MapSerializer.java

package de.javakaffee.kryoserializers.dexx;

import com.esotericsoftware.kryo.Kryo;
import com.esotericsoftware.kryo.Serializer;
import com.esotericsoftware.kryo.io.Input;
import com.esotericsoftware.kryo.io.Output;

import com.github.andrewoma.dexx.collection.Map;
import com.github.andrewoma.dexx.collection.Maps;
import com.github.andrewoma.dexx.collection.Pair;

import java.util.HashMap;
import java.util.ArrayList;
import java.util.Map.Entry;

/**
* A kryo {@link Serializer} for dexx {@link Map}
 */
public class MapSerializer extends Serializer<Map<Object, ? extends Object>> {

    private static final boolean DOES_NOT_ACCEPT_NULL = true;
    private static final boolean IMMUTABLE = true;

    public MapSerializer() {
        super(DOES_NOT_ACCEPT_NULL, IMMUTABLE);
    }

    @Override
    public void write(Kryo kryo, Output output, Map<Object, ? extends Object> immutableMap) {
        kryo.writeObject(output, immutableMap.asMap());
    }

    @Override
    public Map<Object, Object> read(Kryo kryo, Input input, Class<Map<Object, ? extends Object>> type) {
        HashMap<Object, Object> map = kryo.readObject(input, HashMap.class);
        ArrayList<Pair<Object, Object>> listOfPairs = new ArrayList();

        for (Entry<Object, Object> entry : map.entrySet()) {
            Pair pair = new Pair(entry.getKey(), entry.getValue());
            listOfPairs.add(pair);
        }

        return Maps.copyOf(listOfPairs);
    }

    /**
     * Creates a new {@link ImmutableMapSerializer} and registers its serializer
     * for the several ImmutableMap related classes.
     *
     * @param kryo the {@link Kryo} instance to set the serializer on
     */
     public static void registerSerializers(final Kryo kryo) {

         final MapSerializer serializer = new MapSerializer();

         kryo.register(Map.class, serializer);
         kryo.register(Maps.of().getClass(), serializer);

         Object o1 = new Object();
         Object o2 = new Object();
         Object o3 = new Object();
         Object o4 = new Object();
         Object o5 = new Object();

         kryo.register(Maps.of(o1, o1).getClass(), serializer);
         kryo.register(Maps.of(o1, o1, o2, o2).getClass(), serializer);
         kryo.register(Maps.of(o1, o1, o2, o2, o3, o3).getClass(), serializer);
         kryo.register(Maps.of(o1, o1, o2, o2, o3, o3, o4, o4).getClass(), serializer);
         kryo.register(Maps.of(o1, o1, o2, o2, o3, o3, o4, o4, o5, o5).getClass(), serializer);

     }
}