Refactored to make DiscoUpdater only call the update method on DiscoSheep and moved all the update logic to DiscoSheep.

src/gibstick/bukkit/discosheep/DiscoSheep.java

@@ -35,7 +35,7 @@ public final class DiscoSheep extends JavaPlugin {
 	private final int defaultSheepAmount = 10;
 	private final int defaultDuration = 1000;// ticks
 	private final int defaultFrequency = 20;// ticks per state change
-	
+	private int frequency = 0, duration = 0;
 
 	@Override
 	public void onEnable() {
@@ -105,22 +105,32 @@ public final class DiscoSheep extends JavaPlugin {
 		//TODO: Add sound playing here
 	}
 
-	//	Called after discosheep is stopped
-	void cleanUp() {
-		removeAllSheep();
-		this.playerArray.clear();
+	void update() {
+		if (duration > 0) {
+			randomizeSheepColours();
+			playSounds();
+			duration -= frequency;
+			this.scheduleUpdate();
+		} else {
+			this.stopDisco();
+		}
 	}
 
 	void scheduleUpdate() {
-		updater.runTaskLater(this, updater.frequency);
+		new DiscoUpdater(this).runTaskLater(this, this.frequency);
 	}
 
 	void startDisco(int duration, List<Player> players) {
+		if(this.duration > 0){
+			stopDisco();
+		}
 		this.playerArray.addAll(players);
 		for(Player player : players){
 			this.spawnSheep(player, this.defaultSheepAmount);
 		}
-		updater.start(duration,this.defaultFrequency);
+		this.frequency = this.defaultFrequency;
+		this.duration = this.defaultDuration;
+		this.scheduleUpdate();
 	}
 
 	void startDisco(List<Player> players) {
@@ -128,6 +138,8 @@ public final class DiscoSheep extends JavaPlugin {
 	}
 
 	void stopDisco() {
-		updater.stop();
+		removeAllSheep();
+		this.playerArray.clear();
+		this.duration = 0;
 	}
 }

src/gibstick/bukkit/discosheep/DiscoUpdater.java

@@ -4,33 +4,14 @@ import org.bukkit.scheduler.BukkitRunnable;
 
 public class DiscoUpdater extends BukkitRunnable {
 
-	int frequency = 0, duration = 0;
 	private DiscoSheep parent;
 
 	public DiscoUpdater(DiscoSheep parent) {
 		this.parent = parent;
 	}
 
-	public void stop() {
-		this.duration = 0;
-		parent.cleanUp();
-	}
-	
-	public void start(int duration, int frequency) {
-		this.frequency = frequency;
-		this.duration = duration;
-		parent.scheduleUpdate();
-	}
-
 	@Override
 	public void run() {
-		if (duration > 0) {
-			parent.randomizeSheepColours();
-			parent.playSounds();
-			duration -= frequency;
-			parent.scheduleUpdate();
-		} else {
-			this.stop();
-		}
+		parent.update();
 	}
 }