/*
 * 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.common.typeutils;

import org.apache.flink.annotation.Internal;
import org.apache.flink.core.memory.DataInputView;
import org.apache.flink.core.memory.DataOutputView;
import org.apache.flink.util.Preconditions;

import java.io.IOException;

/**
 * Configuration snapshot for serializers for generic types.
 *
 * @param <T> The type to be instantiated.
 */
@Internal
public abstract class GenericTypeSerializerConfigSnapshot<T> extends TypeSerializerConfigSnapshot {

	private Class<T> typeClass;

	/** This empty nullary constructor is required for deserializing the configuration. */
	public GenericTypeSerializerConfigSnapshot() {}

	public GenericTypeSerializerConfigSnapshot(Class<T> typeClass) {
		this.typeClass = Preconditions.checkNotNull(typeClass);
	}

	@Override
	public void write(DataOutputView out) throws IOException {
		super.write(out);

		// write only the classname to avoid Java serialization
		out.writeUTF(typeClass.getName());
	}

	@SuppressWarnings("unchecked")
	@Override
	public void read(DataInputView in) throws IOException {
		super.read(in);

		String genericTypeClassname = in.readUTF();
		try {
			typeClass = (Class<T>) Class.forName(genericTypeClassname, true, getUserCodeClassLoader());
		} catch (ClassNotFoundException e) {
			throw new IOException("Could not find the requested class " + genericTypeClassname + " in classpath.", e);
		}
	}

	public Class<T> getTypeClass() {
		return typeClass;
	}

	@Override
	public boolean equals(Object obj) {
		if (obj == this) {
			return true;
		}

		if (obj == null) {
			return false;
		}

		return (obj.getClass().equals(getClass()))
				&& typeClass.equals(((GenericTypeSerializerConfigSnapshot) obj).getTypeClass());
	}

	@Override
	public int hashCode() {
		return typeClass.hashCode();
	}
}