001    /**
002     *
003     * Licensed to the Apache Software Foundation (ASF) under one or more
004     * contributor license agreements.  See the NOTICE file distributed with
005     * this work for additional information regarding copyright ownership.
006     * The ASF licenses this file to You under the Apache License, Version 2.0
007     * (the "License"); you may not use this file except in compliance with
008     * the License.  You may obtain a copy of the License at
009     *
010     * http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    package org.apache.camel.builder.xpath;
019    
020    import javax.xml.namespace.NamespaceContext;
021    import javax.xml.xpath.XPathFactory;
022    import java.util.HashMap;
023    import java.util.HashSet;
024    import java.util.Iterator;
025    import java.util.Map;
026    import java.util.Set;
027    
028    /**
029     * An implementation of {@link NamespaceContext} which uses a simple Map where
030     * the keys are the prefixes and the values are the URIs
031     *
032     * @version $Revision: $
033     */
034    public class DefaultNamespaceContext implements NamespaceContext {
035    
036        private final Map map;
037        private final NamespaceContext parent;
038    
039        public DefaultNamespaceContext() {
040            this(XPathFactory.newInstance());
041        }
042    
043        public DefaultNamespaceContext(XPathFactory factory) {
044            this.parent = factory.newXPath().getNamespaceContext();
045            this.map = new HashMap();
046        }
047    
048        public DefaultNamespaceContext(NamespaceContext parent, Map map) {
049            this.parent = parent;
050            this.map = map;
051        }
052    
053        /**
054         * A helper method to make it easy to create newly populated instances
055         */
056        public DefaultNamespaceContext add(String prefix, String uri) {
057            map.put(prefix, uri);
058            return this;
059        }
060    
061        public String getNamespaceURI(String prefix) {
062            String answer = (String) map.get(prefix);
063            if (answer == null && parent != null) {
064                return parent.getNamespaceURI(prefix);
065            }
066            return answer;
067        }
068    
069        public String getPrefix(String namespaceURI) {
070            for (Iterator iter = map.entrySet().iterator(); iter.hasNext();) {
071                Map.Entry entry = (Map.Entry) iter.next();
072                if (namespaceURI.equals(entry.getValue())) {
073                    return (String) entry.getKey();
074                }
075            }
076            if (parent != null) {
077                return parent.getPrefix(namespaceURI);
078            }
079            return null;
080        }
081    
082        public Iterator getPrefixes(String namespaceURI) {
083            Set set = new HashSet();
084            for (Iterator iter = map.entrySet().iterator(); iter.hasNext();) {
085                Map.Entry entry = (Map.Entry) iter.next();
086                if (namespaceURI.equals(entry.getValue())) {
087                    set.add(entry.getKey());
088                }
089            }
090            if (parent != null) {
091                Iterator iter = parent.getPrefixes(namespaceURI);
092                while (iter.hasNext()) {
093                    set.add(iter.next());
094                }
095            }
096            return set.iterator();
097        }
098    }