Cleanly resume the installation, if the player quits the game and reconnects

If the installation is already running in background after the wizard, it will not stop, if the player quits the game.

EssentialsUpdate/src/com/earth2me/essentials/update/UpdateProcess.java

@@ -1,10 +1,13 @@
 package com.earth2me.essentials.update;
 
+import com.earth2me.essentials.update.states.InstallationFinishedEvent;
 import com.earth2me.essentials.update.states.StateMachine;
 import java.util.List;
 import org.bukkit.Bukkit;
 import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
+import org.bukkit.event.CustomEventListener;
+import org.bukkit.event.Event;
 import org.bukkit.event.Event.Priority;
 import org.bukkit.event.Event.Type;
 import org.bukkit.event.player.PlayerChatEvent;
@@ -32,6 +35,18 @@ public class UpdateProcess extends PlayerListener
 		final PluginManager pluginManager = plugin.getServer().getPluginManager();
 		pluginManager.registerEvent(Type.PLAYER_QUIT, this, Priority.Low, plugin);
 		pluginManager.registerEvent(Type.PLAYER_CHAT, this, Priority.Lowest, plugin);
+		pluginManager.registerEvent(Type.PLAYER_JOIN, this, Priority.Normal, plugin);
+		pluginManager.registerEvent(Type.CUSTOM_EVENT, new CustomEventListener(){
+
+			@Override
+			public void onCustomEvent(final Event event)
+			{
+				if(event instanceof InstallationFinishedEvent) {
+					UpdateProcess.this.currentPlayer = null;
+				}
+			}
+			
+		}, Priority.Normal, plugin);
 	}
 
 	@Override
@@ -58,6 +73,13 @@ public class UpdateProcess extends PlayerListener
 	public void onPlayerJoin(final PlayerJoinEvent event)
 	{
 		final Player player = event.getPlayer();
+		if (currentPlayer.getName().equals(player.getName())) {
+			currentPlayer = player;
+			player.sendMessage("You quit the game, while the installion wizard was running.");
+			player.sendMessage("The installation wizard will now resume.");
+			player.sendMessage("You can exit the wizard by typing quit into the chat.");
+			stateMachine.resumeInstallation(player);
+		}
 		if (player.hasPermission("essentials.update") && !updateCheck.isEssentialsInstalled())
 		{
 			player.sendMessage("Hello " + player.getDisplayName());

EssentialsUpdate/src/com/earth2me/essentials/update/states/InstallationFinishedEvent.java

@@ -0,0 +1,12 @@
+package com.earth2me.essentials.update.states;
+
+import org.bukkit.event.Event;
+
+
+public class InstallationFinishedEvent extends Event
+{
+	public InstallationFinishedEvent()
+	{
+		super(Type.CUSTOM_EVENT);
+	}	
+}

EssentialsUpdate/src/com/earth2me/essentials/update/states/StateMachine.java

@@ -12,11 +12,12 @@ public class StateMachine extends WorkListener
 {
 	public enum MachineResult
 	{
-		ABORT, WAIT, DONE
+		ABORT, WAIT, DONE, NONE
 	}
 	private final transient StateMap states = new StateMap();
 	private transient AbstractState current;
-	private final transient Player player;
+	private transient Player player;
+	private transient MachineResult result = MachineResult.NONE;
 
 	public StateMachine(final Plugin plugin, final Player player, final VersionInfo newVersionInfo)
 	{
@@ -37,29 +38,43 @@ public class StateMachine extends WorkListener
 			current = current.getNextState();
 			if (current == null)
 			{
-				return MachineResult.DONE;
+				result = MachineResult.DONE;
+				break;
 			}
 		}
-		current.askQuestion(player);
-		return MachineResult.WAIT;
+		if (current != null)
+		{
+			if (player.isOnline())
+			{
+				current.askQuestion(player);
+			}
+			result = MachineResult.WAIT;
+		}
+		return result;
 	}
 
 	public MachineResult reactOnMessage(final String message)
 	{
+		result = MachineResult.NONE;
 		final AbstractState next = current.reactOnAnswer(player, message);
 		if (next == null)
 		{
 			if (current.isAbortion())
 			{
-				return MachineResult.ABORT;
+				finish();
+				result = MachineResult.ABORT;
 			}
 			else
 			{
-				return MachineResult.DONE;
+				result = MachineResult.DONE;
 			}
 		}
-		current = next;
-		return askQuestion();
+		else
+		{
+			current = next;
+			askQuestion();
+		}
+		return result;
 	}
 	private transient Iterator<AbstractState> iterator;
 
@@ -77,6 +92,7 @@ public class StateMachine extends WorkListener
 			{
 				player.sendMessage("Installation done.");
 			}
+			finish();
 			return;
 		}
 		final AbstractState state = iterator.next();
@@ -86,6 +102,7 @@ public class StateMachine extends WorkListener
 	@Override
 	public void onWorkAbort(final String message)
 	{
+		finish();
 		Bukkit.getScheduler().scheduleSyncDelayedTask(getPlugin(), new Runnable()
 		{
 			@Override
@@ -115,4 +132,39 @@ public class StateMachine extends WorkListener
 			}
 		});
 	}
+
+	private void finish()
+	{
+		iterator = null;
+		states.clear();
+		getPlugin().getServer().getPluginManager().callEvent(new InstallationFinishedEvent());
+	}
+
+	public void resumeInstallation(Player player)
+	{
+		this.player = player;
+		if (result == MachineResult.WAIT)
+		{
+			if (current != null)
+			{
+				current.askQuestion(player);
+			}
+			else
+			{
+				throw new RuntimeException("State is WAIT, but current state is null!");
+			}
+		}
+		if (result == MachineResult.DONE && iterator != null)
+		{
+			player.sendMessage("Installation is still running.");
+		}
+		if (result == MachineResult.ABORT)
+		{
+			throw new RuntimeException("Player should not be able to resume a aborted installation.");
+		}
+		if (result == MachineResult.NONE)
+		{
+			throw new RuntimeException("State machine in an undefined state.");
+		}
+	}
 }