de.javakaffee.kryoserializers.guava.ImmutableMapSerializer Maven / Gradle / Ivy

Go to download
package de.javakaffee.kryoserializers.guava;

import com.esotericsoftware.kryo.Kryo;
import com.esotericsoftware.kryo.Serializer;
import com.esotericsoftware.kryo.io.Input;
import com.esotericsoftware.kryo.io.Output;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableTable;
import com.google.common.collect.Maps;

import java.util.EnumMap;
import java.util.HashMap;
import java.util.Map;


/**
 * A kryo {@link Serializer} for guava-libraries {@link ImmutableMap}.
 */
public class ImmutableMapSerializer extends Serializer> {

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

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

    @Override
    public void write(Kryo kryo, Output output, ImmutableMap immutableMap) {
        kryo.writeObject(output, Maps.newHashMap(immutableMap));
    }

    @Override
    public ImmutableMap read(Kryo kryo, Input input, Class> type) {
        Map map = kryo.readObject(input, HashMap.class);
        return ImmutableMap.copyOf(map);
    }

    /**
     * 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) {

        // we're writing a HashMap, therefore we should register it
        kryo.register(java.util.HashMap.class);

        final ImmutableMapSerializer serializer = new ImmutableMapSerializer();

        // ImmutableMap (abstract class)
        //  +- EmptyImmutableBiMap
        //  +- SingletonImmutableBiMap
        //  +- RegularImmutableMap
        //  +- ImmutableEnumMap
        //  +- RowMap from DenseImmutableTable
        //  +- Row from DenseImmutableTable
        //  +- ColumnMap from DenseImmutableTable
        //  +- Column from DenseImmutableTable

        kryo.register(ImmutableMap.class, serializer);
        kryo.register(ImmutableMap.of().getClass(), serializer);

        Object o1 = new Object();
        Object o2 = new Object();

        kryo.register(ImmutableMap.of(o1, o1).getClass(), serializer);
        kryo.register(ImmutableMap.of(o1, o1, o2, o2).getClass(), serializer);

        Map enumMap = new EnumMap(DummyEnum.class);
        for (DummyEnum e : DummyEnum.values()) {
            enumMap.put(e, o1);
        }

        kryo.register(ImmutableMap.copyOf(enumMap).getClass(), serializer);

        ImmutableTable denseImmutableTable = ImmutableTable.builder()
                .put("a", 1, 1)
                .put("b", 1, 1)
                .build();

        kryo.register(denseImmutableTable.rowMap().getClass(), serializer); // RowMap
        kryo.register(denseImmutableTable.rowMap().get("a").getClass(), serializer); // Row
        kryo.register(denseImmutableTable.columnMap().getClass(), serializer); // ColumnMap
        kryo.register(denseImmutableTable.columnMap().get(1).getClass(), serializer); // Column
    }

    private enum DummyEnum {
        VALUE1,
        VALUE2
    }
}