/*
* Copyright 2010 Martin Grotzke
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package de.javakaffee.kryoserializers;
import static com.esotericsoftware.minlog.Log.TRACE;
import static com.esotericsoftware.minlog.Log.trace;
import java.lang.reflect.Field;
import java.util.EnumMap;
import java.util.Map;
import com.esotericsoftware.kryo.Kryo;
import com.esotericsoftware.kryo.Serializer;
import com.esotericsoftware.kryo.io.Input;
import com.esotericsoftware.kryo.io.Output;
/**
* A serializer for {@link EnumMap}s.
*
* @author <a href="mailto:martin.grotzke@javakaffee.de">Martin Grotzke</a>
*/
public class EnumMapSerializer extends Serializer<EnumMap<? extends Enum<?>, ?>> {
private static final Field TYPE_FIELD;
static {
try {
TYPE_FIELD = EnumMap.class.getDeclaredField( "keyType" );
TYPE_FIELD.setAccessible( true );
} catch ( final Exception e ) {
throw new RuntimeException( "The EnumMap class seems to have changed, could not access expected field.", e );
}
}
// Workaround reference reading, this should be removed sometimes. See also
// https://groups.google.com/d/msg/kryo-users/Eu5V4bxCfws/k-8UQ22y59AJ
private static final Object FAKE_REFERENCE = new Object();
@Override
@SuppressWarnings({ "unchecked", "rawtypes" })
public EnumMap<? extends Enum<?>, ?> copy (final Kryo kryo, final EnumMap<? extends Enum<?>, ?> original) {
return new EnumMap(original);
}
@SuppressWarnings( { "unchecked", "rawtypes" } )
private EnumMap<? extends Enum<?>, ?> create(final Kryo kryo, final Input input,
final Class<EnumMap<? extends Enum<?>, ?>> type) {
final Class<? extends Enum<?>> keyType = kryo.readClass( input ).getType();
return new EnumMap( keyType );
}
@Override
@SuppressWarnings({ "rawtypes", "unchecked" })
public EnumMap<? extends Enum<?>, ?> read(final Kryo kryo, final Input input,
final Class<EnumMap<? extends Enum<?>, ?>> type) {
kryo.reference(FAKE_REFERENCE);
final EnumMap<? extends Enum<?>, ?> result = create(kryo, input, type);
final Class<Enum<?>> keyType = getKeyType( result );
final Enum<?>[] enumConstants = keyType.getEnumConstants();
final EnumMap rawResult = result;
final int size = input.readInt(true);
for ( int i = 0; i < size; i++ ) {
final int ordinal = input.readInt(true);
final Enum<?> key = enumConstants[ordinal];
final Object value = kryo.readClassAndObject( input );
rawResult.put( key, value );
}
return result;
}
@Override
public void write(final Kryo kryo, final Output output, final EnumMap<? extends Enum<?>, ?> map) {
kryo.writeClass( output, getKeyType( map ) );
output.writeInt(map.size(), true);
for ( final Map.Entry<? extends Enum<?>,?> entry : map.entrySet() ) {
output.writeInt(entry.getKey().ordinal(), true);
kryo.writeClassAndObject(output, entry.getValue());
}
if ( TRACE ) trace( "kryo", "Wrote EnumMap: " + map );
}
@SuppressWarnings("unchecked")
private Class<Enum<?>> getKeyType( final EnumMap<?, ?> map ) {
try {
return (Class<Enum<?>>)TYPE_FIELD.get( map );
} catch ( final Exception e ) {
throw new RuntimeException( "Could not access keys field.", e );
}
}
}