/*

  * ====================================================================

  *

  * The Apache Software License, Version 1.1

  *

  * Copyright (c) 1999 The Apache Software Foundation.  All rights 

  * reserved.

  *

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted provided that the following conditions

  * are met:

  *

  * 1. Redistributions of source code must retain the above copyright

  *    notice, this list of conditions and the following disclaimer. 

  *

  * 2. 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.

  *

  * 3. The end-user documentation included with the redistribution, if

  *    any, must include the following acknowlegement:  

  *       "This product includes software developed by the 

  *        Apache Software Foundation (http://www.apache.org/)."

  *    Alternately, this acknowlegement may appear in the software itself,

  *    if and wherever such third-party acknowlegements normally appear.

  *

  * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software

  *    Foundation" must not be used to endorse or promote products derived

  *    from this software without prior written permission. For written 

  *    permission, please contact apache@apache.org.

  *

  * 5. Products derived from this software may not be called "Apache"

  *    nor may "Apache" appear in their names without prior written

  *    permission of the Apache Group.

  *

  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR

  * ITS 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 net.wotonomy.foundation.internal;

 import java.io.ByteArrayOutputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import java.net.URL;

 import java.util.Enumeration;

 import java.util.Hashtable;

 import java.util.zip.ZipEntry;

 import java.util.zip.ZipInputStream;

 /**

  * This implementation of URL Resource Reader assumes 2 types

  * of base urls. A base url that ends with / is considered a

  * resource folder, whereas a resource that does not end with

  * / is considered a zip/jar resource folder.

  *

  * If the resource folder happens is a zip/jar archive, the

  * entries are always cached.

  * For non-zip base urls, one could specify whether or not it should

  * be cached.

  *

  * @author Harish Prabandham

  */

 public class URLResourceReader  {

     private Hashtable resourceCache = new Hashtable();

     private boolean iszip = true;

     private URL url = null;

     private boolean cache = true;

     /**

      * Creates a new URLResourceReader object. You can either give

      * the URL of the zip/jar file or a base url where to

      * look for additional resources. If the url ends with

      * "/" then it is assumed to be  a Base URL. 

      * @param The base url to look for the resources.

      * @param If the base url is not a zip/jar, then true indicates

      * that entries should be cached, false otherwise.

      */

     public URLResourceReader(URL baseurl, boolean cache) throws IOException {

         this.url = baseurl;

         this.cache = cache;

         this.iszip = !url.getFile().endsWith("/");

         if(this.iszip)

             this.cache = true;

         initialize();

     }

     /**

      * equivalent to URLResourceReader(baseurl, false)

      */

     public URLResourceReader(URL baseurl) throws IOException {

         this(baseurl, false);

     }

     /**

      * Creates a new URLResourceReader object with the given

      * input stream. The stream is assumed to be a zip/jar

      * stream.

      */

     public URLResourceReader(InputStream is) throws IOException {

         init(is);

     }

     private void initialize() throws IOException {

         if(iszip) {

             InputStream is = url.openStream();

             init(is);

             is.close();

         }

     }

     private byte[] readFully(InputStream is) throws IOException {

         byte[] buf = new byte[1024];

         int num = 0;

         ByteArrayOutputStream bout = new ByteArrayOutputStream();

         while( (num = is.read(buf)) != -1) {

             bout.write(buf, 0, num);

         }

         return bout.toByteArray();

     }

     private void init(InputStream is) throws IOException {

         ZipInputStream zstream = new ZipInputStream(is);

         ZipEntry entry;

         while( (entry = zstream.getNextEntry()) != null) {

             byte[] entryData = readFully(zstream);

             if(cache)

                 resourceCache.put(entry.getName(), entryData);

             zstream.closeEntry();

         }

         zstream.close();

     }

     /**

      * Returns an Enumeration of all "known" resource names.

      */

     public Enumeration getResourceNames() {

         return resourceCache.keys();

     }

     /**

      * Returns an array of bytes read for this resource if the

      * resource exists. This method blocks until the resource

      * has been fully read. If the resource does not exist,

      * this method returns null.

      */

     public byte[] getResource(String  resource) {

         // lookup the data in the cache...

         byte[] data = (byte[]) resourceCache.get(resource);

         if(data != null) {

             return data;

         }

         // if the data was to come from a zip file that we

         // already read fully & cached , then it is probably

         // not there.

         if(iszip) {

             return null;

         }

         // Now the only choice left is to make a url connection.

         try {

             URL realURL = new URL(url.getProtocol(), url.getHost(),

                                   url.getFile() + resource);

             data = readFully(realURL.openStream());

             // add it to cache if needed...

             if(cache)

                 resourceCache.put(resource, data);

             return data;

         } catch(Exception e) {

             return null;

         }

     }

     public void close() {

         resourceCache.clear();

         resourceCache = null;

     }

     public String toString() {

         return url.toString();

     }

 }