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.commons.jxpath.util;
018    
019    import org.apache.commons.jxpath.BasicNodeSet;
020    import org.apache.commons.jxpath.ExtendedKeyManager;
021    import org.apache.commons.jxpath.JXPathContext;
022    import org.apache.commons.jxpath.KeyManager;
023    import org.apache.commons.jxpath.NodeSet;
024    import org.apache.commons.jxpath.Pointer;
025    import org.apache.commons.jxpath.ri.InfoSetUtil;
026    
027    /**
028     * Utility class.
029     *
030     * @author Matt Benson
031     * @since JXPath 1.3
032     * @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
033     */
034    public class KeyManagerUtils {
035        /**
036         * Adapt KeyManager to implement ExtendedKeyManager.
037         */
038        private static class SingleNodeExtendedKeyManager implements
039                ExtendedKeyManager {
040            private KeyManager delegate;
041    
042            /**
043             * Create a new SingleNodeExtendedKeyManager.
044             * @param delegate KeyManager to wrap
045             */
046            public SingleNodeExtendedKeyManager(KeyManager delegate) {
047                this.delegate = delegate;
048            }
049    
050            public NodeSet getNodeSetByKey(JXPathContext context, String key,
051                    Object value) {
052                Pointer pointer = delegate.getPointerByKey(context, key, InfoSetUtil.stringValue(value));
053                BasicNodeSet result = new BasicNodeSet();
054                result.add(pointer);
055                return result;
056            }
057    
058            public Pointer getPointerByKey(JXPathContext context, String keyName,
059                    String keyValue) {
060                return delegate.getPointerByKey(context, keyName, keyValue);
061            }
062        }
063    
064        /**
065         * Get an ExtendedKeyManager from the specified KeyManager.
066         * @param keyManager to adapt, if necessary
067         * @return <code>keyManager</code> if it implements ExtendedKeyManager
068         *         or a basic single-result ExtendedKeyManager that delegates to
069         *         <code>keyManager</code>.
070         */
071        public static ExtendedKeyManager getExtendedKeyManager(KeyManager keyManager) {
072            return keyManager instanceof ExtendedKeyManager ? (ExtendedKeyManager) keyManager
073                    : new SingleNodeExtendedKeyManager(keyManager);
074        }
075    }