001    /*
002      GRANITE DATA SERVICES
003      Copyright (C) 2011 GRANITE DATA SERVICES S.A.S.
004    
005      This file is part of Granite Data Services.
006    
007      Granite Data Services is free software; you can redistribute it and/or modify
008      it under the terms of the GNU Library General Public License as published by
009      the Free Software Foundation; either version 2 of the License, or (at your
010      option) any later version.
011    
012      Granite Data Services is distributed in the hope that it will be useful, but
013      WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
014      FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License
015      for more details.
016    
017      You should have received a copy of the GNU Library General Public License
018      along with this library; if not, see <http://www.gnu.org/licenses/>.
019    */
020    
021    package org.granite.messaging.amf.io.util.externalizer;
022    
023    import java.io.IOException;
024    import java.io.ObjectInput;
025    import java.io.ObjectOutput;
026    import java.util.LinkedHashMap;
027    import java.util.Map;
028    import java.util.Map.Entry;
029    
030    /**
031     * @author Igor SAZHNEV
032     */
033    public class MapExternalizer extends DefaultExternalizer {
034    
035        @Override
036        public int accept(Class<?> clazz) {
037            return Map.class.isAssignableFrom(clazz) ? 1 : -1;
038        }
039    
040        @Override
041        public void readExternal(Object o, ObjectInput in) throws IOException, ClassNotFoundException, IllegalAccessException {
042            @SuppressWarnings("unchecked")
043                    Map<Object, Object> map = (Map<Object, Object>)o;
044            int size = in.readInt();
045            for (int i = 0; i < size; i++) {
046                    Object key = in.readObject();
047                    Object value = in.readObject();
048                    map.put(key, value);
049            }
050        }
051    
052        @Override
053        public void writeExternal(Object o, ObjectOutput out) throws IOException, IllegalAccessException {
054            // Copy the map to limit the possibility of concurrent modification exceptions
055            // use a LinkedHashMap to keep order of elements
056            @SuppressWarnings("unchecked")
057                    Map<Object, Object> map = new LinkedHashMap<Object, Object>((Map<Object, Object>)o);
058            out.writeInt(map.size());
059            for (Entry<Object, Object> entry : map.entrySet()) {
060                    out.writeObject(entry.getKey());
061                    out.writeObject(entry.getValue());
062            }
063        }
064    }