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.language.XPath;
028    import org.apache.camel.util.ObjectHelper;
029    
030    /**
031     * Factory for the XPath expression annotations.
032     *
033     * @version $Revision: 773781 $
034     */
035    public class XPathAnnotationExpressionFactory extends DefaultAnnotationExpressionFactory {
036    
037        @Override
038        public Expression createExpression(CamelContext camelContext, Annotation annotation, LanguageAnnotation languageAnnotation, Class expressionReturnType) {
039            String xpath = getExpressionFromAnnotation(annotation);
040            XPathBuilder builder = XPathBuilder.xpath(xpath);
041            NamespacePrefix[] namespaces = getExpressionNameSpacePrefix(annotation);
042            if (namespaces != null) {
043                for (NamespacePrefix namespacePrefix : namespaces) {
044                    builder = builder.namespace(namespacePrefix.prefix(), namespacePrefix.uri());
045                }
046    
047            }
048            return builder;
049        }
050        
051        protected NamespacePrefix[] getExpressionNameSpacePrefix(Annotation annotation) {
052            try {
053                Method method = annotation.getClass().getMethod("namespaces");
054                Object value = ObjectHelper.invokeMethod(method, annotation);
055                return (NamespacePrefix[])value;
056            } catch (NoSuchMethodException e) {
057                throw new IllegalArgumentException("Cannot determine the annotation: " + annotation + " as it does not have an namespaces() method");
058            }        
059        }
060    }