001    /**
002     * Copyright 2005-2012 The Kuali Foundation
003     *
004     * Licensed under the Educational Community License, Version 2.0 (the "License");
005     * you may not use this file except in compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     * http://www.opensource.org/licenses/ecl2.php
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS,
012     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     * See the License for the specific language governing permissions and
014     * limitations under the License.
015     */
016    package org.kuali.rice.ken.util;
017    
018    import java.util.ArrayList;
019    import java.util.Iterator;
020    import java.util.List;
021    
022    import javax.xml.namespace.NamespaceContext;
023    
024    /**
025     * XPath NamespaceContext implementation that delegates in sequence to a list of NamespaceContexts,
026     * returning the first match. 
027     * @author Kuali Rice Team (rice.collab@kuali.org)
028     */
029    public class CompoundNamespaceContext implements NamespaceContext {
030        private final List<NamespaceContext> contexts;
031    
032        /**
033         * Constructs a CompoundNamespaceContext.java.
034         * @param first
035         * @param second
036         */
037        public CompoundNamespaceContext(NamespaceContext first, NamespaceContext second) {
038            this.contexts = new ArrayList<NamespaceContext>(2);
039            this.contexts.add(first);
040            this.contexts.add(second);
041        }
042        
043        /**
044         * Constructs a CompoundNamespaceContext.java.
045         * @param contexts
046         */
047        public CompoundNamespaceContext(List<NamespaceContext> contexts) {
048            this.contexts = contexts;
049        }
050    
051        /**
052         * @see javax.xml.namespace.NamespaceContext#getNamespaceURI(java.lang.String)
053         */
054        public String getNamespaceURI(String prefix) {
055            if (prefix == null) {
056                throw new IllegalArgumentException("The prefix cannot be null.");
057            }
058            for (NamespaceContext nc: contexts) {
059                String uri = nc.getNamespaceURI(prefix);
060                if (uri != null) {
061                    return uri;
062                }
063            }
064            return null;
065        }
066    
067        /**
068         * @see javax.xml.namespace.NamespaceContext#getPrefix(java.lang.String)
069         */
070        public String getPrefix(String namespaceURI) {
071            if (namespaceURI == null) {
072                throw new IllegalArgumentException("The namespace uri cannot be null.");
073            }
074            for (NamespaceContext nc: contexts) {
075                String prefix = nc.getPrefix(namespaceURI);
076                if (prefix != null) {
077                    return prefix;
078                }
079            }
080            return null;
081        }
082    
083        /**
084         * @see javax.xml.namespace.NamespaceContext#getPrefixes(java.lang.String)
085         */
086        public Iterator getPrefixes(String namespaceURI) {
087            if (namespaceURI == null) {
088                throw new IllegalArgumentException("The namespace uri cannot be null.");
089            }
090            for (NamespaceContext nc: contexts) {
091                Iterator prefixes = nc.getPrefixes(namespaceURI);
092                if (prefixes != null) {
093                    return prefixes;
094                }
095            }
096            return null;
097        }
098    }