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.Method; 021 022 import org.apache.camel.CamelContext; 023 import org.apache.camel.Expression; 024 import org.apache.camel.language.LanguageAnnotation; 025 import org.apache.camel.spi.Language; 026 import org.apache.camel.util.ObjectHelper; 027 028 /** 029 * Default implementation of the {@link AnnotationExpressionFactory}. 030 * 031 * @version 032 */ 033 public class DefaultAnnotationExpressionFactory implements AnnotationExpressionFactory { 034 035 public Expression createExpression(CamelContext camelContext, Annotation annotation, LanguageAnnotation languageAnnotation, Class<?> expressionReturnType) { 036 String languageName = languageAnnotation.language(); 037 if (languageName == null) { 038 throw new IllegalArgumentException("Cannot determine the language from the annotation: " + annotation); 039 } 040 Language language = camelContext.resolveLanguage(languageName); 041 if (language == null) { 042 throw new IllegalArgumentException("Cannot find the language: " + languageName + " on the classpath"); 043 } 044 String expression = getExpressionFromAnnotation(annotation); 045 return language.createExpression(expression); 046 } 047 048 protected String getExpressionFromAnnotation(Annotation annotation) { 049 // let's try the 'value()' method 050 try { 051 Method method = annotation.getClass().getMethod("value"); 052 Object value = ObjectHelper.invokeMethod(method, annotation); 053 if (value == null) { 054 throw new IllegalArgumentException("Cannot determine the expression from the annotation: " + annotation); 055 } 056 return value.toString(); 057 } catch (NoSuchMethodException e) { 058 throw new IllegalArgumentException("Cannot determine the expression of the annotation: " + annotation + " as it does not have a value() method"); 059 } 060 } 061 }