uk.org.retep.util.classloader.JarClassLoader Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of j2ee Show documentation
There is a newer version: 10.6
/*
 * Copyright (c) 1998-2007, Peter T Mount

 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 
 *   Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 *   Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 *   Neither the name of the retep.org.uk nor the names of its contributors
 *   may be used to endorse or promote products derived from this software
 *   without specific prior written permission.
 *
 * 
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package uk.org.retep.util.classloader;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.jar.JarFile;
import java.util.zip.ZipEntry;
import uk.org.retep.util.io.FileUtils;

/**
 * A ClassLoader that will load classes from a single JAR.
 * 
 * @author peter
 */
public class JarClassLoader
        extends CachingInputStreamClassLoader
{

    private JarFile jarFile;

    public JarClassLoader( final String jar )
            throws IOException
    {
        this( new File( jar ) );
    }

    public JarClassLoader( final File jar )
            throws IOException
    {
        super();
        jarFile = new JarFile( jar );
    }

    public JarClassLoader( final String jar,
                           final ClassLoader parent )
            throws IOException
    {
        super( parent );
        jarFile = new JarFile( jar );
    }

    public JarClassLoader( final File jar, final ClassLoader parent )
            throws IOException
    {
        super( parent );
        jarFile = new JarFile( jar );
    }

    public void close()
            throws IOException
    {
        jarFile.close();
    }

    private String fixName( final String classname )
    {
        return classname.replace( '.', '/' ) + ".class";
    }

    @Override
    protected byte[] readBytes( final String className )
            throws IOException
    {
        final ZipEntry entry = jarFile.getEntry( fixName( className ) );

        return FileUtils.readBytes( jarFile.getInputStream( entry ) );
    }

    @Override
    protected URL findResource( final String name )
    {
        // Not currently supported
        return null;
    }
}