jarclassloader.java

webwork source

package webwork.util.classloader;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.jar.JarFile;
import java.util.zip.ZipEntry;

import webwork.util.ClassLoaderUtils;

/**
 * User: Hani Suleiman
 * Date: Oct 22, 2003
 * Time: 3:56:56 PM
 */
public class JarClassLoader extends WebworkClassLoader
{
  private JarFile jar;
  private File file;
  private long jarLastModified;

  public JarClassLoader(File file, ClassLoader parent)
  {
    super(parent);
    this.file = file;
  }

  public boolean isStale()
  {
    return new File(jar.getName()).lastModified() > jarLastModified;
  }

  protected URL getDataURL(String name, byte[] data) throws MalformedURLException
  {
    return new URL(null, file.toURL().toExternalForm() + '!' + name, new BytesURLStreamHandler(data));
  }

  private void openJar() throws IOException
  {
    if(jar == null)
    {
      jar = new JarFile(file);
      jarLastModified = file.lastModified();
    }
  }

  public synchronized byte[] getFile(String path)
  {
    try
    {
      openJar();
      ZipEntry entry = jar.getEntry(path);

      if(entry == null) return null;
      InputStream in = jar.getInputStream(entry);
      int size = (int)entry.getSize();
      byte[] data = ClassLoaderUtils.readStream(in, size);
      return data;
    }
    catch(IOException e)
    {
      return null;
    }
  }

  public Object clone()
  {
    JarClassLoader loader = new JarClassLoader(file, getParent());
    loader.packages = packages;
    return loader;
  }
}