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;
020
021import org.apache.camel.CamelContext;
022import org.apache.camel.Expression;
023import org.apache.camel.builder.xml.XPathBuilder;
024import org.apache.camel.language.LanguageAnnotation;
025import org.apache.camel.language.NamespacePrefix;
026import org.apache.camel.util.ObjectHelper;
027
028/**
029 * Factory for the XPath expression annotations.
030 *
031 * @version 
032 */
033public class XPathAnnotationExpressionFactory extends DefaultAnnotationExpressionFactory {
034
035    @Override
036    public Expression createExpression(CamelContext camelContext, Annotation annotation, LanguageAnnotation languageAnnotation, Class<?> expressionReturnType) {
037        String xpath = getExpressionFromAnnotation(annotation);
038        
039        Class<?> resultType = getResultType(annotation);
040        if (resultType.equals(Object.class)) {
041            resultType = expressionReturnType;
042        }
043        
044        XPathBuilder builder = XPathBuilder.xpath(xpath, resultType);        
045        NamespacePrefix[] namespaces = getExpressionNameSpacePrefix(annotation);
046        if (namespaces != null) {
047            for (NamespacePrefix namespacePrefix : namespaces) {
048                builder = builder.namespace(namespacePrefix.prefix(), namespacePrefix.uri());
049            }
050        }
051
052        // Set the header name that we want the XPathBuilder to apply the XPath expression to
053        String headerName = getHeaderName(annotation);
054        if (ObjectHelper.isNotEmpty(headerName)) {
055            builder.setHeaderName(headerName);
056        }
057        
058        return builder;
059    }
060
061    protected Class<?> getResultType(Annotation annotation) {
062        return (Class<?>) getAnnotationObjectValue(annotation, "resultType");
063    }
064    
065    protected NamespacePrefix[] getExpressionNameSpacePrefix(Annotation annotation) {
066        return (NamespacePrefix[]) getAnnotationObjectValue(annotation, "namespaces");
067    }
068    
069    /**
070     * Extracts the value of the header method in the Annotation. For backwards
071     * compatibility this method will return null if the annotation's method is
072     * not found.
073     * 
074     * @return If the annotation has the method 'header' then the name of the
075     *         header we want to apply the XPath expression to. Otherwise null
076     *         will be returned
077     */
078    protected String getHeaderName(Annotation annotation) {
079        String headerValue = null;
080        try {
081            headerValue = (String)getAnnotationObjectValue(annotation, "headerName");
082        } catch (Exception e) {
083            // Do Nothing
084        }
085        return headerValue;
086    }
087}