de.intarsys.tools.event.EventDispatcher Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of isrt Show documentation
The basic runtime tools and interfaces for intarsys components.
There is a newer version: 4.11
/*
 * Copyright (c) 2007, intarsys consulting GmbH
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 *
 * - Neither the name of intarsys nor the names of its contributors may be used
 *   to endorse or promote products derived from this software without specific
 *   prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package de.intarsys.tools.event;

import java.io.Serializable;

/**
 * Helper object for management and dispatching of events.
 */
public class EventDispatcher implements INotificationSupport,
		INotificationListener, Serializable {

	/** The owner originating the events */
	private final Object owner;

	private EventType[] types = new EventType[4];

	private INotificationListener[] listeners = new INotificationListener[4];

	public EventDispatcher(Object pOwner) {
		super();
		owner = pOwner;
	}

	public synchronized void addNotificationListener(EventType type,
			INotificationListener listener) {
		if (listener == null) {
			throw new NullPointerException("listener may not be null");
		}
		// if (hasListener(type, listener)) {
		// // debug code
		// toString();
		// }
		int length = listeners.length;
		int i = 0;
		while (i < length) {
			if (listeners[i] == null) {
				break;
			}
			i++;
		}
		if (i >= length) {
			INotificationListener[] tempListeners = new INotificationListener[length + 4];
			System.arraycopy(listeners, 0, tempListeners, 0, length);
			listeners = tempListeners;
			EventType[] tempIds = new EventType[length + 4];
			System.arraycopy(types, 0, tempIds, 0, length);
			types = tempIds;
		}
		types[i] = type;
		listeners[i] = listener;
	}

	synchronized public void attach(INotificationSupport support) {
		int length = listeners.length;
		for (int i = 0; i < length; i++) {
			EventType tempType = types[i];
			if (tempType != null) {
				support.addNotificationListener(tempType, listeners[i]);
			}
		}
	}

	public synchronized void clear() {
		types = new EventType[4];
		listeners = new INotificationListener[4];
	}

	synchronized public void detach(INotificationSupport support) {
		int length = listeners.length;
		for (int i = 0; i < length; i++) {
			EventType tempType = types[i];
			if (tempType != null) {
				support.removeNotificationListener(tempType, listeners[i]);
			}
		}
	}

	public Object getOwner() {
		return owner;
	}

	public void handleEvent(Event event) {
		Object typeId = event.getEventType();
		int length = listeners.length;
		for (int i = 0; i < length; i++) {
			Object id = types[i];
			if (id != typeId && id != EventType.ALWAYS) {
				continue;
			}
			listeners[i].handleEvent(event);
		}
	}

	protected boolean hasListener(EventType type, INotificationListener listener) {
		int length = listeners.length;
		int i = 0;
		while (i < length) {
			if (types[i] == type && listeners[i] == listener) {
				return true;
			}
			i++;
		}
		return false;
	}

	public synchronized boolean isEmpty() {
		for (int i = 0; i < listeners.length; i++) {
			if (listeners[i] != null) {
				return false;
			}
		}
		return true;
	}

	public synchronized void removeNotificationListener(EventType type,
			INotificationListener listener) {
		int length = listeners.length;
		int i = 0;
		while (i < length) {
			if (types[i] == type && listeners[i] == listener) {
				types[i] = null;
				listeners[i] = null;
				break;
			}
			i++;
		}
	}

	public void triggerEvent(Event event) {
		handleEvent(event);
	}

	public void triggerEventReverse(Event event) {
		Object typeId = event.getEventType();
		for (int i = listeners.length; i >= 0; i--) {
			Object id = types[i];
			if (id != typeId && id != EventType.ALWAYS) {
				continue;
			}
			listeners[i].handleEvent(event);
		}
	}
}