001    /**
002     *
003     * Licensed to the Apache Software Foundation (ASF) under one or more
004     * contributor license agreements.  See the NOTICE file distributed with
005     * this work for additional information regarding copyright ownership.
006     * The ASF licenses this file to You under the Apache License, Version 2.0
007     * (the "License"); you may not use this file except in compliance with
008     * the License.  You may obtain a copy of the License at
009     *
010     * http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    package org.apache.camel.impl;
019    
020    import org.apache.camel.CamelContext;
021    import org.apache.camel.Component;
022    import org.apache.camel.Exchange;
023    import org.apache.camel.spi.ComponentResolver;
024    import org.apache.camel.util.FactoryFinder;
025    import org.apache.camel.util.NoFactoryAvailableException;
026    
027    /**
028     * The default implementation of {@link ComponentResolver}
029     * which tries to find components by using the URI scheme prefix and searching for a file of the URI
030     * scheme name in the <b>META-INF/services/org/apache/camel/component/</b>
031     * directory on the classpath.
032     *
033     * @version $Revision: 530555 $
034     */
035    public class DefaultComponentResolver<E extends Exchange> implements ComponentResolver<E> {
036        protected static final FactoryFinder componentFactory = new FactoryFinder("META-INF/services/org/apache/camel/component/");
037    
038        public Component<E> resolveComponent(String name, CamelContext context) {
039            Class type;
040            try {
041                type = componentFactory.findClass(name);
042            }
043            catch (NoFactoryAvailableException e) {
044                return null;
045            }
046            catch (Throwable e) {
047                throw new IllegalArgumentException("Invalid URI, no EndpointResolver registered for scheme : " + name, e);
048            }
049            if (type == null) {
050                return null;
051            }
052            if (Component.class.isAssignableFrom(type)) {
053                return (Component<E>)context.getInjector().newInstance(type);
054            }
055            else {
056                throw new IllegalArgumentException("Type is not a Component implementation. Found: " + type.getName());
057            }
058        }
059    }