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 */ 017package org.apache.camel.component.bean; 018 019import java.lang.annotation.Annotation; 020import java.lang.reflect.Method; 021 022import org.apache.camel.CamelContext; 023import org.apache.camel.Expression; 024import org.apache.camel.Predicate; 025import org.apache.camel.language.LanguageAnnotation; 026import org.apache.camel.spi.Language; 027import org.apache.camel.util.ObjectHelper; 028import org.apache.camel.util.PredicateToExpressionAdapter; 029 030/** 031 * Default implementation of the {@link AnnotationExpressionFactory}. 032 * 033 * @version 034 */ 035public class DefaultAnnotationExpressionFactory implements AnnotationExpressionFactory { 036 037 public Expression createExpression(CamelContext camelContext, Annotation annotation, LanguageAnnotation languageAnnotation, Class<?> expressionReturnType) { 038 String languageName = languageAnnotation.language(); 039 if (languageName == null) { 040 throw new IllegalArgumentException("Cannot determine the language from the annotation: " + annotation); 041 } 042 Language language = camelContext.resolveLanguage(languageName); 043 if (language == null) { 044 throw new IllegalArgumentException("Cannot find the language: " + languageName + " on the classpath"); 045 } 046 String expression = getExpressionFromAnnotation(annotation); 047 048 if (expressionReturnType == Boolean.class || expressionReturnType == boolean.class) { 049 Predicate predicate = language.createPredicate(expression); 050 return PredicateToExpressionAdapter.toExpression(predicate); 051 } else { 052 return language.createExpression(expression); 053 } 054 } 055 056 protected String getExpressionFromAnnotation(Annotation annotation) { 057 Object value = getAnnotationObjectValue(annotation, "value"); 058 if (value == null) { 059 throw new IllegalArgumentException("Cannot determine the expression from the annotation: " + annotation); 060 } 061 return value.toString(); 062 } 063 064 /** 065 * @param annotation The annotation to get the value of 066 * @param methodName The annotation name 067 * @return The value of the annotation 068 */ 069 protected Object getAnnotationObjectValue(Annotation annotation, String methodName) { 070 try { 071 Method method = annotation.getClass().getMethod(methodName); 072 Object value = ObjectHelper.invokeMethod(method, annotation); 073 return value; 074 } catch (NoSuchMethodException e) { 075 throw new IllegalArgumentException("Cannot determine the Object value of the annotation: " + annotation 076 + " as it does not have the method: " + methodName + "() method", e); 077 } 078 } 079}