    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
    018    package org.apache.commons.configuration;
    019
    020    import java.util.AbstractMap;
    021    import java.util.AbstractSet;
    022    import java.util.Iterator;
    023    import java.util.Map;
    024    import java.util.Set;
    025
    026    /**
    027     * <p>The {@code ConfigurationMap} wraps a
    028     * configuration-collection
    029     * {@link org.apache.commons.configuration.Configuration}
    030     * instance to provide a {@code Map} interface.</p>
    031     *
    032     * <p><em>Note:</em> This implementation is incomplete.</p>
    033     *
    034     * @author <a href="mailto:ricardo.gladwell@btinternet.com">Ricardo Gladwell</a>
    035     * @version $Id: ConfigurationMap.java 1208794 2011-11-30 21:17:44Z oheger $
    036     * @since 1.0
    037     */
    038    public class ConfigurationMap extends AbstractMap<Object, Object>
    039    {
    040        /**
    041         * The {@code Configuration} wrapped by this class.
    042         */
    043        private Configuration configuration;
    044
    045        /**
    046         * Creates a new instance of a {@code ConfigurationMap}
    047         * that wraps the specified {@code Configuration}
    048         * instance.
    049         * @param configuration {@code Configuration}
    050         * instance.
    051         */
    052        public ConfigurationMap(Configuration configuration)
    053        {
    054            this.configuration = configuration;
    055        }
    056
    057        /**
    058         * Returns the wrapped {@code Configuration} object.
    059         *
    060         * @return the wrapped configuration
    061         * @since 1.2
    062         */
    063        public Configuration getConfiguration()
    064        {
    065            return configuration;
    066        }
    067
    068        /**
    069         * Returns a set with the entries contained in this configuration-based map.
    070         *
    071         * @return a set with the contained entries
    072         * @see java.util.Map#entrySet()
    073         */
    074        @Override
    075        public Set<Map.Entry<Object, Object>> entrySet()
    076        {
    077            return new ConfigurationSet(configuration);
    078        }
    079
    080        /**
    081         * Stores the value for the specified key. The value is stored in the
    082         * underlying configuration.
    083         *
    084         * @param key the key (will be converted to a string)
    085         * @param value the value
    086         * @return the old value of this key or <b>null</b> if it is new
    087         * @see java.util.Map#put(java.lang.Object, java.lang.Object)
    088         */
    089        @Override
    090        public Object put(Object key, Object value)
    091        {
    092            String strKey = String.valueOf(key);
    093            Object old = configuration.getProperty(strKey);
    094            configuration.setProperty(strKey, value);
    095            return old;
    096        }
    097
    098        /**
    099         * Returns the value of the specified key. The key is converted to a string
    100         * and then passed to the underlying configuration.
    101         *
    102         * @param key the key
    103         * @return the value of this key
    104         * @see java.util.Map#get(java.lang.Object)
    105         */
    106        @Override
    107        public Object get(Object key)
    108        {
    109            return configuration.getProperty(String.valueOf(key));
    110        }
    111
    112        /**
    113         * Set of entries in the map.
    114         */
    115        static class ConfigurationSet extends AbstractSet<Map.Entry<Object, Object>>
    116        {
    117            /** The configuration mapped to this entry set. */
    118            private Configuration configuration;
    119
    120            /**
    121             * A Map entry in the ConfigurationMap.
    122             */
    123            private final class Entry implements Map.Entry<Object, Object>
    124            {
    125                /** The key of the map entry. */
    126                private Object key;
    127
    128                private Entry(Object key)
    129                {
    130                    this.key = key;
    131                }
    132
    133                public Object getKey()
    134                {
    135                    return key;
    136                }
    137
    138                public Object getValue()
    139                {
    140                    return configuration.getProperty((String) key);
    141                }
    142
    143                public Object setValue(Object value)
    144                {
    145                    Object old = getValue();
    146                    configuration.setProperty((String) key, value);
    147                    return old;
    148                }
    149            }
    150
    151            /**
    152             * Iterator over the entries in the ConfigurationMap.
    153             */
    154            private final class ConfigurationSetIterator implements Iterator<Map.Entry<Object, Object>>
    155            {
    156                /** An iterator over the keys in the configuration. */
    157                private Iterator<String> keys;
    158
    159                private ConfigurationSetIterator()
    160                {
    161                    keys = configuration.getKeys();
    162                }
    163
    164                public boolean hasNext()
    165                {
    166                    return keys.hasNext();
    167                }
    168
    169                public Map.Entry<Object, Object> next()
    170                {
    171                    return new Entry(keys.next());
    172                }
    173
    174                public void remove()
    175                {
    176                    keys.remove();
    177                }
    178            }
    179
    180            ConfigurationSet(Configuration configuration)
    181            {
    182                this.configuration = configuration;
    183            }
    184
    185            /**
    186             * @see java.util.Collection#size()
    187             */
    188            @Override
    189            public int size()
    190            {
    191                // Ouch. Now _that_ one is expensive...
    192                int count = 0;
    193                for (Iterator<String> iterator = configuration.getKeys(); iterator.hasNext();)
    194                {
    195                    iterator.next();
    196                    count++;
    197                }
    198                return count;
    199            }
    200
    201            /**
    202             * @see java.util.Collection#iterator()
    203             */
    204            @Override
    205            public Iterator<Map.Entry<Object, Object>> iterator()
    206            {
    207                return new ConfigurationSetIterator();
    208            }
    209        }
    210    }