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.component;
018    
019    import org.apache.camel.impl.DefaultComponent;
020    import org.apache.commons.logging.Log;
021    import org.apache.commons.logging.LogFactory;
022    
023    import org.springframework.core.io.DefaultResourceLoader;
024    import org.springframework.core.io.Resource;
025    import org.springframework.core.io.ResourceLoader;
026    
027    /**
028     * A useful base class for components which depend on a resource
029     * such as things like Velocity or XQuery based components.
030     *
031     * @version $Revision: 743658 $
032     */
033    public abstract class ResourceBasedComponent extends DefaultComponent {
034        protected final transient Log log = LogFactory.getLog(getClass());
035        private ResourceLoader resourceLoader = new DefaultResourceLoader();
036    
037        public ResourceLoader getResourceLoader() {
038            return resourceLoader;
039        }
040    
041        public void setResourceLoader(ResourceLoader resourceLoader) {
042            this.resourceLoader = resourceLoader;
043        }
044    
045        protected Resource resolveMandatoryResource(String uri) {
046            Resource resource = getResourceLoader().getResource(uri);
047            if (resource == null) {
048                throw new IllegalArgumentException("Could not find resource for URI: " + uri + " using: " + getResourceLoader());
049            } else {
050                return resource;
051            }
052        }
053    
054    }