PluggableRobot/EventListener

/*
 * PluggableRobot, by Robert J. Walker
 * Home page: http://robowiki.net/cgi-bin/robowiki?PluggableRobot
 * This software is made available under the RoboWiki Limited Public Code License (RWLPCL). The full
 * text of the license may be found at http://robowiki.net/cgi-bin/robowiki?RWLPCL.
 */
package rjw.pluggablerobot;

import java.awt.Graphics2D;
import java.awt.geom.Point2D;
import java.util.ArrayList;

import robocode.*;

/**
 * A pluggable listener and strategy architecture for a robot.
 * http://robowiki.net/cgi-bin/robowiki?PluggableRobot
 * @author Robert J. Walker
 */
public abstract class PluggableRobot extends AdvancedRobot {
	private static boolean _battleInitialized = false;
	private static Hud _hud;

	private ListenerDelegate _listenerDelegate;
	private ArrayList<Component> _components;
	private ArrayList<Hud.Painter> _painters;
	private Point2D.Double _center;

	/**
	 * Sets up the ListenerDelegate and the Component and Painter lists.
	 */
	protected PluggableRobot() {
		_listenerDelegate = new ListenerDelegate();
		_components = new ArrayList<Component>();
		_painters = new ArrayList<Hud.Painter>();
	}

	/**
	 * Set up the robot, then continuously collect events and invoke components.
	 */
	@Override
	public final void run() {
		// Initialize battle (at start of first round only)
		if(!_battleInitialized) {
			_hud = new Hud(this);
			initializeBattle();
			_battleInitialized = true;
		}

		// Register custom event test() hook for event manager
		addCustomEvent(new Condition("eventManager") {
			public boolean test() {
				PluggableRobot.this.handleEvents();
				return false;
			}
		});

		// Round is starting
		initializeRound();

		// Main loop
		while(true) {
			for(Component component : _components) {
				component.go();
			}

			execute();
		}
	}

	/**
	 * This method will be called at the beginning of a battle. Robots can override this method to
	 * initialize their properties. This is a good place to initialize static properties or set your
	 * tank color.
	 */
	protected void initializeBattle() {
		// Default implementation does nothing
	}

	/**
	 * This method will be called at the beginning of each round. Robots can override this method to
	 * initialize their properties. This is a good place to set up non-static properties and
	 * register listeners, painters and components.
	 */
	protected void initializeRound() {
		// Default implementation does nothing
	}

	/**
	 * Called before events get processed each tick. The default implementation does nothing.
	 */
	public void onBeforeEventsProcessed() {
		// Do nothing
	}

	/**
	 * Returns a Point2D.Double object representing the center of the battlefield.
	 */
	public Point2D.Double getCenter() {
		if(_center == null) {
			_center = new Point2D.Double(getBattleFieldWidth() / 2, getBattleFieldHeight() / 2); 
		}

		return _center;
	}


	/**
	 * Registers the given EventListener, which will cause it to receive notifications of the events
	 * indicated by the listener interfaces it implements.
	 */
	protected void registerListener(EventListener listener) {
		_listenerDelegate.register(listener);
	}

	/**
	 * Reigsters the given Component, which will give it the opportunity to act each turn.
	 */
	protected void registerComponent(Component component) {
		_components.add(component);
	}

	/**
	 * Reigsters the given Painter, which will give it the opportunity to draw on the HUD each turn.
	 */
	protected void registerPainter(Hud.Painter painter) {
		_painters.add(painter);
	}

	/**
	 * Hand out notifications to the Painters.
	 */
	@Override
	public final void onPaint(Graphics2D g) {
		_hud.setContext(g); // Inject the graphics context into the Hud

		for(Hud.Painter painter : _painters) {
			painter.paint(_hud, getTime());
		}

		_hud.setContext(null); // Clear the injected graphics context
	}

	/**
	 * Process all the events in the queue.
	 */
	private void handleEvents() {
		onBeforeEventsProcessed();
		_listenerDelegate.processEvents(getAllEvents());
		clearAllEvents();
	}

	// Since we have our own event manager, we want to prevent overrides of the Robocode event
	// methods, so we'll make them final.

	@Override
	public final void onCustomEvent(CustomEvent event) {
	}

	@Override
	public final void onDeath(DeathEvent event) {
	}

	@Override
	public final void onSkippedTurn(SkippedTurnEvent event) {
	}

	@Override
	public final void onBulletHit(BulletHitEvent event) {
	}

	@Override
	public final void onBulletHitBullet(BulletHitBulletEvent event) {
	}

	@Override
	public final void onBulletMissed(BulletMissedEvent event) {
	}

	@Override
	public final void onHitByBullet(HitByBulletEvent event) {
	}

	@Override
	public final void onHitRobot(HitRobotEvent event) {
	}

	@Override
	public final void onHitWall(HitWallEvent event) {
	}

	@Override
	public final void onRobotDeath(RobotDeathEvent event) {
	}

	@Override
	public final void onScannedRobot(ScannedRobotEvent event) {
	}

	@Override
	public final void onWin(WinEvent event) {
	}
}