indexedtest.java

jdk-6u10-docs java开发宝典

import java.beans.IndexedPropertyChangeEvent;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;

import java.awt.Color;

/**
 * Illustrates the basic functionality of IndexedPropertyChangeEvent and the 
 * fireIndexed... methods on PropertyChangeSupport.
 * <p>
 * An IndexedPropertyChangeEvent extends the PropertyChangeEvent by adding the
 * index of the property which fired the event. 
 */
public class IndexedTest  {

    /**
     * This class represent a souce of IndexedPropertyChangeEvents
     * When an indexed property change, the fireIndexedPropertyChange
     * method should be called.
     */
    public static class IndexedSource {

	private PropertyChangeSupport changeSupport;

	// fields
	private Color color;
	private boolean bool;
	private int ival;

	public IndexedSource() {
	    changeSupport = new PropertyChangeSupport(this);
	}

	// Object indexed property
	public void setColor(int index, Color color) {
	    Color oldColor = this.color;
	    this.color = color;
	    changeSupport.fireIndexedPropertyChange("color", index,
						    oldColor, color);
	}

	// boolean indexed property
	public void setBoolean(int index, boolean bool) {
	    boolean oldBool = this.bool;
	    this.bool = bool;
	    changeSupport.fireIndexedPropertyChange("boolean", index,
						    oldBool, bool);
	}

	// int indexed property
	public void setInteger(int index, int ival) {
	    int oldInt = this.ival;
	    this.ival = ival;
	    changeSupport.fireIndexedPropertyChange("integer", index,
						    oldInt, ival);
	}

	/**
	 * Listener registration method. Should also implement
	 * remove and get listener methods to be complete.
	 */
	public void addPropertyChangeListener(PropertyChangeListener l) {
	    changeSupport.addPropertyChangeListener(l);
	}
    }

    /**
     * This class represents a listener of PropertyChangeEvents.
     * The new indexed property change notification is compatible with
     * existing property change listeners.
     * <p>
     * If the listener is expecting IndexedPropertyChangeEvents, then 
     * the PropertyChangeEvent should be checked.
     */
    public static class IndexedListener implements PropertyChangeListener {

	public void propertyChange(PropertyChangeEvent evt) {
	    String propertyName = evt.getPropertyName();
	
	    // Support for indexed properties?
	    int index = -1;
	    if (evt instanceof IndexedPropertyChangeEvent) {
		index = ((IndexedPropertyChangeEvent)evt).getIndex();
	    }
	    System.out.println("Property: " + propertyName + " index: " + index + 
			       " value: " + evt.getNewValue());
	}
    }
    
    public static void main(String[] args) throws Exception {
	IndexedSource source = new IndexedSource();
	source.addPropertyChangeListener(new IndexedListener());

	for (int i = 0; i < 5; i++) {
	    source.setColor(i, (i % 2 == 0) ? Color.red : Color.blue);
	    source.setBoolean(i, (i % 2 == 0) ? true : false);
	    source.setInteger(i, i);
	}
    }
}