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.camel.converter;
018    
019    import java.util.ArrayList;
020    import java.util.Arrays;
021    import java.util.Collection;
022    import java.util.HashMap;
023    import java.util.HashSet;
024    import java.util.Hashtable;
025    import java.util.Iterator;
026    import java.util.LinkedList;
027    import java.util.List;
028    import java.util.Map;
029    import java.util.Properties;
030    import java.util.Set;
031    
032    import org.apache.camel.Converter;
033    
034    /**
035     * Some core java.util Collection based
036     * <a href="http://activemq.apache.org/camel/type-converter.html">Type Converters</a>
037     *
038     * @version $Revision: 1206 $
039     */
040    @Converter
041    public final class CollectionConverter {
042    
043        /**
044         * Utility classes should not have a public constructor.
045         */
046        private CollectionConverter() {
047        }
048    
049        /**
050         * Converts a collection to an array
051         */
052        @Converter
053        public static Object[] toArray(Collection value) {
054            if (value == null) {
055                return null;
056            }
057            return value.toArray();
058        }
059    
060        /**
061         * Converts an array to a collection
062         */
063        @Converter
064        public static List toList(Object[] array) {
065            return Arrays.asList(array);
066        }
067    
068        /**
069         * Converts a collection to a List if it is not already
070         */
071        @Converter
072        public static List toList(Collection collection) {
073            return new ArrayList(collection);
074        }
075        
076        /**
077         * Converts an {@link Iterator} to a {@link ArrayList}
078         */
079        @Converter
080        public static ArrayList toArrayList(Iterator it) {
081            ArrayList list = new ArrayList();
082            while (it.hasNext()) {
083                list.add(it.next());
084            }
085            return list;
086        }
087    
088        @Converter
089        public static Set toSet(Object[] array) {
090            Set answer = new HashSet();
091            answer.addAll(Arrays.asList(array));
092            return answer;
093        }
094    
095        @Converter
096        public static Set toSet(Collection collection) {
097            return new HashSet(collection);
098        }
099    
100        @Converter
101        public static Set toSet(Map map) {
102            return map.entrySet();
103        }
104    
105        @Converter
106        public static Properties toProperties(Map map) {
107            Properties answer = new Properties();
108            answer.putAll(map);
109            return answer;
110        }
111    
112        @Converter
113        public static Hashtable toHashtable(Map map) {
114            return new Hashtable(map);
115        }
116    
117        @Converter
118        public static HashMap toHashMap(Map map) {
119            return new HashMap(map);
120        }
121    
122        /**
123         * Converts an {@link Iterable} into a {@link List} 
124         */
125        @Converter
126        public static List toList(Iterable iterable) {
127            if (iterable instanceof List) {
128                return (List) iterable;
129            }
130            List result = new LinkedList();
131            for (Object value : iterable) {
132                result.add(value);
133            }
134            return result;
135        }
136    }