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.component.bean;
018    
019    import java.lang.annotation.Annotation;
020    import java.lang.reflect.AccessibleObject;
021    import java.lang.reflect.AnnotatedElement;
022    import java.lang.reflect.InvocationTargetException;
023    import java.lang.reflect.Method;
024    import java.util.ArrayList;
025    import java.util.Arrays;
026    import java.util.List;
027    
028    import org.apache.camel.Exchange;
029    import org.apache.camel.ExchangePattern;
030    import org.apache.camel.Expression;
031    import org.apache.camel.Pattern;
032    import org.apache.camel.impl.ExpressionAdapter;
033    import org.apache.camel.processor.RecipientList;
034    import org.apache.camel.util.ObjectHelper;
035    import org.apache.commons.logging.Log;
036    import org.apache.commons.logging.LogFactory;
037    
038    import static org.apache.camel.util.ObjectHelper.asString;
039    
040    /**
041     * Information about a method to be used for invocation.
042     *
043     * @version $Revision: 749201 $
044     */
045    public class MethodInfo {
046        private static final transient Log LOG = LogFactory.getLog(MethodInfo.class);
047    
048        private Class type;
049        private Method method;
050        private final List<ParameterInfo> parameters;
051        private final List<ParameterInfo> bodyParameters;
052        private final boolean hasCustomAnnotation;
053        private Expression parametersExpression;
054        private ExchangePattern pattern = ExchangePattern.InOut;
055        private RecipientList recipientList;
056    
057        public MethodInfo(Class type, Method method, List<ParameterInfo> parameters, List<ParameterInfo> bodyParameters, boolean hasCustomAnnotation) {
058            this.type = type;
059            this.method = method;
060            this.parameters = parameters;
061            this.bodyParameters = bodyParameters;
062            this.hasCustomAnnotation = hasCustomAnnotation;
063            this.parametersExpression = createParametersExpression();
064            Pattern oneway = findOneWayAnnotation(method);
065            if (oneway != null) {
066                pattern = oneway.value();
067            }
068            if (method.getAnnotation(org.apache.camel.RecipientList.class) != null) {
069                recipientList = new RecipientList();
070            }
071        }
072    
073        public String toString() {
074            return method.toString();
075        }
076    
077        public MethodInvocation createMethodInvocation(final Object pojo, final Exchange exchange) {
078            final Object[] arguments = (Object[]) parametersExpression.evaluate(exchange);
079            return new MethodInvocation() {
080                public Method getMethod() {
081                    return method;
082                }
083    
084                public Object[] getArguments() {
085                    return arguments;
086                }
087    
088                public Object proceed() throws Exception {
089                    if (LOG.isTraceEnabled()) {
090                        LOG.trace(">>>> invoking: " + method + " on bean: " + pojo + " with arguments: " + asString(arguments) + " for exchange: " + exchange);
091                    }
092                    Object result = invoke(method, pojo, arguments, exchange);
093                    if (recipientList != null) {
094                        recipientList.sendToRecipientList(exchange, result);
095                    }
096                    return result;
097                }
098    
099                public Object getThis() {
100                    return pojo;
101                }
102    
103                public AccessibleObject getStaticPart() {
104                    return method;
105                }
106            };
107        }
108    
109        public Class getType() {
110            return type;
111        }
112    
113        public Method getMethod() {
114            return method;
115        }
116    
117        /**
118         * Returns the {@link org.apache.camel.ExchangePattern} that should be used when invoking this method. This value
119         * defaults to {@link org.apache.camel.ExchangePattern#InOut} unless some {@link org.apache.camel.Pattern} annotation is used
120         * to override the message exchange pattern.
121         *
122         * @return the exchange pattern to use for invoking this method.
123         */
124        public ExchangePattern getPattern() {
125            return pattern;
126        }
127    
128        public Expression getParametersExpression() {
129            return parametersExpression;
130        }
131    
132        public List<ParameterInfo> getBodyParameters() {
133            return bodyParameters;
134        }
135    
136        public Class getBodyParameterType() {
137            ParameterInfo parameterInfo = bodyParameters.get(0);
138            return parameterInfo.getType();
139        }
140    
141        public boolean bodyParameterMatches(Class bodyType) {
142            Class actualType = getBodyParameterType();
143            return actualType != null && ObjectHelper.isAssignableFrom(bodyType, actualType);
144        }
145    
146        public List<ParameterInfo> getParameters() {
147            return parameters;
148        }
149    
150        public boolean hasBodyParameter() {
151            return !bodyParameters.isEmpty();
152        }
153    
154        public boolean isHasCustomAnnotation() {
155            return hasCustomAnnotation;
156        }
157    
158        public boolean isReturnTypeVoid() {
159            return method.getReturnType().getName().equals("void");
160        }
161    
162        protected Object invoke(Method mth, Object pojo, Object[] arguments, Exchange exchange) throws IllegalAccessException, InvocationTargetException {
163            return mth.invoke(pojo, arguments);
164        }
165    
166        protected Expression createParametersExpression() {
167            final int size = parameters.size();
168            final Expression[] expressions = new Expression[size];
169            for (int i = 0; i < size; i++) {
170                Expression parameterExpression = parameters.get(i).getExpression();
171                expressions[i] = parameterExpression;
172            }
173            return new ExpressionAdapter() {
174                @SuppressWarnings("unchecked")
175                public Object evaluate(Exchange exchange) {
176                    Object[] answer = new Object[size];
177                    Object body = exchange.getIn().getBody();
178                    boolean multiParameterArray = false;
179                    if (exchange.getIn().getHeader(Exchange.BEAN_MULTI_PARAMETER_ARRAY) != null) {
180                        multiParameterArray = exchange.getIn().getHeader(Exchange.BEAN_MULTI_PARAMETER_ARRAY, Boolean.class);
181                    }
182                    for (int i = 0; i < size; i++) {
183                        Object value = null;
184                        if (multiParameterArray) {
185                            value = ((Object[])body)[i];
186                        } else {
187                            value = expressions[i].evaluate(exchange, parameters.get(i).getType());
188                        }
189                        // now lets try to coerce the value to the required type
190                        answer[i] = value;
191                    }
192                    return answer;
193                }
194    
195                @Override
196                public String toString() {
197                    return "ParametersExpression: " + Arrays.asList(expressions);
198                }
199            };
200        }
201    
202        /**
203         * Finds the oneway annotation in priority order; look for method level annotations first, then the class level annotations,
204         * then super class annotations then interface annotations
205         *
206         * @param method the method on which to search
207         * @return the first matching annotation or none if it is not available
208         */
209        protected Pattern findOneWayAnnotation(Method method) {
210            Pattern answer = getPatternAnnotation(method);
211            if (answer == null) {
212                Class<?> type = method.getDeclaringClass();
213    
214                // lets create the search order of types to scan
215                List<Class<?>> typesToSearch = new ArrayList<Class<?>>();
216                addTypeAndSuperTypes(type, typesToSearch);
217                Class[] interfaces = type.getInterfaces();
218                for (Class anInterface : interfaces) {
219                    addTypeAndSuperTypes(anInterface, typesToSearch);
220                }
221    
222                // now lets scan for a type which the current declared class overloads
223                answer = findOneWayAnnotationOnMethod(typesToSearch, method);
224                if (answer == null) {
225                    answer = findOneWayAnnotation(typesToSearch);
226                }
227            }
228            return answer;
229        }
230    
231        /**
232         * Returns the pattern annotation on the given annotated element; either as a direct annotation or
233         * on an annotation which is also annotated
234         *
235         * @param annotatedElement the element to look for the annotation
236         * @return the first matching annotation or null if none could be found
237         */
238        protected Pattern getPatternAnnotation(AnnotatedElement annotatedElement) {
239            return getPatternAnnotation(annotatedElement, 2);
240        }
241    
242        /**
243         * Returns the pattern annotation on the given annotated element; either as a direct annotation or
244         * on an annotation which is also annotated
245         *
246         * @param annotatedElement the element to look for the annotation
247         * @param depth the current depth
248         * @return the first matching annotation or null if none could be found
249         */
250        protected Pattern getPatternAnnotation(AnnotatedElement annotatedElement, int depth) {
251            Pattern answer = annotatedElement.getAnnotation(Pattern.class);
252            int nextDepth = depth - 1;
253    
254            if (nextDepth > 0) {
255                // lets look at all the annotations to see if any of those are annotated
256                Annotation[] annotations = annotatedElement.getAnnotations();
257                for (Annotation annotation : annotations) {
258                    Class<? extends Annotation> annotationType = annotation.annotationType();
259                    if (annotation instanceof Pattern || annotationType.equals(annotatedElement)) {
260                        continue;
261                    } else {
262                        Pattern another = getPatternAnnotation(annotationType, nextDepth);
263                        if (pattern != null) {
264                            if (answer == null) {
265                                answer = another;
266                            } else {
267                                LOG.warn("Duplicate pattern annotation: " + another + " found on annotation: " + annotation + " which will be ignored");
268                            }
269                        }
270                    }
271                }
272            }
273            return answer;
274        }
275    
276        /**
277         * Adds the current class and all of its base classes (apart from {@link Object} to the given list
278         */
279        protected void addTypeAndSuperTypes(Class<?> type, List<Class<?>> result) {
280            for (Class<?> t = type; t != null && t != Object.class; t = t.getSuperclass()) {
281                result.add(t);
282            }
283        }
284    
285        /**
286         * Finds the first annotation on the base methods defined in the list of classes
287         */
288        protected Pattern findOneWayAnnotationOnMethod(List<Class<?>> classes, Method method) {
289            for (Class<?> type : classes) {
290                try {
291                    Method definedMethod = type.getMethod(method.getName(), method.getParameterTypes());
292                    Pattern answer = getPatternAnnotation(definedMethod);
293                    if (answer != null) {
294                        return answer;
295                    }
296                } catch (NoSuchMethodException e) {
297                    // ignore
298                }
299            }
300            return null;
301        }
302    
303    
304        /**
305         * Finds the first annotation on the given list of classes
306         */
307        protected Pattern findOneWayAnnotation(List<Class<?>> classes) {
308            for (Class<?> type : classes) {
309                Pattern answer = getPatternAnnotation(type);
310                if (answer != null) {
311                    return answer;
312                }
313            }
314            return null;
315        }
316    
317    
318    }