flink-core/src/main/java/org/apache/flink/api/common/typeutils/ParameterlessTypeSerializerConfig.java

/*
 * 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;

/**
 * A base class for {@link TypeSerializerConfigSnapshot}s that do not have any parameters.
 */
@Internal
public final class ParameterlessTypeSerializerConfig extends TypeSerializerConfigSnapshot {

	private static final int VERSION = 1;

	/**
	 * A string identifier that encodes the serialization format used by the serializer.
	 *
	 * TODO we might change this to a proper serialization format class in the future
	 */
	private String serializationFormatIdentifier;

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

	public ParameterlessTypeSerializerConfig(String serializationFormatIdentifier) {
		this.serializationFormatIdentifier = Preconditions.checkNotNull(serializationFormatIdentifier);
	}

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

	@Override
	public void read(DataInputView in) throws IOException {
		super.read(in);
		serializationFormatIdentifier = in.readUTF();
	}

	@Override
	public int getVersion() {
		return VERSION;
	}

	public String getSerializationFormatIdentifier() {
		return serializationFormatIdentifier;
	}

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

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

		return (other instanceof ParameterlessTypeSerializerConfig)
				&& serializationFormatIdentifier.equals(((ParameterlessTypeSerializerConfig) other).getSerializationFormatIdentifier());
	}

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