abstractgraph.java

来自「JPowerGraph is a Java library for creati」· Java 代码 · 共 85 行

package net.sourceforge.jpowergraph;

import java.util.Collection;
import java.util.EventListener;

import javax.swing.event.EventListenerList;

/**
 * An abstract base class for all graphs.
 */
public abstract class AbstractGraph implements Graph {
    /** The list of listeners. */
    protected EventListenerList m_listeners;

    /**
     * Creates a new graph.
     */
    public AbstractGraph() {
        m_listeners=new EventListenerList();
    }
    /**
     * Adds a listener to the graph.
     *
     * @param listener              the listener added to the graph
     */
    public void addGraphListener(GraphListener listener) {
        m_listeners.add(GraphListener.class,listener);
    }
    /**
     * Removes a listener from the graph.
     *
     * @param listener              the listener removed from the graph
     */
    public void removeGraphListener(GraphListener listener) {
        m_listeners.remove(GraphListener.class,listener);
    }
    /**
     * Notifies the graph that its elements have been updated.
     */
    public synchronized void notifyLayoutUpdated() {
        EventListener[] listeners=m_listeners.getListeners(GraphListener.class);
        for (int i=0;i<listeners.length;i++){
            ((GraphListener)listeners[i]).graphLayoutUpdated(this);
        }
    }
    /**
     * Notifies the graph that its nodes have been updated, but that no node has changed position.
     */
    public synchronized void notifyUpdated() {
        EventListener[] listeners=m_listeners.getListeners(GraphListener.class);
        for (int i=0;i<listeners.length;i++)
            ((GraphListener)listeners[i]).graphUpdated(this);
    }
    /**
     * Fires the graph contents changed event.
     */
    protected void fireGraphContentsChanged() {
        EventListener[] listeners=m_listeners.getListeners(GraphListener.class);
        for (int i=0;i<listeners.length;i++)
            ((GraphListener)listeners[i]).graphContentsChanged(this);
    }
    /**
     * Fires the elements added event.
     *
     * @param nodes                 the collection of nodes
     * @param edges                 the collection of edges
     */
    protected void fireElementsAdded(Collection nodes,Collection edges) {
        EventListener[] listeners=m_listeners.getListeners(GraphListener.class);
        for (int i=0;i<listeners.length;i++)
            ((GraphListener)listeners[i]).elementsAdded(this,nodes,edges);
    }
    /**
     * Fires the elements removed event.
     *
     * @param nodes                 the collection of nodes
     * @param edges                 the collection of edges
     */
    protected void fireElementsRemoved(Collection nodes,Collection edges) {
        EventListener[] listeners=m_listeners.getListeners(GraphListener.class);
        for (int i=0;i<listeners.length;i++)
            ((GraphListener)listeners[i]).elementsRemoved(this,nodes,edges);
    }
}