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.converter; 018 019 import java.io.BufferedReader; 020 import java.io.IOException; 021 import java.io.InputStreamReader; 022 023 import java.lang.annotation.Annotation; 024 import java.lang.reflect.Method; 025 026 import java.net.URL; 027 import java.util.Enumeration; 028 import java.util.HashSet; 029 import java.util.Set; 030 import java.util.StringTokenizer; 031 import static java.lang.reflect.Modifier.isAbstract; 032 import static java.lang.reflect.Modifier.isPublic; 033 import static java.lang.reflect.Modifier.isStatic; 034 035 import org.apache.camel.Converter; 036 import org.apache.camel.Exchange; 037 import org.apache.camel.TypeConverter; 038 import org.apache.camel.util.ObjectHelper; 039 import org.apache.camel.util.ResolverUtil; 040 import org.apache.camel.util.WebSphereResolverUtil; 041 import org.apache.commons.logging.Log; 042 import org.apache.commons.logging.LogFactory; 043 044 /** 045 * A class which will auto-discover converter objects and methods to pre-load 046 * the registry of converters on startup 047 * 048 * @version $Revision: 56884 $ 049 */ 050 public class AnnotationTypeConverterLoader implements TypeConverterLoader { 051 public static final String META_INF_SERVICES = "META-INF/services/org/apache/camel/TypeConverter"; 052 private static final transient Log LOG = LogFactory.getLog(AnnotationTypeConverterLoader.class); 053 private ResolverUtil resolver = new ResolverUtil(); 054 private Set<Class> visitedClasses = new HashSet<Class>(); 055 056 public AnnotationTypeConverterLoader() { 057 // use WebSphere specific resolver if running on WebSphere 058 if (WebSphereResolverUtil.isWebSphereClassLoader(this.getClass().getClassLoader())) { 059 LOG.info("Using WebSphere specific ResolverUtil"); 060 resolver = new WebSphereResolverUtil(META_INF_SERVICES); 061 } 062 } 063 064 public void load(TypeConverterRegistry registry) throws Exception { 065 String[] packageNames = findPackageNames(); 066 resolver.findAnnotated(Converter.class, packageNames); 067 Set<Class> classes = resolver.getClasses(); 068 for (Class type : classes) { 069 if (LOG.isDebugEnabled()) { 070 LOG.debug("Loading converter class: " + ObjectHelper.name(type)); 071 } 072 loadConverterMethods(registry, type); 073 } 074 } 075 076 /** 077 * Finds the names of the packages to search for on the classpath looking 078 * for text files on the classpath at the {@link #META_INF_SERVICES} location. 079 * 080 * @return a collection of packages to search for 081 * @throws IOException is thrown for IO related errors 082 */ 083 protected String[] findPackageNames() throws IOException { 084 Set<String> packages = new HashSet<String>(); 085 findPackages(packages, Thread.currentThread().getContextClassLoader()); 086 findPackages(packages, getClass().getClassLoader()); 087 return packages.toArray(new String[packages.size()]); 088 } 089 090 protected void findPackages(Set<String> packages, ClassLoader classLoader) throws IOException { 091 Enumeration<URL> resources = classLoader.getResources(META_INF_SERVICES); 092 while (resources.hasMoreElements()) { 093 URL url = resources.nextElement(); 094 if (url != null) { 095 BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream())); 096 try { 097 while (true) { 098 String line = reader.readLine(); 099 if (line == null) { 100 break; 101 } 102 line = line.trim(); 103 if (line.startsWith("#") || line.length() == 0) { 104 continue; 105 } 106 tokenize(packages, line); 107 } 108 } finally { 109 ObjectHelper.close(reader, null, LOG); 110 } 111 } 112 } 113 } 114 115 /** 116 * Tokenizes the line from the META-IN/services file using commas and 117 * ignoring whitespace between packages 118 */ 119 protected void tokenize(Set<String> packages, String line) { 120 StringTokenizer iter = new StringTokenizer(line, ","); 121 while (iter.hasMoreTokens()) { 122 String name = iter.nextToken().trim(); 123 if (name.length() > 0) { 124 packages.add(name); 125 } 126 } 127 } 128 129 /** 130 * Loads all of the converter methods for the given type 131 */ 132 protected void loadConverterMethods(TypeConverterRegistry registry, Class type) { 133 if (visitedClasses.contains(type)) { 134 return; 135 } 136 visitedClasses.add(type); 137 try { 138 Method[] methods = type.getDeclaredMethods(); 139 CachingInjector injector = null; 140 141 for (Method method : methods) { 142 // this may be prone to ClassLoader or packaging problems when the same class is defined 143 // in two different jars (as is the case sometimes with specs). 144 if (ObjectHelper.hasAnnotation(method, Converter.class, true)) { 145 if (isValidConverterMethod(method)) { 146 int modifiers = method.getModifiers(); 147 if (isAbstract(modifiers) || !isPublic(modifiers)) { 148 LOG.warn("Ignoring bad converter on type: " + type.getName() + " method: " + method 149 + " as a converter method is not a public and concrete method"); 150 } else { 151 Class<?> toType = method.getReturnType(); 152 if (toType.equals(Void.class)) { 153 LOG.warn("Ignoring bad converter on type: " + type.getName() + " method: " 154 + method + " as a converter method returns a void method"); 155 } else { 156 Class<?> fromType = method.getParameterTypes()[0]; 157 if (isStatic(modifiers)) { 158 registerTypeConverter(registry, method, toType, fromType, 159 new StaticMethodTypeConverter(method)); 160 } else { 161 if (injector == null) { 162 injector = new CachingInjector(registry, type); 163 } 164 registerTypeConverter(registry, method, toType, fromType, 165 new InstanceMethodTypeConverter(injector, method)); 166 } 167 } 168 } 169 } else { 170 LOG.warn("Ignoring bad converter on type: " + type.getName() + " method: " + method 171 + " as a converter method should have one parameter"); 172 } 173 } 174 } 175 176 Class superclass = type.getSuperclass(); 177 if (superclass != null && !superclass.equals(Object.class)) { 178 loadConverterMethods(registry, superclass); 179 } 180 } catch (NoClassDefFoundError e) { 181 LOG.warn("Ignoring converter type: " + type.getName() + " as a dependent class could not be found: " + e, e); 182 } 183 } 184 185 protected void registerTypeConverter(TypeConverterRegistry registry, 186 Method method, Class toType, Class fromType, TypeConverter typeConverter) { 187 188 registry.addTypeConverter(toType, fromType, typeConverter); 189 } 190 191 protected boolean isValidConverterMethod(Method method) { 192 Class<?>[] parameterTypes = method.getParameterTypes(); 193 return (parameterTypes != null) && (parameterTypes.length == 1 194 || (parameterTypes.length == 2 && Exchange.class.isAssignableFrom(parameterTypes[1]))); 195 } 196 }