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package org.lcf.android.event;

import roboguice.event.javaassist.RuntimeSupport;
import roboguice.util.Ln;

import com.google.inject.Inject;
import com.google.inject.Singleton;

import java.lang.ref.WeakReference;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.*;

/**
 * Manager class handling the following:
 *
 *   Registration of event observing methods:
 *      registerObserver()
 *      unregisterObserver()
 *      clear()
 *   Raising Events:
 *      fire()
 *      notifyWithResult()
 *
 * @author Adam Tybor
 * @author John Ericksen
 * @author lazet
 */
@SuppressWarnings({"unchecked"})
@Singleton
public class EventManager {
    //@Inject protected android.content.Context context;

    protected Map> registrations = new HashMap>();

    /**
     * Register the given EventListener to the contest and event class.
     *
     * @param eventName observed
     * @param listener to be triggered
     */
    public void registerObserver( String eventName, EventListener listener ) {
        Set observers = registrations.get(eventName);
        if (observers == null) {
            observers = new LinkedHashSet();
            registrations.put(eventName, observers);
        }

        observers.add(listener);

    }

    /**
     * Registers given method with provided context and event.
     *
     * @param instance to be called
     * @param method to be called
     * @param eventName observed
     */
    public void registerObserver(Object instance, Method method, String eventName) {
        registerObserver(eventName, new ObserverMethodListener(instance, method));
    }

    /**
     * Unregisters the provided event listener from the given event
     *
     * @param eventName observed
     * @param listener to be unregistered

     */
    public  void unregisterObserver(String eventName, EventListener listener ) {

        final Set observers = registrations.get(eventName);
        if (observers == null) return;

        for (Iterator iterator = observers.iterator(); iterator.hasNext();) {
            final EventListener registeredListener = iterator.next();
            if (registeredListener == listener) {
                iterator.remove();
                break;
            }
        }
    }

    /**
     * Unregister all methods observing the given event from the provided context.
     *
     * @param instance to be unregistered
     * @param eventName observed
     */
    public  void unregisterObserver(Object instance, String eventName) {

        final Set observers = registrations.get(eventName);
        if (observers == null) return;

        for (Iterator iterator = observers.iterator(); iterator.hasNext();) {
            final EventListener listener = iterator.next();
            if( listener instanceof ObserverMethodListener ) {
                final ObserverMethodListener observer = ((ObserverMethodListener)listener);
                final Object registeredInstance = observer.instanceReference.get();
                if (registeredInstance == instance) {
                    iterator.remove();
                    break;
                }
            }
        }
    }

    /**
     * Raises the event's class' event on the given context.  This event object is passed (if configured) to the
     * registered observer's method.
     *
     * @param event observed
     */
    public void fire(Event event) {

        final Set observers = registrations.get(event.getName());
        if (observers == null) return;

        for (EventListener observer : observers){
        	try{
        		observer.onEvent(event);
        	}
        	catch(Exception e){
        		try{
        			this.unregisterObserver(event.getName(), observer);
        		}catch(Exception ee){
        			
        		}
        	}
        }
            

    }

    public static class ObserverMethodListener implements EventListener {
        protected String descriptor;
        protected Method method;
        protected WeakReference