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: 65385 $ 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 findPackages(packages, Thread.currentThread().getContextClassLoader()); 092 findPackages(packages, getClass().getClassLoader()); 093 return packages.toArray(new String[packages.size()]); 094 } 095 096 protected void findPackages(Set<String> packages, ClassLoader classLoader) throws IOException { 097 Enumeration<URL> resources = classLoader.getResources(META_INF_SERVICES); 098 while (resources.hasMoreElements()) { 099 URL url = resources.nextElement(); 100 if (url != null) { 101 BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream())); 102 try { 103 while (true) { 104 String line = reader.readLine(); 105 if (line == null) { 106 break; 107 } 108 line = line.trim(); 109 if (line.startsWith("#") || line.length() == 0) { 110 continue; 111 } 112 tokenize(packages, line); 113 } 114 } finally { 115 ObjectHelper.close(reader, null, LOG); 116 } 117 } 118 } 119 } 120 121 /** 122 * Tokenizes the line from the META-IN/services file using commas and 123 * ignoring whitespace between packages 124 */ 125 protected void tokenize(Set<String> packages, String line) { 126 StringTokenizer iter = new StringTokenizer(line, ","); 127 while (iter.hasMoreTokens()) { 128 String name = iter.nextToken().trim(); 129 if (name.length() > 0) { 130 packages.add(name); 131 } 132 } 133 } 134 135 /** 136 * Loads all of the converter methods for the given type 137 */ 138 protected void loadConverterMethods(TypeConverterRegistry registry, Class type) { 139 if (visitedClasses.contains(type)) { 140 return; 141 } 142 visitedClasses.add(type); 143 try { 144 Method[] methods = type.getDeclaredMethods(); 145 CachingInjector injector = null; 146 147 for (Method method : methods) { 148 // this may be prone to ClassLoader or packaging problems when the same class is defined 149 // in two different jars (as is the case sometimes with specs). 150 if (ObjectHelper.hasAnnotation(method, Converter.class, true)) { 151 if (isValidConverterMethod(method)) { 152 int modifiers = method.getModifiers(); 153 if (isAbstract(modifiers) || !isPublic(modifiers)) { 154 LOG.warn("Ignoring bad converter on type: " + type.getName() + " method: " + method 155 + " as a converter method is not a public and concrete method"); 156 } else { 157 Class<?> toType = method.getReturnType(); 158 if (toType.equals(Void.class)) { 159 LOG.warn("Ignoring bad converter on type: " + type.getName() + " method: " 160 + method + " as a converter method returns a void method"); 161 } else { 162 Class<?> fromType = method.getParameterTypes()[0]; 163 if (isStatic(modifiers)) { 164 registerTypeConverter(registry, method, toType, fromType, 165 new StaticMethodTypeConverter(method)); 166 } else { 167 if (injector == null) { 168 injector = new CachingInjector(registry, type); 169 } 170 registerTypeConverter(registry, method, toType, fromType, 171 new InstanceMethodTypeConverter(injector, method)); 172 } 173 } 174 } 175 } else { 176 LOG.warn("Ignoring bad converter on type: " + type.getName() + " method: " + method 177 + " as a converter method should have one parameter"); 178 } 179 } 180 } 181 182 Class superclass = type.getSuperclass(); 183 if (superclass != null && !superclass.equals(Object.class)) { 184 loadConverterMethods(registry, superclass); 185 } 186 } catch (NoClassDefFoundError e) { 187 LOG.warn("Ignoring converter type: " + type.getName() + " as a dependent class could not be found: " + e, e); 188 } 189 } 190 191 protected void registerTypeConverter(TypeConverterRegistry registry, 192 Method method, Class toType, Class fromType, TypeConverter typeConverter) { 193 194 registry.addTypeConverter(toType, fromType, typeConverter); 195 } 196 197 protected boolean isValidConverterMethod(Method method) { 198 Class<?>[] parameterTypes = method.getParameterTypes(); 199 return (parameterTypes != null) && (parameterTypes.length == 1 200 || (parameterTypes.length == 2 && Exchange.class.isAssignableFrom(parameterTypes[1]))); 201 } 202 }