Added party alliances

Adds the following commands:
`/party alliance`
`/party alliance invite <target>`
`/party alliance accept`

Allies will share party chat and will not be able to harm eachother.
Item and XP sharing is limitied to a single party. Allowing two parties
to team up without sharing resources and XP.

Closes #1009

src/main/java/com/gmail/nossr50/api/PartyAPI.java

@@ -174,4 +174,17 @@ public final class PartyAPI {
     public static List<Player> getOnlineMembers(Player player) {
         return PartyManager.getOnlineMembers(player);
     }
+
+    public static boolean hasAlly(String partyName) {
+        return PartyManager.getParty(partyName).getAlly() != null;
+    }
+
+    public static String getAllyName(String partyName) {
+        Party ally = PartyManager.getParty(partyName).getAlly();
+        if (ally != null) {
+            return ally.getName();
+        }
+
+        return null;
+    }
 }

src/main/java/com/gmail/nossr50/chat/PartyChatManager.java

@@ -10,6 +10,7 @@ import org.bukkit.plugin.Plugin;
 import com.gmail.nossr50.config.Config;
 import com.gmail.nossr50.datatypes.party.Party;
 import com.gmail.nossr50.events.chat.McMMOPartyChatEvent;
+import com.gmail.nossr50.locale.LocaleLoader;
 
 public class PartyChatManager extends ChatManager {
     private Party party;
@@ -37,6 +38,13 @@ public class PartyChatManager extends ChatManager {
             member.sendMessage(message);
         }
 
+        if (party.getAlly() != null) {
+            for (Player member : party.getAlly().getOnlineMembers()) {
+                String allyPrefix = LocaleLoader.formatString(Config.getInstance().getPartyChatPrefixAlly());
+                member.sendMessage(allyPrefix + message);
+            }
+        }
+
         plugin.getLogger().info("[P]<" + party.getName() + ">" + message);
     }
 }

src/main/java/com/gmail/nossr50/commands/party/PartyCommand.java

@@ -14,6 +14,7 @@ import org.bukkit.util.StringUtil;
 
 import com.gmail.nossr50.mcMMO;
 import com.gmail.nossr50.commands.chat.PartyChatCommand;
+import com.gmail.nossr50.commands.party.alliance.PartyAllianceCommand;
 import com.gmail.nossr50.commands.party.teleport.PtpCommand;
 import com.gmail.nossr50.datatypes.player.McMMOPlayer;
 import com.gmail.nossr50.locale.LocaleLoader;
@@ -56,6 +57,7 @@ public class PartyCommand implements TabExecutor {
     private CommandExecutor partyHelpCommand           = new PartyHelpCommand();
     private CommandExecutor partyTeleportCommand       = mcMMO.p.getCommand("ptp").getExecutor();
     private CommandExecutor partyChatCommand           = new PartyChatCommand();
+    private CommandExecutor partyAllianceCommand       = new PartyAllianceCommand();
 
     @Override
     public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
@@ -150,6 +152,8 @@ public class PartyCommand implements TabExecutor {
                 return partyChangePasswordCommand.onCommand(sender, command, label, args);
             case RENAME:
                 return partyRenameCommand.onCommand(sender, command, label, args);
+            case ALLIANCE:
+                return partyAllianceCommand.onCommand(sender, command, label, args);
             default:
                 break;
         }

src/main/java/com/gmail/nossr50/commands/party/PartyInfoCommand.java

@@ -93,6 +93,10 @@ public class PartyInfoCommand implements CommandExecutor {
     private void displayPartyHeader(Player player, Party party) {
         player.sendMessage(LocaleLoader.getString("Commands.Party.Header"));
         player.sendMessage(LocaleLoader.getString("Commands.Party.Status", party.getName(), LocaleLoader.getString("Party.Status." + (party.isLocked() ? "Locked" : "Unlocked"))));
+
+        if (party.getAlly() != null) {
+            player.sendMessage(LocaleLoader.getString("Commands.Party.Status.Alliance", party.getAlly().getName()));
+        }
     }
 
     private void displayMemberInfo(Player player, McMMOPlayer mcMMOPlayer, Party party) {

src/main/java/com/gmail/nossr50/commands/party/PartySubcommandType.java

@@ -18,7 +18,8 @@ public enum PartySubcommandType {
     PASSWORD,
     RENAME,
     TELEPORT,
-    CHAT;
+    CHAT,
+    ALLIANCE;
 
     public static PartySubcommandType getSubcommand(String commandName) {
         for (PartySubcommandType command : values()) {
@@ -42,6 +43,9 @@ public enum PartySubcommandType {
         else if (commandName.equalsIgnoreCase("shareitem") || commandName.equalsIgnoreCase("shareitems")) {
             return ITEMSHARE;
         }
+        else if (commandName.equalsIgnoreCase("ally")) {
+            return ALLIANCE;
+        }
 
         return null;
     }

src/main/java/com/gmail/nossr50/commands/party/alliance/PartyAllianceAcceptCommand.java

@@ -0,0 +1,34 @@
+package com.gmail.nossr50.commands.party.alliance;
+
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+
+import com.gmail.nossr50.datatypes.player.McMMOPlayer;
+import com.gmail.nossr50.locale.LocaleLoader;
+import com.gmail.nossr50.party.PartyManager;
+import com.gmail.nossr50.util.player.UserManager;
+
+public class PartyAllianceAcceptCommand implements CommandExecutor {
+    @Override
+    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
+        switch (args.length) {
+            case 2:
+                Player player = (Player) sender;
+                McMMOPlayer mcMMOPlayer = UserManager.getPlayer(player);
+
+                if (!mcMMOPlayer.hasPartyAllianceInvite()) {
+                    sender.sendMessage(LocaleLoader.getString("mcMMO.NoInvites"));
+                    return true;
+                }
+
+                PartyManager.acceptAllianceInvite(mcMMOPlayer);
+                return true;
+
+            default:
+                sender.sendMessage(LocaleLoader.getString("Commands.Usage.2", "party", "alliance", "accept"));
+                return true;
+        }
+    }
+}

src/main/java/com/gmail/nossr50/commands/party/alliance/PartyAllianceCommand.java

@@ -0,0 +1,156 @@
+package com.gmail.nossr50.commands.party.alliance;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+
+import org.bukkit.ChatColor;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.TabExecutor;
+import org.bukkit.entity.Player;
+import org.bukkit.util.StringUtil;
+
+import com.gmail.nossr50.mcMMO;
+import com.gmail.nossr50.config.Config;
+import com.gmail.nossr50.datatypes.party.Party;
+import com.gmail.nossr50.datatypes.player.McMMOPlayer;
+import com.gmail.nossr50.locale.LocaleLoader;
+import com.gmail.nossr50.util.commands.CommandUtils;
+import com.gmail.nossr50.util.player.UserManager;
+
+import com.google.common.collect.ImmutableList;
+
+public class PartyAllianceCommand implements TabExecutor {
+    private Player player;
+    private Party playerParty;
+    private Party targetParty;
+
+    public static final List<String> ALLIANCE_SUBCOMMANDS = ImmutableList.of("invite", "accept", "disband");
+
+    private CommandExecutor partyAllianceInviteCommand = new PartyAllianceInviteCommand();
+    private CommandExecutor partyAllianceAcceptCommand = new PartyAllianceAcceptCommand();
+    private CommandExecutor partyAllianceDisbandCommand = new PartyAllianceDisbandCommand();
+
+    @Override
+    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
+        if (CommandUtils.noConsoleUsage(sender)) {
+            return true;
+        }
+
+        player = (Player) sender;
+        McMMOPlayer mcMMOPlayer = UserManager.getPlayer(player);
+
+        playerParty = mcMMOPlayer.getParty();
+
+        switch (args.length) {
+            case 1:
+                if (playerParty.getLevel() < Config.getInstance().getPartyFeatureUnlockLevel(PartyFeature.ALLIANCE)) {
+                    sender.sendMessage(LocaleLoader.getString("Party.Feature.Disabled.3"));
+                    return true;
+                }
+
+                if (playerParty.getAlly() == null) {
+                    printUsage();
+                    return true;
+                }
+
+                targetParty = playerParty.getAlly();
+
+                displayPartyHeader();
+                displayMemberInfo();
+                return true;
+
+            case 2:
+            case 3:
+                if (playerParty.getLevel() < Config.getInstance().getPartyFeatureUnlockLevel(PartyFeature.ALLIANCE)) {
+                    sender.sendMessage(LocaleLoader.getString("Party.Feature.Disabled.3"));
+                    return true;
+                }
+
+                if (args[1].equalsIgnoreCase("invite")) {
+                    return partyAllianceInviteCommand.onCommand(sender, command, label, args);
+                }
+
+                if (args[1].equalsIgnoreCase("accept")) {
+                    return partyAllianceAcceptCommand.onCommand(sender, command, label, args);
+                }
+
+                if (args[1].equalsIgnoreCase("disband")) {
+                    return partyAllianceDisbandCommand.onCommand(sender, command, label, args);
+                }
+
+                if (playerParty.getAlly() == null) {
+                    printUsage();
+                    return true;
+                }
+
+                targetParty = playerParty.getAlly();
+
+                displayPartyHeader();
+                displayMemberInfo();
+                return true;
+
+            default:
+                return false;
+        }
+    }
+
+    private boolean printUsage() {
+        player.sendMessage(LocaleLoader.getString("Commands.Party.Alliance.Help.0"));
+        player.sendMessage(LocaleLoader.getString("Commands.Party.Alliance.Help.1"));
+        return true;
+    }
+
+    @Override
+    public List<String> onTabComplete(CommandSender commandSender, Command command, String label, String[] args) {
+        switch (args.length) {
+            case 1:
+                List<String> matches = StringUtil.copyPartialMatches(args[0], ALLIANCE_SUBCOMMANDS, new ArrayList<String>(ALLIANCE_SUBCOMMANDS.size()));
+
+                if (matches.size() == 0) {
+                    Set<String> playerNames = UserManager.getPlayerNames();
+                    return StringUtil.copyPartialMatches(args[0], playerNames, new ArrayList<String>(playerNames.size()));
+                }
+
+                return matches;
+            default:
+                return ImmutableList.of();
+        }
+    }
+
+    private void displayPartyHeader() {
+        player.sendMessage(LocaleLoader.getString("Commands.Party.Alliance.Header"));
+        player.sendMessage(LocaleLoader.getString("Commands.Party.Alliance.Ally", playerParty.getName(), targetParty.getName()));
+    }
+
+    private void displayMemberInfo() {
+        player.sendMessage(LocaleLoader.getString("Commands.Party.Alliance.Members.Header"));
+        player.sendMessage(createMembersList(playerParty));
+        player.sendMessage(ChatColor.DARK_GRAY + "----------------------------");
+        player.sendMessage(createMembersList(targetParty));
+    }
+
+    private String createMembersList(Party party) {
+        StringBuilder memberList = new StringBuilder();
+
+        for (String memberName : party.getMembers()) {
+            Player member = mcMMO.p.getServer().getPlayerExact(memberName);
+
+            if (party.getLeader().equalsIgnoreCase(memberName)) {
+                memberList.append(ChatColor.GOLD);
+            }
+            else if (member != null) {
+                memberList.append(ChatColor.WHITE);
+            }
+            else {
+                memberList.append(ChatColor.GRAY);
+            }
+
+            memberList.append(memberName).append(" ");
+        }
+
+        return memberList.toString();
+    }
+}

src/main/java/com/gmail/nossr50/commands/party/alliance/PartyAllianceDisbandCommand.java

@@ -0,0 +1,36 @@
+package com.gmail.nossr50.commands.party.alliance;
+
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+
+import com.gmail.nossr50.datatypes.party.Party;
+import com.gmail.nossr50.datatypes.player.McMMOPlayer;
+import com.gmail.nossr50.locale.LocaleLoader;
+import com.gmail.nossr50.party.PartyManager;
+import com.gmail.nossr50.util.player.UserManager;
+
+public class PartyAllianceDisbandCommand implements CommandExecutor {
+    @Override
+    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
+        switch (args.length) {
+            case 2:
+                Player player = (Player) sender;
+                McMMOPlayer mcMMOPlayer = UserManager.getPlayer(player);
+                Party party = mcMMOPlayer.getParty();
+
+                if (party.getAlly() == null) {
+                    sender.sendMessage(LocaleLoader.getString("Commands.Party.Alliance.None"));
+                    return true;
+                }
+
+                PartyManager.disbandAlliance(player, party, party.getAlly());
+                return true;
+
+            default:
+                sender.sendMessage(LocaleLoader.getString("Commands.Usage.2", "party", "alliance", "disband"));
+                return true;
+        }
+    }
+}

src/main/java/com/gmail/nossr50/commands/party/alliance/PartyAllianceInviteCommand.java

@@ -0,0 +1,72 @@
+package com.gmail.nossr50.commands.party.alliance;
+
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+
+import com.gmail.nossr50.datatypes.party.Party;
+import com.gmail.nossr50.datatypes.player.McMMOPlayer;
+import com.gmail.nossr50.locale.LocaleLoader;
+import com.gmail.nossr50.party.PartyManager;
+import com.gmail.nossr50.util.Misc;
+import com.gmail.nossr50.util.commands.CommandUtils;
+import com.gmail.nossr50.util.player.UserManager;
+
+public class PartyAllianceInviteCommand implements CommandExecutor {
+    @Override
+    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
+        switch (args.length) {
+            case 3:
+                String targetName = CommandUtils.getMatchedPlayerName(args[2]);
+                McMMOPlayer mcMMOTarget = UserManager.getPlayer(targetName, true);
+
+                if (!CommandUtils.checkPlayerExistence(sender, targetName, mcMMOTarget)) {
+                    return false;
+                }
+
+                Player target = mcMMOTarget.getPlayer();
+                Player player = (Player) sender;
+                McMMOPlayer mcMMOPlayer = UserManager.getPlayer(player);
+                String playerName = player.getName();
+
+                if (player.equals(target)) {
+                    sender.sendMessage(LocaleLoader.getString("Party.Invite.Self"));
+                    return true;
+                }
+
+                if (!mcMMOTarget.inParty()) {
+                    player.sendMessage(LocaleLoader.getString("Party.PlayerNotInParty", targetName));
+                    return true;
+                }
+
+                if (PartyManager.inSameParty(player, target)) {
+                    sender.sendMessage(LocaleLoader.getString("Party.Player.InSameParty", targetName));
+                    return true;
+                }
+
+                if (!mcMMOTarget.getParty().getLeader().equalsIgnoreCase(targetName)) {
+                    player.sendMessage(LocaleLoader.getString("Party.Target.NotOwner", targetName));
+                    return true;
+                }
+
+                Party playerParty = mcMMOPlayer.getParty();
+
+                if (playerParty.getAlly() != null) {
+                    player.sendMessage(LocaleLoader.getString("Commands.Party.Alliance.AlreadyAllies"));
+                    return true;
+                }
+
+                mcMMOTarget.setPartyAllianceInvite(playerParty);
+
+                sender.sendMessage(LocaleLoader.getString("Commands.Invite.Success"));
+                target.sendMessage(LocaleLoader.getString("Commands.Party.Alliance.Invite.0", playerParty.getName(), playerName));
+                target.sendMessage(LocaleLoader.getString("Commands.Party.Alliance.Invite.1"));
+                return true;
+
+            default:
+                sender.sendMessage(LocaleLoader.getString("Commands.Usage.3", "party", "alliance", "invite", "<" + LocaleLoader.getString("Commands.Usage.Player") + ">"));
+                return true;
+        }
+    }
+}

src/main/java/com/gmail/nossr50/config/Config.java

@@ -212,6 +212,7 @@ public class Config extends AutoUpdateConfigLoader {
     public String getPartyChatPrefix() { return config.getString("Commands.partychat.Chat_Prefix_Format", "[[GREEN]]([[WHITE]]{0}[[GREEN]])"); }
     public boolean getPartyChatColorLeaderName() { return config.getBoolean("Commands.partychat.Gold_Leader_Name", true); }
     public boolean getPartyDisplayNames() { return config.getBoolean("Commands.partychat.Use_Display_Names", true); }
+    public String getPartyChatPrefixAlly() { return config.getString("Commands.partychat.Chat_Prefix_Format_Ally", "[[GREEN]](A)[[RESET]]"); }
 
     public String getAdminChatPrefix() { return config.getString("Commands.adminchat.Chat_Prefix_Format", "[[AQUA]][[[WHITE]]{0}[[AQUA]]]"); }
     public boolean getAdminDisplayNames() { return config.getBoolean("Commands.adminchat.Use_Display_Names", true); }

src/main/java/com/gmail/nossr50/datatypes/party/Party.java

@@ -15,6 +15,7 @@ public class Party {
     private String name;
     private String password;
     private boolean locked;
+    private Party ally;
 
     private ShareMode xpShareMode   = ShareMode.NONE;
     private ShareMode itemShareMode = ShareMode.NONE;
@@ -83,6 +84,10 @@ public class Party {
         return locked;
     }
 
+    public Party getAlly() {
+        return ally;
+    }
+
     public List<String> getItemShareCategories() {
         List<String> shareCategories = new ArrayList<String>();
 
@@ -111,6 +116,10 @@ public class Party {
         this.locked = locked;
     }
 
+    public void setAlly(Party ally) {
+        this.ally = ally;
+    }
+
     public void setXpShareMode(ShareMode xpShareMode) {
         this.xpShareMode = xpShareMode;
     }

src/main/java/com/gmail/nossr50/datatypes/player/McMMOPlayer.java

@@ -64,6 +64,7 @@ public class McMMOPlayer {
 
     private Party   party;
     private Party   invite;
+    private Party   allianceInvite;
     private int     itemShareModifier;
 
     private PartyTeleportRecord ptpRecord;
@@ -634,6 +635,22 @@ public class McMMOPlayer {
         return ptpRecord;
     }
 
+    public void setPartyAllianceInvite(Party allianceInvite) {
+        this.allianceInvite = allianceInvite;
+    }
+
+    public Party getPartyAllianceInvite() {
+        return allianceInvite;
+    }
+
+    public boolean hasPartyAllianceInvite() {
+        return (allianceInvite != null);
+    }
+
+    public void removePartyAllianceInvite() {
+        allianceInvite = null;
+    }
+
     public int getItemShareModifier() {
         if (itemShareModifier < 10) {
             setItemShareModifier(10);

src/main/java/com/gmail/nossr50/events/party/McMMOPartyAllianceChangeEvent.java

@@ -0,0 +1,90 @@
+package com.gmail.nossr50.events.party;
+
+import org.bukkit.entity.Player;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.player.PlayerEvent;
+
+public class McMMOPartyAllianceChangeEvent extends PlayerEvent implements Cancellable {
+    private String oldAlly;
+    private String newAlly;
+    private EventReason reason;
+    private boolean cancelled;
+
+    public McMMOPartyAllianceChangeEvent(Player player, String oldAlly, String newAlly, EventReason reason) {
+        super(player);
+
+        if (newAlly != null) {
+            newAlly = newAlly.replace(":", ".");
+        }
+
+        this.oldAlly = oldAlly;
+        this.newAlly = newAlly;
+        this.reason = reason;
+        this.cancelled = false;
+    }
+
+    /**
+     * @return The party being left, or null if the player was not in a party
+     */
+    public String getOldAlly() {
+        return oldAlly;
+    }
+
+    /**
+     * @return The party being joined, or null if the player is not joining a new party
+     */
+    public String getNewAlly() {
+        return newAlly;
+    }
+
+    /**
+     * @return The reason for the event being fired
+     */
+    public EventReason getReason() {
+        return reason;
+    }
+
+    /**
+     * A list of reasons why the event may have been fired
+     */
+    public enum EventReason {
+        /**
+         * Formed an alliance for the first time.
+         */
+        FORMED_ALLIANCE,
+
+        /**
+         * Left a party and did not join a new one.
+         */
+        DISBAND_ALLIANCE,
+
+        /**
+         * Any reason that doesn't fit elsewhere.
+         */
+        CUSTOM;
+    }
+
+    /** Following are required for Cancellable **/
+    @Override
+    public boolean isCancelled() {
+        return cancelled;
+    }
+
+    @Override
+    public void setCancelled(boolean cancelled) {
+        this.cancelled = cancelled;
+    }
+
+    /** Rest of file is required boilerplate for custom events **/
+    private static final HandlerList handlers = new HandlerList();
+
+    @Override
+    public HandlerList getHandlers() {
+        return handlers;
+    }
+
+    public static HandlerList getHandlerList() {
+        return handlers;
+    }
+}

src/main/java/com/gmail/nossr50/listeners/EntityListener.java

@@ -179,7 +179,7 @@ public class EntityListener implements Listener {
                 return;
             }
 
-            if (PartyManager.inSameParty(defendingPlayer, attackingPlayer) && !(Permissions.friendlyFire(attackingPlayer) && Permissions.friendlyFire(defendingPlayer))) {
+            if ((PartyManager.inSameParty(defendingPlayer, attackingPlayer) || PartyManager.areAllies(defendingPlayer, attackingPlayer)) && !(Permissions.friendlyFire(attackingPlayer) && Permissions.friendlyFire(defendingPlayer))) {
                 event.setCancelled(true);
                 return;
             }

src/main/java/com/gmail/nossr50/party/PartyManager.java

@@ -16,6 +16,7 @@ import com.gmail.nossr50.datatypes.party.ItemShareType;
 import com.gmail.nossr50.datatypes.party.Party;
 import com.gmail.nossr50.datatypes.party.ShareMode;
 import com.gmail.nossr50.datatypes.player.McMMOPlayer;
+import com.gmail.nossr50.events.party.McMMOPartyAllianceChangeEvent;
 import com.gmail.nossr50.events.party.McMMOPartyChangeEvent;
 import com.gmail.nossr50.events.party.McMMOPartyChangeEvent.EventReason;
 import com.gmail.nossr50.locale.LocaleLoader;
@@ -89,6 +90,17 @@ public final class PartyManager {
         return firstParty.equals(secondParty);
     }
 
+    public static boolean areAllies(Player firstPlayer, Player secondPlayer) {
+        Party firstParty = UserManager.getPlayer(firstPlayer).getParty();
+        Party secondParty = UserManager.getPlayer(secondPlayer).getParty();
+
+        if (firstParty == null || secondParty == null || firstParty.getAlly() == null || secondParty.getAlly() == null) {
+            return false;
+        }
+
+        return firstParty.equals(secondParty.getAlly()) && secondParty.equals(firstParty.getAlly());
+    }
+
     /**
      * Get the near party members.
      *
@@ -318,11 +330,71 @@ public final class PartyManager {
             return;
         }
 
-        mcMMOPlayer.getPlayer().sendMessage(LocaleLoader.getString("Commands.Invite.Accepted", invite.getName()));
+        mcMMOPlayer.getPlayer().sendMessage(LocaleLoader.getString("Commands.Party.Invite.Accepted", invite.getName()));
         mcMMOPlayer.removePartyInvite();
         addToParty(mcMMOPlayer, invite);
     }
 
+    /**
+     * Accept a party alliance invitation
+     *
+     * @param mcMMOPlayer The player who accepts the alliance invite
+     */
+    public static void acceptAllianceInvite(McMMOPlayer mcMMOPlayer) {
+        Party invite = mcMMOPlayer.getPartyAllianceInvite();
+        Player player = mcMMOPlayer.getPlayer();
+
+        // Check if the party still exists, it might have been disbanded
+        if (!parties.contains(invite)) {
+            player.sendMessage(LocaleLoader.getString("Party.Disband"));
+            return;
+        }
+
+        if (!handlePartyChangeAllianceEvent(player, mcMMOPlayer.getParty().getName(), invite.getName(), McMMOPartyAllianceChangeEvent.EventReason.FORMED_ALLIANCE)) {
+            return;
+        }
+
+        player.sendMessage(LocaleLoader.getString("Commands.Party.Alliance.Invite.Accepted", invite.getName()));
+        mcMMOPlayer.removePartyAllianceInvite();
+
+        createAlliance(mcMMOPlayer.getParty(), invite);
+    }
+
+    public static void createAlliance(Party firstParty, Party secondParty) {
+        firstParty.setAlly(secondParty);
+        secondParty.setAlly(firstParty);
+
+        for (Player member : firstParty.getOnlineMembers()) {
+            member.sendMessage(LocaleLoader.getString("Party.Alliance.Formed", secondParty.getName()));
+        }
+
+        for (Player member : secondParty.getOnlineMembers()) {
+            member.sendMessage(LocaleLoader.getString("Party.Alliance.Formed", firstParty.getName()));
+        }
+    }
+
+    public static boolean disbandAlliance(Player player, Party firstParty, Party secondParty){
+        if (!handlePartyChangeAllianceEvent(player, firstParty.getName(), secondParty.getName(), McMMOPartyAllianceChangeEvent.EventReason.DISBAND_ALLIANCE)) {
+            return false;
+        }
+
+        PartyManager.disbandAlliance(firstParty, secondParty);
+        return true;
+    }
+
+    private static void disbandAlliance(Party firstParty, Party secondParty) {
+        firstParty.setAlly(null);
+        secondParty.setAlly(null);
+
+        for (Player member : firstParty.getOnlineMembers()) {
+            member.sendMessage(LocaleLoader.getString("Party.Alliance.Disband", secondParty.getName()));
+        }
+
+        for (Player member : secondParty.getOnlineMembers()) {
+            member.sendMessage(LocaleLoader.getString("Party.Alliance.Disband", firstParty.getName()));
+        }
+    }
+
     /**
      * Add a player to a party
      *
@@ -406,12 +478,19 @@ public final class PartyManager {
 
         YamlConfiguration partiesFile = YamlConfiguration.loadConfiguration(partyFile);
 
+        ArrayList<Party> hasAlly = new ArrayList<Party>();
+
         for (String partyName : partiesFile.getConfigurationSection("").getKeys(false)) {
             Party party = new Party(partyName);
 
             party.setLeader(partiesFile.getString(partyName + ".Leader"));
             party.setPassword(partiesFile.getString(partyName + ".Password"));
             party.setLocked(partiesFile.getBoolean(partyName + ".Locked"));
+
+            if (partiesFile.getString(partyName + ".Ally") != null) {
+                hasAlly.add(party);
+            }
+
             party.setXpShareMode(ShareMode.getShareMode(partiesFile.getString(partyName + ".ExpShareMode", "NONE")));
             party.setItemShareMode(ShareMode.getShareMode(partiesFile.getString(partyName + ".ItemShareMode", "NONE")));
 
@@ -428,6 +507,10 @@ public final class PartyManager {
 
             parties.add(party);
         }
+
+        for (Party party : hasAlly) {
+            party.setAlly(getParty(partiesFile.getString(party.getName() + ".Ally")));
+        }
     }
 
     /**
@@ -446,6 +529,7 @@ public final class PartyManager {
             partiesFile.set(partyName + ".Leader", party.getLeader());
             partiesFile.set(partyName + ".Password", party.getPassword());
             partiesFile.set(partyName + ".Locked", party.isLocked());
+            partiesFile.set(partyName + ".Ally", (party.getAlly() != null) ? party.getAlly().getName() : "");
             partiesFile.set(partyName + ".ExpShareMode", party.getXpShareMode().toString());
             partiesFile.set(partyName + ".ItemShareMode", party.getItemShareMode().toString());
 
@@ -488,6 +572,22 @@ public final class PartyManager {
         return !event.isCancelled();
     }
 
+    /**
+     * Handle party alliance change event.
+     *
+     * @param player The player changing party alliances
+     * @param oldAllyName The name of the old ally
+     * @param newAllyName The name of the new ally
+     * @param reason The reason for changing allies
+     * @return true if the change event was successful, false otherwise
+     */
+    public static boolean handlePartyChangeAllianceEvent(Player player, String oldAllyName, String newAllyName, McMMOPartyAllianceChangeEvent.EventReason reason) {
+        McMMOPartyAllianceChangeEvent event = new McMMOPartyAllianceChangeEvent(player, oldAllyName, newAllyName, reason);
+        mcMMO.p.getServer().getPluginManager().callEvent(event);
+
+        return !event.isCancelled();
+    }
+
     /**
      * Remove party data from the mcMMOPlayer.
      *