Application: gvSIG desktop » Library: org.gvsig.tools

package org.gvsig.tools.util;

import java.util.EventListener;

import java.util.HashSet;

import java.util.Set;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

public class BaseListenerSupport {

    protected static final Logger LOGGER = LoggerFactory.getLogger(BaseListenerSupport.class);

    public interface NotificationListener extends EventListener {

        public void notify(EventListener event);

    }

    protected Set<EventListener> listeners = new HashSet();

    public void addListener(EventListener listener) {

        listeners.add(listener);

    }

    public EventListener[] getListeners() {

        return (EventListener[]) this.listeners.toArray(new EventListener[this.listeners.size()]);

    }

    public boolean hasListeners() {

        return !this.listeners.isEmpty();

    }

    public void removeListener(EventListener listener) {

        listeners.remove(listener);

    }

    public void removeAllListener() {

        this.listeners.clear();

    }

    public void notifyEvent(EventListener event) {

        for (EventListener listener : this.listeners) {

            if( listener instanceof NotificationListener ) {

                try {

                    ((NotificationListener)listener).notify(event);

                } catch(Throwable th) {

                    LOGGER.warn("Problems notifying "+(event==null? "NULL":event.getClass().getSimpleName())+" to "+listener.getClass().getSimpleName());

                }

            }

        }

    }

}