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: 69215 $ 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; 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 } else { 062 resolver = new ResolverUtil(); 063 } 064 } 065 066 public AnnotationTypeConverterLoader(ResolverUtil resolverUtil) { 067 this.resolver = resolverUtil; 068 } 069 070 public void load(TypeConverterRegistry registry) throws Exception { 071 String[] packageNames = findPackageNames(); 072 resolver.findAnnotated(Converter.class, packageNames); 073 Set<Class> classes = resolver.getClasses(); 074 for (Class type : classes) { 075 if (LOG.isDebugEnabled()) { 076 LOG.debug("Loading converter class: " + ObjectHelper.name(type)); 077 } 078 loadConverterMethods(registry, type); 079 } 080 } 081 082 /** 083 * Finds the names of the packages to search for on the classpath looking 084 * for text files on the classpath at the {@link #META_INF_SERVICES} location. 085 * 086 * @return a collection of packages to search for 087 * @throws IOException is thrown for IO related errors 088 */ 089 protected String[] findPackageNames() throws IOException { 090 Set<String> packages = new HashSet<String>(); 091 ClassLoader ccl = Thread.currentThread().getContextClassLoader(); 092 if (ccl != null) { 093 findPackages(packages, ccl); 094 } 095 findPackages(packages, getClass().getClassLoader()); 096 return packages.toArray(new String[packages.size()]); 097 } 098 099 protected void findPackages(Set<String> packages, ClassLoader classLoader) throws IOException { 100 Enumeration<URL> resources = classLoader.getResources(META_INF_SERVICES); 101 while (resources.hasMoreElements()) { 102 URL url = resources.nextElement(); 103 if (url != null) { 104 BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream())); 105 try { 106 while (true) { 107 String line = reader.readLine(); 108 if (line == null) { 109 break; 110 } 111 line = line.trim(); 112 if (line.startsWith("#") || line.length() == 0) { 113 continue; 114 } 115 tokenize(packages, line); 116 } 117 } finally { 118 ObjectHelper.close(reader, null, LOG); 119 } 120 } 121 } 122 } 123 124 /** 125 * Tokenizes the line from the META-IN/services file using commas and 126 * ignoring whitespace between packages 127 */ 128 protected void tokenize(Set<String> packages, String line) { 129 StringTokenizer iter = new StringTokenizer(line, ","); 130 while (iter.hasMoreTokens()) { 131 String name = iter.nextToken().trim(); 132 if (name.length() > 0) { 133 packages.add(name); 134 } 135 } 136 } 137 138 /** 139 * Loads all of the converter methods for the given type 140 */ 141 protected void loadConverterMethods(TypeConverterRegistry registry, Class type) { 142 if (visitedClasses.contains(type)) { 143 return; 144 } 145 visitedClasses.add(type); 146 try { 147 Method[] methods = type.getDeclaredMethods(); 148 CachingInjector injector = null; 149 150 for (Method method : methods) { 151 // this may be prone to ClassLoader or packaging problems when the same class is defined 152 // in two different jars (as is the case sometimes with specs). 153 if (ObjectHelper.hasAnnotation(method, Converter.class, true)) { 154 if (isValidConverterMethod(method)) { 155 int modifiers = method.getModifiers(); 156 if (isAbstract(modifiers) || !isPublic(modifiers)) { 157 LOG.warn("Ignoring bad converter on type: " + type.getName() + " method: " + method 158 + " as a converter method is not a public and concrete method"); 159 } else { 160 Class<?> toType = method.getReturnType(); 161 if (toType.equals(Void.class)) { 162 LOG.warn("Ignoring bad converter on type: " + type.getName() + " method: " 163 + method + " as a converter method returns a void method"); 164 } else { 165 Class<?> fromType = method.getParameterTypes()[0]; 166 if (isStatic(modifiers)) { 167 registerTypeConverter(registry, method, toType, fromType, 168 new StaticMethodTypeConverter(method)); 169 } else { 170 if (injector == null) { 171 injector = new CachingInjector(registry, type); 172 } 173 registerTypeConverter(registry, method, toType, fromType, 174 new InstanceMethodTypeConverter(injector, method)); 175 } 176 } 177 } 178 } else { 179 LOG.warn("Ignoring bad converter on type: " + type.getName() + " method: " + method 180 + " as a converter method should have one parameter"); 181 } 182 } 183 } 184 185 Class superclass = type.getSuperclass(); 186 if (superclass != null && !superclass.equals(Object.class)) { 187 loadConverterMethods(registry, superclass); 188 } 189 } catch (NoClassDefFoundError e) { 190 LOG.warn("Ignoring converter type: " + type.getName() + " as a dependent class could not be found: " + e, e); 191 } 192 } 193 194 protected void registerTypeConverter(TypeConverterRegistry registry, 195 Method method, Class toType, Class fromType, TypeConverter typeConverter) { 196 197 registry.addTypeConverter(toType, fromType, typeConverter); 198 } 199 200 protected boolean isValidConverterMethod(Method method) { 201 Class<?>[] parameterTypes = method.getParameterTypes(); 202 return (parameterTypes != null) && (parameterTypes.length == 1 203 || (parameterTypes.length == 2 && Exchange.class.isAssignableFrom(parameterTypes[1]))); 204 } 205 }