resourceicon.java

这是linux下ssl vpn的实现程序

/*
 *  SSL-Explorer
 *
 *  Copyright (C) 2003-2006 3SP LTD. All Rights Reserved
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version 2 of
 *  the License, or (at your option) any later version.
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public
 *  License along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
			
package com.sshtools.ui.swing;

import java.net.URL;
import java.util.HashMap;
import java.awt.Image;
import java.awt.Toolkit;
import javax.swing.ImageIcon;

/**
 * Icon that can use a <code>Class</code> reference to determine a <code>ClassLoader</code>
 * to use to load an icon resource.
 * 
 * @author $Author: brett $
 * @version $Revision: 1.7 $
 */
public class ResourceIcon extends ImageIcon {
  //	Private instance variables
  private Class cls;

  private HashMap imageCache = new HashMap();

  public ResourceIcon(String image) {
    super();
    init(getClass(), image);
  }

  /**
   * Creates a new ResourceIcon given a class to derive the class loader from
   * and the image path.
   * 
   * @param cls class to derive class loader for image from
   * @param image image path
   */
  public ResourceIcon(Class cls, String image) {
    super();
    init(cls, image);
  }

  public void init(Class cls, String image) {
    this.cls = cls;
    if (image.startsWith("/")) {
      loadImage(image);
    } else {
      int idx = cls.getName().lastIndexOf('.');
      String packageName = idx == -1 ? null : cls.getName().substring(0, idx);
      String path = packageName == null ? "" : "/" + packageName;
      path = path.replace('.', '/');
      path += ("/" + image);
      loadImage(path);
    }
  }

  protected void loadImage(String imageName) {
    Image image = (Image) imageCache.get(imageName);
    if (image == null) {
      URL url = cls.getResource(imageName);
      if (url != null) {
        image = Toolkit.getDefaultToolkit().getImage(url);
      } else {
        url = cls.getClassLoader().getResource(imageName);
        if (url != null) {
          image = Toolkit.getDefaultToolkit().getImage(url);
        } else {
          image = Toolkit.getDefaultToolkit().getImage(imageName);
        }
      }
      imageCache.put(imageName, image);
    }
    if (image != null) {
      this.setImage(image);
    } else {
      System.err.println("null image?");
    }
  }
}