder + file);
 
-        String versionText = CommonFunctions.readFile(versionURL + version);
+        String versionText = CommonFunctions.readRemoteFile(versionURL + version);
         String newestVersion = CommonFunctions.stringBetween(versionText, srcStart, srcEnd);
 
         String jarURL = downloadURL + newestVersion + downloadURLPart + newestVersion + ".jar";

src/main/java/net/knarcraft/minecraftserverlauncher/server/servertypes/Vanilla.java

@@ -12,7 +12,7 @@ import java.io.IOException;
 import java.nio.file.Paths;
 
 import static net.knarcraft.minecraftserverlauncher.utility.CommonFunctions.downloadFile;
-import static net.knarcraft.minecraftserverlauncher.utility.CommonFunctions.readFile;
+import static net.knarcraft.minecraftserverlauncher.utility.CommonFunctions.readRemoteFile;
 
 /**
  * This class represents the regular vanilla Minecraft server type
@@ -90,7 +90,7 @@ public class Vanilla extends AbstractServerType {
      * @throws IOException <p>If the remote resource cannot be readFromServer</p>
      */
     private String[] getLatestFile(String releaseType) throws IOException {
-        String versionText = readFile(versionURL);
+        String versionText = readRemoteFile(versionURL);
         JsonObject jsonObject = new JsonParser().parse(versionText).getAsJsonObject();
         String latest = jsonObject.getAsJsonObject("latest").get(releaseType).getAsString();
         String versionURL = getServerFileVersionURL(latest);
@@ -106,7 +106,7 @@ public class Vanilla extends AbstractServerType {
      * @throws IOException <p>If the remote resource cannot be readFromServer</p>
      */
     private String getVanillaDownloadURL(String versionURL) throws IOException {
-        String versionText = readFile(versionURL);
+        String versionText = readRemoteFile(versionURL);
         JsonObject jsonObject = new JsonParser().parse(versionText).getAsJsonObject();
         return jsonObject.getAsJsonObject("downloads").getAsJsonObject("server").get("url").getAsString();
     }
@@ -119,7 +119,7 @@ public class Vanilla extends AbstractServerType {
      * @throws IOException <p>If the file cannot be downloaded</p>
      */
     private String getServerFileVersionURL(String targetVersion) throws IOException {
-        String versionText = readFile(versionURL);
+        String versionText = readRemoteFile(versionURL);
         JsonObject jsonObject = new JsonParser().parse(versionText).getAsJsonObject();
         JsonArray availableVersions = jsonObject.getAsJsonArray("versions");
         for (JsonElement availableVersion : availableVersions) {

src/main/java/net/knarcraft/minecraftserverlauncher/server/servertypes/Waterfall.java

@@ -9,7 +9,7 @@ import java.util.function.BiConsumer;
 import java.util.function.Function;
 
 import static net.knarcraft.minecraftserverlauncher.utility.CommonFunctions.downloadFile;
-import static net.knarcraft.minecraftserverlauncher.utility.CommonFunctions.readFile;
+import static net.knarcraft.minecraftserverlauncher.utility.CommonFunctions.readRemoteFile;
 import static net.knarcraft.minecraftserverlauncher.utility.CommonFunctions.stringBetween;
 
 /**
@@ -50,7 +50,7 @@ public class Waterfall extends AbstractServerType {
     public boolean downloadJar(String folder, String version) throws IOException {
         String file = this.getName() + version + ".jar";
         File filePath = new File(folder + file);
-        String newestVersion = stringBetween(readFile(versionURL + version), srcStart, srcEnd);
+        String newestVersion = stringBetween(readRemoteFile(versionURL + version), srcStart, srcEnd);
         String fullURL = downloadURL + version + "/" + newestVersion + "/download";
         String oldVersion = oldVersionFunction.apply(version);
         //The file is already the newest version