yesnopanelmessageeditor.java

java 的164个例子的源代码,包括了 很多方面,供包括了19个方面的 源代码

/*
 * Copyright (c) 2000 David Flanagan.  All rights reserved.
 * This code is from the book Java Examples in a Nutshell, 2nd Edition.
 * It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied.
 * You may study, use, and modify it for any non-commercial purpose.
 * You may distribute it non-commercially as long as you retain this notice.
 * For a commercial use license, or to purchase the book (recommended),
 * visit http://www.davidflanagan.com/javaexamples2.
 */
package com.davidflanagan.examples.beans;
import java.beans.*;
import java.awt.*;
import java.awt.event.*;

/**
 * This class is a custom editor for the messageText property of the
 * YesNoPanel bean.  It is necessary because the default editor for
 * properties of type String does not allow multi-line strings
 * to be entered.
 */
public class YesNoPanelMessageEditor implements PropertyEditor {
    protected String value;  // The value we will be editing.
    
    public void setValue(Object o) {  value = (String) o; }
    public Object getValue() { return value; }
    public void setAsText(String s) { value = s; }
    public String getAsText() { return value; }
    public String[] getTags() { return null; }  // not enumerated; no tags
    
    // Say that we allow custom editing.
    public boolean supportsCustomEditor() { return true; }
    
    // Return the custom editor.  This just creates and returns a TextArea
    // to edit the multi-line text.  But it also registers a listener on the
    // text area to update the value as the user types and to fire the
    // property change events that property editors are required to fire.
    public Component getCustomEditor() {
	final TextArea t = new TextArea(value);
	t.setSize(300, 150); // TextArea has no preferred size, so set one
	t.addTextListener(new TextListener() {
		public void textValueChanged(TextEvent e) {
		    value = t.getText();
		    listeners.firePropertyChange(null, null, null);
		}
	    });
	return t;
    }
    
    // Visual display of the value, for use with the custom editor.
    // Just print some instructions and hope they fit in the in the box.
    // This could be more sophisticated.
    public boolean isPaintable() { return true; }
    public void paintValue(Graphics g, Rectangle r) {
	g.setClip(r);
	g.drawString("Click to edit...", r.x+5, r.y+15);
    }
    
    // Important method for code generators.  Note that it really ought to
    // escape any quotes or backslashes in value before returning the string.
    public String getJavaInitializationString() { return "\"" + value + "\""; }
    
    // This code uses the PropertyChangeSupport class to maintain a list of
    // listeners interested in the edits we make to the value.
    protected PropertyChangeSupport listeners =new PropertyChangeSupport(this);
    public void addPropertyChangeListener(PropertyChangeListener l) {
	listeners.addPropertyChangeListener(l);
    }
    public void removePropertyChangeListener(PropertyChangeListener l) {
	listeners.removePropertyChangeListener(l);
    }
}