I decided to go with the simplest event model, based on message broad-cast. The fundamental principle is to have a central universal listener and receiver, all interested parties would hang-around this guy.
|--------|
| |
Sender1 -------\ | | |------ Listener 1
Sender2 --------\-----| Event- |------|------ Listener 2
Sender3 --------/-----| Bus |------|------ Listener 3
Sender4 -------/ | | |------ Listener 4
| |
|--------|
Sender
package org.myxyz.listeners;
//import com.google.gwt.event.shared.HandlerManager;
//import com.google.gwt.event.shared.HandlerRegistration;
import org.myxyz.custom.X10HandlerManager;
import org.myxyz.custom.X10HandlerRegistration;
public class MessageSender{
/**
*
*/
private static final long serialVersionUID = -382336739840212254L;
private MessageExchange exchange = MessageExchange.getMessageExchange();
private X10HandlerManager sender = null;
public MessageSender() {
sender = new X10HandlerManager(this);
X10HandlerRegistration handlerRegistration = sender.addHandler(MessageEvent.getType(), exchange);
exchange.registerSender(this, handlerRegistration);
}
/**
* Fire an event.
*/
public void fireEvent(MessageEvent event) {
sender.fireEvent(event);
}
}
|
MessageListener
package org.myxyz.listeners;
import com.google.gwt.event.shared.EventHandler;
public abstract class MessageListener<T> implements EventHandler{
private MessageExchange exchange = MessageExchange.getMessageExchange();
private T source = null;
public MessageListener(){
}
public MessageListener(T source){
exchange.addHandler(this);
this.source = source;
}
public T getSource(){
return source;
}
public abstract void messageRecieved(MessageEvent pEvent);
}
|
MessageEvent
package org.myxyz.listeners;
import org.myxyz.custom.X10GwtEvent;
//import com.google.gwt.event.shared.GwtEvent;
@SuppressWarnings("unchecked")
public class MessageEvent extends X10GwtEvent<MessageListener> {
private static final X10GwtEvent.Type<MessageListener> TYPE = new X10GwtEvent.Type<MessageListener>();
private String eventType = null;
private Object newValue = null;
private Object oldValue = null;
private Object source = null;
public static Type<MessageListener> getType() {
return TYPE;
}
public MessageEvent(String eventType) {
super();
this.eventType = eventType;
}
public MessageEvent(String eventType, Object oldValue, Object newValue) {
super();
this.eventType = eventType;
this.oldValue = oldValue;
this.newValue = newValue;
}
public MessageEvent(String eventType, Object oldValue, Object newValue, Object source) {
super();
this.eventType = eventType;
this.oldValue = oldValue;
this.newValue = newValue;
this.source = source;
}
@Override
protected void dispatch(MessageListener handler) {
handler.messageRecieved(this);
}
@Override
public Type<MessageListener> getAssociatedType() {
return TYPE;
}
public String getEventType() {
return eventType;
}
public Object getNewValue() {
return newValue;
}
public Object getOldValue() {
return oldValue;
}
public Object getSource() {
return source;
}
}
|
MessageExchange
package org.myxyz.listeners;
import java.util.HashMap;
import java.util.Iterator;
import com.google.gwt.event.shared.EventHandler;
import org.myxyz.custom.X10HandlerManager;
import org.myxyz.custom.X10HandlerRegistration;
@SuppressWarnings("unchecked")
public class MessageExchange extends MessageListener {
/**
*
*/
private static final long serialVersionUID = 1623583201346713682L;
private static final MessageExchange singleton = new MessageExchange();
private X10HandlerManager dispatcher = new X10HandlerManager(this);
private HashMap<MessageSender,X10HandlerRegistration> registeredSenders = new HashMap<MessageSender,X10HandlerRegistration>(10);
private HashMap<MessageListener,X10HandlerRegistration> registeredListeners = new HashMap<MessageListener,X10HandlerRegistration>(10);
public static MessageExchange getMessageExchange(){
return singleton;
}
private MessageExchange() {
}
public void messageRecieved(MessageEvent pEvent) {
dispatcher.fireEvent(pEvent);
}
public synchronized <H extends EventHandler> X10HandlerRegistration addHandler(MessageListener handler) {
X10HandlerRegistration handlerRegistration = registeredListeners.get(handler);
if(handlerRegistration == null) {
handlerRegistration = dispatcher.addHandler(MessageEvent.getType(), handler);
registeredListeners.put(handler, handlerRegistration);
}
return handlerRegistration;
}
public int getHandlerCount() {
return dispatcher.getHandlerCount(MessageEvent.getType());
}
public synchronized <H extends EventHandler> void removeHandler(MessageListener handler) {
if(registeredListeners.get(handler) != null){
registeredListeners.get(handler).removeHandler();
registeredListeners.remove(handler);
}
}
public synchronized void registerSender(MessageSender sender, X10HandlerRegistration handlerRegistration){
if(handlerRegistration != null) {
registeredSenders.put(sender, handlerRegistration);
}
}
public synchronized void unRegisterSender(MessageSender sender){
X10HandlerRegistration handlerRegistration = registeredSenders.get(sender);
if(handlerRegistration != null) {
handlerRegistration.removeHandler();
registeredSenders.remove(sender);
}
}
@Override
protected void finalize() throws Throwable {
for (Iterator<X10HandlerRegistration> iterator = registeredListeners.values().iterator(); iterator.hasNext();) {
X10HandlerRegistration handlerRegistration = iterator.next();
handlerRegistration.removeHandler();
}
for (Iterator<X10HandlerRegistration> iterator = registeredSenders.values().iterator(); iterator.hasNext();) {
X10HandlerRegistration handlerRegistration = iterator.next();
handlerRegistration.removeHandler();
}
}
}
|
Posts
No comments:
Post a Comment