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
021 import org.apache.camel.CamelContext;
022 import org.apache.camel.NoFactoryAvailableException;
023 import org.apache.camel.NoSuchLanguageException;
024 import org.apache.camel.spi.Language;
025 import org.apache.camel.spi.LanguageResolver;
026 import org.apache.camel.util.FactoryFinder;
027 import org.apache.commons.logging.Log;
028 import org.apache.commons.logging.LogFactory;
029
030 /**
031 * Default language resolver that looks for language factories in <b>META-INF/services/org/apache/camel/language/</b> and
032 * language resolvers in <b>META-INF/services/org/apache/camel/language/resolver/</b>.
033 *
034 * @version $Revision: 752893 $
035 */
036 public class DefaultLanguageResolver implements LanguageResolver {
037 protected static final FactoryFinder LANGUAGE_FACTORY = new FactoryFinder("META-INF/services/org/apache/camel/language/");
038 protected static final FactoryFinder LANGUAGE_RESOLVER = new FactoryFinder("META-INF/services/org/apache/camel/language/resolver/");
039 private static final transient Log LOG = LogFactory.getLog(DefaultLanguageResolver.class);
040
041 protected Log getLog() {
042 return LOG;
043 }
044
045 @SuppressWarnings("unchecked")
046 public Language resolveLanguage(String name, CamelContext context) {
047 Object bean = null;
048 try {
049 bean = context.getRegistry().lookup(name);
050 if (bean != null && getLog().isDebugEnabled()) {
051 getLog().debug("Found language: " + name + " in registry: " + bean);
052 }
053 } catch (Exception e) {
054 getLog().debug("Ignored error looking up bean: " + name + ". Error: " + e);
055 }
056 if (bean != null) {
057 if (bean instanceof Language) {
058 return (Language)bean;
059 }
060 // we do not throw the exception here and try to auto create a Language from META-INF
061 }
062 Class type = null;
063 try {
064 type = findLanguage(name);
065 } catch (NoFactoryAvailableException e) {
066 // ignore
067 } catch (Exception e) {
068 throw new IllegalArgumentException("Invalid URI, no Language registered for scheme: " + name, e);
069 }
070 if (type != null) {
071 if (Language.class.isAssignableFrom(type)) {
072 return (Language)context.getInjector().newInstance(type);
073 } else {
074 throw new IllegalArgumentException("Type is not a Language implementation. Found: " + type.getName());
075 }
076 }
077 return noSpecificLanguageFound(name, context);
078 }
079
080 @SuppressWarnings("unchecked")
081 protected Language noSpecificLanguageFound(String name, CamelContext context) {
082 Class type = null;
083 try {
084 type = findLanguageResolver("default");
085 } catch (NoFactoryAvailableException e) {
086 // ignore
087 } catch (Exception e) {
088 throw new IllegalArgumentException("Invalid URI, no Language registered for scheme: " + name, e);
089 }
090 if (type != null) {
091 if (LanguageResolver.class.isAssignableFrom(type)) {
092 LanguageResolver resolver = (LanguageResolver)context.getInjector().newInstance(type);
093 return resolver.resolveLanguage(name, context);
094 } else {
095 throw new IllegalArgumentException("Type is not a LanguageResolver implementation. Found: " + type.getName());
096 }
097 }
098 throw new NoSuchLanguageException(name);
099 }
100
101 protected Class findLanguage(String name) throws Exception {
102 return LANGUAGE_FACTORY.findClass(name);
103 }
104
105 protected Class findLanguageResolver(String name) throws Exception {
106 return LANGUAGE_RESOLVER.findClass("default");
107 }
108 }