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.spring.util;
018
019 import org.aopalliance.intercept.MethodInvocation;
020 import org.apache.camel.Body;
021 import org.apache.camel.Exchange;
022 import org.apache.camel.Expression;
023 import org.apache.camel.Header;
024 import org.apache.camel.Property;
025 import org.apache.camel.RuntimeCamelException;
026 import org.apache.camel.builder.ExpressionBuilder;
027 import org.apache.commons.logging.Log;
028 import org.apache.commons.logging.LogFactory;
029
030 import java.lang.annotation.Annotation;
031 import java.lang.reflect.Method;
032 import java.util.Arrays;
033 import java.util.Collection;
034 import java.util.Map;
035 import java.util.concurrent.ConcurrentHashMap;
036
037 /**
038 * Represents the metadata about a bean type created via a combination of
039 * introspection and annotations together with some useful sensible defaults
040 *
041 * @version $Revision: $
042 */
043 public class BeanInfo {
044 private static final transient Log log = LogFactory.getLog(BeanInfo.class);
045 private Class type;
046 private MethodInvocationStrategy strategy;
047 private Map<String, MethodInfo> operations = new ConcurrentHashMap<String, MethodInfo>();
048 private MethodInfo defaultExpression;
049
050 public BeanInfo(Class type, MethodInvocationStrategy strategy) {
051 this.type = type;
052 this.strategy = strategy;
053 }
054
055 public Class getType() {
056 return type;
057 }
058
059 public void introspect() {
060 introspect(getType());
061 if (operations.size() == 1) {
062 Collection<MethodInfo> methodInfos = operations.values();
063 for (MethodInfo methodInfo : methodInfos) {
064 defaultExpression = methodInfo;
065 }
066 }
067 }
068
069 public MethodInvocation createInvocation(Method method, Object pojo, Exchange messageExchange) throws RuntimeCamelException {
070 MethodInfo methodInfo = introspect(type, method);
071 return methodInfo.createMethodInvocation(pojo, messageExchange);
072 }
073
074 public MethodInvocation createInvocation(Object pojo, Exchange messageExchange) throws RuntimeCamelException {
075 MethodInfo methodInfo = null;
076
077 // TODO use some other mechanism?
078 String name = messageExchange.getIn().getHeader("org.apache.camel.MethodName", String.class);
079 if (name != null) {
080 methodInfo = operations.get(name);
081 }
082 if (methodInfo == null) {
083 methodInfo = defaultExpression;
084 }
085 if (methodInfo != null) {
086 return methodInfo.createMethodInvocation(pojo, messageExchange);
087 }
088 return null;
089 }
090
091 protected void introspect(Class clazz) {
092 Method[] methods = clazz.getDeclaredMethods();
093 for (Method method : methods) {
094 introspect(clazz, method);
095 }
096 Class superclass = clazz.getSuperclass();
097 if (superclass != null && !superclass.equals(Object.class)) {
098 introspect(superclass);
099 }
100 }
101
102 protected MethodInfo introspect(Class clazz, Method method) {
103 Class[] parameterTypes = method.getParameterTypes();
104 Annotation[][] parameterAnnotations = method.getParameterAnnotations();
105 final Expression[] parameterExpressions = new Expression[parameterTypes.length];
106 for (int i = 0; i < parameterTypes.length; i++) {
107 Class parameterType = parameterTypes[i];
108 Expression expression = createParameterUnmarshalExpression(clazz, method,
109 parameterType, parameterAnnotations[i]);
110 if (expression == null) {
111 if (log.isDebugEnabled()) {
112 log.debug("No expression available for method: "
113 + method.toString() + " parameter: " + i + " so ignoring method");
114 }
115 if (parameterTypes.length == 1) {
116 // lets assume its the body
117 expression = ExpressionBuilder.bodyExpression(parameterType);
118 }
119 else {
120 return null;
121 }
122 }
123 parameterExpressions[i] = expression;
124 }
125
126 // now lets add the method to the repository
127 String opName = method.getName();
128
129 /*
130
131 TODO allow an annotation to expose the operation name to use
132
133 if (method.getAnnotation(Operation.class) != null) {
134 String name = method.getAnnotation(Operation.class).name();
135 if (name != null && name.length() > 0) {
136 opName = name;
137 }
138 }
139 */
140 Expression parametersExpression = createMethodParametersExpression(parameterExpressions);
141 MethodInfo methodInfo = new MethodInfo(clazz, method, parametersExpression);
142 operations.put(opName, methodInfo);
143 return methodInfo;
144 }
145
146 protected Expression createMethodParametersExpression(final Expression[] parameterExpressions) {
147 return new Expression<Exchange>() {
148 public Object evaluate(Exchange exchange) {
149 Object[] answer = new Object[parameterExpressions.length];
150 for (int i = 0; i < parameterExpressions.length; i++) {
151 Expression parameterExpression = parameterExpressions[i];
152 answer[i] = parameterExpression.evaluate(exchange);
153 }
154 return answer;
155 }
156
157 @Override
158 public String toString() {
159 return "parametersExpression" + Arrays.asList(parameterExpressions);
160 }
161 };
162 }
163
164 /**
165 * Creates an expression for the given parameter type if the parameter can be mapped
166 * automatically or null if the parameter cannot be mapped due to unsufficient
167 * annotations or not fitting with the default type conventions.
168 */
169 protected Expression createParameterUnmarshalExpression(Class clazz, Method method, Class parameterType, Annotation[] parameterAnnotation) {
170
171 // TODO look for a parameter annotation that converts into an expression
172 for (Annotation annotation : parameterAnnotation) {
173 Expression answer = createParameterUnmarshalExpressionForAnnotation(
174 clazz, method, parameterType, annotation);
175 if (answer != null) {
176 return answer;
177 }
178 }
179 return strategy.getDefaultParameterTypeExpression(parameterType);
180 }
181
182 protected Expression createParameterUnmarshalExpressionForAnnotation(Class clazz, Method method, Class parameterType, Annotation annotation) {
183 if (annotation instanceof Property) {
184 Property propertyAnnotation = (Property) annotation;
185 return ExpressionBuilder.propertyExpression(propertyAnnotation.name());
186 }
187 else if (annotation instanceof Header) {
188 Header headerAnnotation = (Header) annotation;
189 return ExpressionBuilder.headerExpression(headerAnnotation.name());
190 }
191 else if (annotation instanceof Body) {
192 Body content = (Body) annotation;
193 return ExpressionBuilder.bodyExpression(parameterType);
194
195 // TODO allow annotations to be used to create expressions?
196 /*
197 } else if (annotation instanceof XPath) {
198 XPath xpathAnnotation = (XPath) annotation;
199 return new JAXPStringXPathExpression(xpathAnnotation.xpath());
200 }
201 */
202 }
203 return null;
204 }
205 }