modelupdatenotifier.java

来自「《Java网络程序设计.rar》包括三个网络程序的源代码。」· Java 代码 · 共 58 行

/*

 */

package org.impact.stars.control.web;


import java.util.HashMap;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;

import org.impact.stars.util.Debug;
import org.impact.stars.control.exceptions.GeneralFailureException;
import org.impact.stars.control.exceptions.StarsAppException;

/**
 * This class is responsible for providing methods to add objects as listeners
 * for a particular model update event and for notifying the listeners when the
 * event actually occurs.
 */
public class ModelUpdateNotifier implements java.io.Serializable {

    private HashMap listenerMap;

    public ModelUpdateNotifier() {
        listenerMap = new HashMap();
    }

    public void notifyListeners(Collection updatedModelList) throws
                                                    StarsAppException {

        for (Iterator it1 = updatedModelList.iterator() ; it1.hasNext() ;) {
            String modelType = (String) it1.next();
            Debug.println("notifyListeners: " + modelType);
            Collection listeners = (Collection)listenerMap.get(modelType);
            if (listeners != null) {
                for (Iterator it2 = listeners.iterator(); it2.hasNext(); ) {
                    ((ModelUpdateListener) it2.next()).performUpdate();
                }
            }
        }
    }

    public void addListener(String modelType, Object listener) {

        Debug.println("Model update addlistener: " + modelType);
        if (listenerMap.get(modelType) == null) {
            ArrayList listeners = new ArrayList();
            listeners.add(listener);
            listenerMap.put(modelType,listeners);
        } else {
            ((ArrayList) listenerMap.get(modelType)).add(listener);
        }
    }
}