/* * ModuleLoader - A generic, policy-driven class loader. * Copyright (c) 2004, Richard S. Hall * 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 ungoverned.org 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. * * Contact: Richard S. Hall (heavy@ungoverned.org) * Contributor(s): ***/package org.ungoverned.moduleloader;import java.io.*;import java.util.jar.JarFile;import java.util.zip.ZipEntry;/** * <p> * This class implements a <tt>ResourceSource</tt> for retrieving resources * from a JAR file. The approach used by this implementation is to defer * opening the JAR file until a request for a resource is made. * </p> * @see org.ungoverned.moduleloader.ResourceSource**/public class JarResourceSource implements ResourceSource{    private static final int BUFSIZE = 4096;    private File m_file = null;    private JarFile m_jarFile = null;    private boolean m_opened = false;    /**     * <p>     * Constructs an instance using the specified file name as the source     * of the JAR file.     * </p>     * @param fileName the name of the JAR file to be used as the source.    **/    public JarResourceSource(String fileName)    {        m_file = new File(fileName);    }    /**     * <p>     * Constructs an instance using the specified file as the source     * of the JAR file.     * </p>     * @param file the JAR file to be used as the source.    **/    public JarResourceSource(File file)    {        m_file = file;    }    /**     * <p>     * Closes the JAR file if it has not already been closed.     * <p>    **/    protected void finalize()    {        if (m_jarFile != null)        {            try {                m_jarFile.close();            } catch (IOException ex) {                // Not much we can do, so ignore it.            }        }    }    /**     * <p>     * This method initializes the resource source. Since opening     * the JAR file is deferred until a request for a resource is     * actually made, this method really only sets a flag indicating     * that the resource source has been initialized.     * <p>    **/    public void open()    {        m_opened = true;    }    /**     * <p>     * This method deinitializes the resource source by closing     * the associated JAR file if it is open.     * <p>    **/    public synchronized void close()    {        try {            if (m_jarFile != null)            {                m_jarFile.close();            }        } catch (Exception ex) {            System.err.println("JarResourceSource: " + ex);        }        m_jarFile = null;        m_opened = false;    }    // JavaDoc comments are copied from ResourceSource.    public synchronized boolean hasResource(String name) throws IllegalStateException    {        if (!m_opened)        {            throw new IllegalStateException("JarResourceSource is not open");        }        // Open JAR file if not already opened.        if (m_jarFile == null)        {            try {                openJarFile();            } catch (IOException ex) {                System.err.println("JarResourceSource: " + ex);                return false;            }        }        try {            ZipEntry ze = m_jarFile.getEntry(name);            return ze != null;        } catch (Exception ex) {            return false;        } finally {        }    }    // JavaDoc comments are copied from ResourceSource.    public synchronized byte[] getBytes(String name) throws IllegalStateException    {        if (!m_opened)        {            throw new IllegalStateException("JarResourceSource is not open");        }        // Open JAR file if not already opened.        if (m_jarFile == null)        {            try {                openJarFile();            } catch (IOException ex) {                System.err.println("JarResourceSource: " + ex);                return null;            }        }        // Get the embedded resource.        InputStream is = null;        ByteArrayOutputStream baos = null;        try {            ZipEntry ze = m_jarFile.getEntry(name);            if (ze == null)            {                return null;            }            is = m_jarFile.getInputStream(ze);            if (is == null)            {                return null;            }            baos = new ByteArrayOutputStream(BUFSIZE);            byte[] buf = new byte[BUFSIZE];            int n = 0;            while ((n = is.read(buf, 0, buf.length)) >= 0)            {                baos.write(buf, 0, n);            }            return baos.toByteArray();        } catch (Exception ex) {            return null;        } finally {            try {                if (baos != null) baos.close();            } catch (Exception ex) {            }            try {                if (is != null) is.close();            } catch (Exception ex) {            }        }    }    private void openJarFile() throws IOException    {        if (m_jarFile == null)        {            m_jarFile = new JarFile(m_file);        }    }    public String toString()    {        return "JAR " + m_file.getPath();    }}