001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.camel.impl;
018    
019    import java.io.IOException;
020    import java.net.URL;
021    import java.util.Enumeration;
022    
023    /**
024     * WebSphere specific resolver to handle loading annotated resources in JAR files.
025     */
026    public class WebSpherePackageScanClassResolver extends DefaultPackageScanClassResolver {
027    
028        private final String resourcePath;
029    
030        /**
031         * Constructor.
032         *
033         * @param resourcePath  the fixed resource path to use for fetching camel jars in WebSphere.
034         */
035        public WebSpherePackageScanClassResolver(String resourcePath) {
036            this.resourcePath = resourcePath;
037        }
038    
039        /**
040         * Is the classloader from IBM and thus the WebSphere platform?
041         *
042         * @param loader  the classloader
043         * @return  <tt>true</tt> if IBM classloader, <tt>false</tt> otherwise.
044         */
045        public static boolean isWebSphereClassLoader(ClassLoader loader) {
046            return loader != null ? loader.getClass().getName().startsWith("com.ibm") : false;
047        }
048    
049        /**
050         * Overloaded to handle specific problem with getting resources on the IBM WebSphere platform.
051         * <p/>
052         * WebSphere can <b>not</b> load resources if the resource to load is a folder name, such as a
053         * packagename, you have to explicit name a resource that is a file.
054         *
055         * @param loader  the classloader
056         * @param packageName   the packagename for the package to load
057         * @return  URL's for the given package
058         * @throws java.io.IOException is thrown by the classloader
059         */
060        @Override
061        protected Enumeration<URL> getResources(ClassLoader loader, String packageName) throws IOException {
062            // try super first, just in vase
063            Enumeration<URL> enumeration = super.getResources(loader, packageName);
064            if (!enumeration.hasMoreElements()) {
065                log.trace("Using WebSphere workaround to load the camel jars with the annotated converters.");
066                // Special WebSphere trick to load a file that exists in the JAR and then let it go from there.
067                // The trick is that we just need the URL's for the .jars that contains the type
068                // converters that is annotated. So by searching for this resource WebSphere is able to find
069                // it and return the URL to the .jar file with the resource. Then the DefaultPackageScanClassResolver
070                // can take it from there and find the classes that are annotated.
071                enumeration = loader.getResources(resourcePath);
072            }
073    
074            return enumeration;
075        }
076    
077    }