org.apache.velocity.runtime.resource.loader.JarResourceLoader Maven / Gradle / Ivy

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package org.apache.velocity.runtime.resource.loader;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.    
 */

import java.io.InputStream;

import java.util.Hashtable;
import java.util.Vector;
import java.util.Map;
import java.util.HashMap;

import org.apache.velocity.util.StringUtils;
import org.apache.velocity.runtime.resource.Resource;
import org.apache.velocity.exception.ResourceNotFoundException;
import org.apache.commons.collections.ExtendedProperties;

/**
 * 
 * ResourceLoader to load templates from multiple Jar files.
 * 
 * 
 * The configuration of the JarResourceLoader is straightforward -
 * You simply add the JarResourceLoader to the configuration via
 * 
 * 
 *    resource.loader = jar
 *    jar.resource.loader.class = org.apache.velocity.runtime.resource.loader.JarResourceLoader
 *    jar.resource.loader.path = list of JAR <URL>s
 * 

 *
 *  So for example, if you had a jar file on your local filesystem, you could simply do
 *    
 *    jar.resource.loader.path = jar:file:/opt/myfiles/jar1.jar
 *    
 * 
 *  Note that jar specification for the .path configuration property
 * conforms to the same rules for the java.net.JarUrlConnection class.
 * 
 *
 *  For a working example, see the unit test case,
 *  org.apache.velocity.test.MultiLoaderTestCase class
 * 
 *
 * @author Aki Nieminen
 * @author Dave Bryson
 * @version $Id: JarResourceLoader.java 691884 2008-09-04 06:46:51Z nbubna $
 */
public class JarResourceLoader extends ResourceLoader
{
    /**
     * Maps entries to the parent JAR File
     * Key = the entry *excluding* plain directories
     * Value = the JAR URL
     */
    private Map entryDirectory = new HashMap(559);

    /**
     * Maps JAR URLs to the actual JAR
     * Key = the JAR URL
     * Value = the JAR
     */
    private Map jarfiles = new HashMap(89);

    /**
     * Called by Velocity to initialize the loader
     * @param configuration
     */
    public void init( ExtendedProperties configuration)
    {
        log.trace("JarResourceLoader : initialization starting.");

        // rest of Velocity engine still use legacy Vector
        // and Hashtable classes. Classes are implicitly
        // synchronized even if we don't need it.
        Vector paths = configuration.getVector("path");
        StringUtils.trimStrings(paths);

        /*
         *  support the old version but deprecate with a log message
         */

        if( paths == null || paths.size() == 0)
        {
            paths = configuration.getVector("resource.path");
            StringUtils.trimStrings(paths);

            if (paths != null && paths.size() > 0)
            {
                log.debug("JarResourceLoader : you are using a deprecated configuration"
                          + " property for the JarResourceLoader -> '.resource.loader.resource.path'."
                          + " Please change to the conventional '.resource.loader.path'.");
            }
        }

        if (paths != null)
        {
            log.debug("JarResourceLoader # of paths : " + paths.size() );

            for ( int i=0; i