/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.flink.api.java.typeutils.runtime;

import org.apache.flink.annotation.Internal;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.api.common.typeutils.TypeSerializerFactory;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.util.InstantiationUtil;

@Internal
public final class RuntimeSerializerFactory<T> implements TypeSerializerFactory<T>, java.io.Serializable {

	private static final long serialVersionUID = 1L;
	

	private static final String CONFIG_KEY_SER = "SER_DATA";

	private static final String CONFIG_KEY_CLASS = "CLASS_DATA";

	
	private TypeSerializer<T> serializer;

	private boolean firstSerializer = true;

	private Class<T> clazz;

	// Because we read the class from the TaskConfig and instantiate ourselves
	public RuntimeSerializerFactory() {}

	public RuntimeSerializerFactory(TypeSerializer<T> serializer, Class<T> clazz) {
		if (serializer == null || clazz == null) {
			throw new NullPointerException();
		}

		this.clazz = clazz;
		this.serializer = serializer;
	}


	@Override
	public void writeParametersToConfig(Configuration config) {
		try {
			InstantiationUtil.writeObjectToConfig(clazz, config, CONFIG_KEY_CLASS);
			InstantiationUtil.writeObjectToConfig(serializer, config, CONFIG_KEY_SER);
		}
		catch (Exception e) {
			throw new RuntimeException("Could not serialize serializer into the configuration.", e);
		}
	}

	@SuppressWarnings("unchecked")
	@Override
	public void readParametersFromConfig(Configuration config, ClassLoader cl) throws ClassNotFoundException {
		if (config == null || cl == null) {
			throw new NullPointerException();
		}
		
		try {
			this.clazz = (Class<T>) InstantiationUtil.readObjectFromConfig(config, CONFIG_KEY_CLASS, cl);
			this.serializer = (TypeSerializer<T>)  InstantiationUtil.readObjectFromConfig(config, CONFIG_KEY_SER, cl);
			firstSerializer = true;
		}
		catch (ClassNotFoundException e) {
			throw e;
		}
		catch (Exception e) {
			throw new RuntimeException("Could not load deserializer from the configuration.", e);
		}
	}

	@Override
	public TypeSerializer<T> getSerializer() {
		if (this.serializer != null) {
			if (firstSerializer) {
				firstSerializer = false;
				return this.serializer;
			} else {
				return this.serializer.duplicate();
			}
		} else {
			throw new RuntimeException("SerializerFactory has not been initialized from configuration.");
		}
	}

	@Override
	public Class<T> getDataType() {
		return clazz;
	}
	
	// --------------------------------------------------------------------------------------------
	
	@Override
	public int hashCode() {
		return clazz.hashCode() ^ serializer.hashCode();
	}
	
	@Override
	public boolean equals(Object obj) {
		if (obj != null && obj instanceof RuntimeSerializerFactory) {
			RuntimeSerializerFactory<?> other = (RuntimeSerializerFactory<?>) obj;
			
			return this.clazz == other.clazz &&
					this.serializer.equals(other.serializer);
		} else {
			return false;
		}
	}
}