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.Exchange;
020    import org.apache.camel.impl.DefaultComponent;
021    import org.apache.commons.logging.Log;
022    import org.apache.commons.logging.LogFactory;
023    
024    import org.springframework.core.io.DefaultResourceLoader;
025    import org.springframework.core.io.Resource;
026    import org.springframework.core.io.ResourceLoader;
027    
028    /**
029     * A useful base class for components which depend on a resource
030     * such as things like Velocity or XQuery based components.
031     *
032     * @version $Revision: 673477 $
033     */
034    public abstract class ResourceBasedComponent extends DefaultComponent<Exchange> {
035        protected final transient Log log = LogFactory.getLog(getClass());
036        private ResourceLoader resourceLoader = new DefaultResourceLoader();
037    
038        public ResourceLoader getResourceLoader() {
039            return resourceLoader;
040        }
041    
042        public void setResourceLoader(ResourceLoader resourceLoader) {
043            this.resourceLoader = resourceLoader;
044        }
045    
046        protected Resource resolveMandatoryResource(String uri) {
047            Resource resource = getResourceLoader().getResource(uri);
048            if (resource == null) {
049                throw new IllegalArgumentException("Could not find resource for URI: " + uri + " using: " + getResourceLoader());
050            } else {
051                return resource;
052            }
053        }
054    
055    }