001    /**
002     *   GRANITE DATA SERVICES
003     *   Copyright (C) 2006-2013 GRANITE DATA SERVICES S.A.S.
004     *
005     *   This file is part of the Granite Data Services Platform.
006     *
007     *   Granite Data Services is free software; you can redistribute it and/or
008     *   modify it under the terms of the GNU Lesser General Public
009     *   License as published by the Free Software Foundation; either
010     *   version 2.1 of the License, or (at your option) any later version.
011     *
012     *   Granite Data Services is distributed in the hope that it will be useful,
013     *   but WITHOUT ANY WARRANTY; without even the implied warranty of
014     *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
015     *   General Public License for more details.
016     *
017     *   You should have received a copy of the GNU Lesser General Public
018     *   License along with this library; if not, write to the Free Software
019     *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
020     *   USA, or see <http://www.gnu.org/licenses/>.
021     */
022    package org.granite.util;
023    
024    import java.lang.reflect.ParameterizedType;
025    import java.lang.reflect.Type;
026    import java.lang.reflect.WildcardType;
027    import java.util.HashMap;
028    import java.util.Map;
029    import java.util.SortedMap;
030    import java.util.TreeMap;
031    
032    /**
033     * @author Franck WOLFF
034     */
035    public class MapUtil {
036    
037        public static Type[] getComponentTypes(Type mapType) {
038            final Class<?> mapClass = TypeUtil.classOfType(mapType);
039    
040            if (!Map.class.isAssignableFrom(mapClass))
041                return null;
042    
043            Type[] componentTypes = new Type[] {
044                WildcardType.class,
045                WildcardType.class
046            };
047    
048            if (mapType instanceof ParameterizedType) {
049                Type[] argTypes = ((ParameterizedType)mapType).getActualTypeArguments();
050                if (argTypes != null) {
051                    if (argTypes.length > 0)
052                        componentTypes[0] = argTypes[0];
053                    if (argTypes.length > 1)
054                        componentTypes[1] = argTypes[1];
055                }
056            }
057    
058            return componentTypes;
059        }
060    
061        @SuppressWarnings("unchecked")
062        public static Map<Object, Object> newMap(Class<?> targetClass, int length)
063            throws InstantiationException, IllegalAccessException  {
064    
065            if (targetClass.isInterface()) {
066    
067                if (SortedMap.class.isAssignableFrom(targetClass))
068                    return new TreeMap<Object, Object>();
069    
070                if (targetClass.isAssignableFrom(HashMap.class))
071                    return new HashMap<Object, Object>(length);
072    
073                throw new IllegalArgumentException("Unsupported collection interface: " + targetClass);
074            }
075    
076            return (Map<Object, Object>)targetClass.newInstance();
077        }
078    }