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.builder.xml.XPathBuilder;
025    import org.apache.camel.language.LanguageAnnotation;
026    import org.apache.camel.language.NamespacePrefix;
027    import org.apache.camel.util.ObjectHelper;
028    
029    /**
030     * Factory for the XPath expression annotations.
031     *
032     * @version 
033     */
034    public class XPathAnnotationExpressionFactory extends DefaultAnnotationExpressionFactory {
035    
036        @Override
037        public Expression createExpression(CamelContext camelContext, Annotation annotation, LanguageAnnotation languageAnnotation, Class<?> expressionReturnType) {
038            String xpath = getExpressionFromAnnotation(annotation);
039            
040            Class<?> resultType = getResultType(annotation);
041            if (resultType.equals(Object.class)) {
042                resultType = expressionReturnType;
043            }
044            
045            XPathBuilder builder = XPathBuilder.xpath(xpath, resultType);        
046            NamespacePrefix[] namespaces = getExpressionNameSpacePrefix(annotation);
047            if (namespaces != null) {
048                for (NamespacePrefix namespacePrefix : namespaces) {
049                    builder = builder.namespace(namespacePrefix.prefix(), namespacePrefix.uri());
050                }
051    
052            }
053            return builder;
054        }
055    
056        protected Class<?> getResultType(Annotation annotation) {
057            try {
058                Method method = annotation.getClass().getMethod("resultType");
059                Object value = ObjectHelper.invokeMethod(method, annotation);
060                return (Class<?>) value;
061            } catch (NoSuchMethodException e) {
062                throw new IllegalArgumentException("Cannot determine the annotation: " + annotation + " as it does not have an resultType() method", e);
063            }
064        }
065    
066        protected NamespacePrefix[] getExpressionNameSpacePrefix(Annotation annotation) {
067            try {
068                Method method = annotation.getClass().getMethod("namespaces");
069                Object value = ObjectHelper.invokeMethod(method, annotation);
070                return (NamespacePrefix[]) value;
071            } catch (NoSuchMethodException e) {
072                throw new IllegalArgumentException("Cannot determine the annotation: " + annotation + " as it does not have an namespaces() method", e);
073            }
074        }
075    }