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.discovery.resource.names;
018    
019    import java.util.Dictionary;
020    import java.util.Hashtable;
021    
022    import org.apache.commons.discovery.ResourceNameDiscover;
023    import org.apache.commons.discovery.ResourceNameIterator;
024    import org.apache.commons.logging.Log;
025    import org.apache.commons.logging.LogFactory;
026    
027    /**
028     * Recover resources from a Dictionary.  This covers Properties as well,
029     * since <code>Properties extends Hashtable extends Dictionary</code>.
030     *
031     * The recovered value is expected to be either a <code>String</code>
032     * or a <code>String[]</code>.
033     */
034    public class DiscoverNamesInDictionary extends ResourceNameDiscoverImpl implements ResourceNameDiscover {
035    
036        private static Log log = LogFactory.getLog(DiscoverNamesInDictionary.class);
037    
038        /**
039         * Sets the {@code Log} for this class.
040         *
041         * @param _log This class {@code Log}
042         * @deprecated This method is not thread-safe
043         */
044        @Deprecated
045        public static void setLog(Log _log) {
046            log = _log;
047        }
048    
049        private Dictionary<String, String[]> dictionary;
050    
051        /**
052         * Construct a new resource discoverer with an empty Dictionary.
053         */
054        public DiscoverNamesInDictionary() {
055            setDictionary(new Hashtable<String, String[]>());
056        }
057    
058        /**
059         * Construct a new resource discoverer with the given Dictionary.
060         *
061         * @param dictionary The initial Dictionary
062         */
063        public DiscoverNamesInDictionary(Dictionary<String, String[]> dictionary) {
064            setDictionary(dictionary);
065        }
066    
067        /**
068         * Returns the current Dictionary for names mapping.
069         *
070         * @return The current Dictionary for names mapping
071         */
072        protected Dictionary<String, String[]> getDictionary() {
073            return dictionary;
074        }
075    
076        /**
077         * Specify the Dictionary for names mapping.
078         *
079         * @param table The Dictionary for names mapping
080         */
081        public void setDictionary(Dictionary<String, String[]> table) {
082            this.dictionary = table;
083        }
084    
085        /**
086         * Add a resource name to a single name mapping.
087         *
088         * @param resourceName The resource name
089         * @param resource The target name
090         */
091        public void addResource(String resourceName, String resource) {
092            addResource(resourceName, new String[]{ resource });
093        }
094    
095        /**
096         * Add a resource name to multiple names mapping.
097         *
098         * @param resourceName The resource name
099         * @param resources The target names
100         */
101        public void addResource(String resourceName, String[] resources) {
102            dictionary.put(resourceName, resources);
103        }
104    
105        /**
106         * {@inheritDoc}
107         */
108        @Override
109        public ResourceNameIterator findResourceNames(final String resourceName) {
110            if (log.isDebugEnabled()) {
111                log.debug("find: resourceName='" + resourceName + "'");
112            }
113    
114            final String[] resources = dictionary.get(resourceName);
115    
116            return new ResourceNameIterator() {
117                private int idx = 0;
118    
119                public boolean hasNext() {
120                    if (resources != null) {
121                        while (idx < resources.length  &&  resources[idx] == null) {
122                            idx++;
123                        }
124                        return idx < resources.length;
125                    }
126                    return false;
127                }
128    
129                public String nextResourceName() {
130                    return hasNext() ? resources[idx++] : null;
131                }
132            };
133        }
134    
135    }