/*
 * 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.runtime.io.network.api;

import org.apache.flink.core.memory.DataInputView;
import org.apache.flink.core.memory.DataOutputView;
import org.apache.flink.runtime.event.RuntimeEvent;

import java.io.IOException;

/**
 * The CancelCheckpointMarker travels through the data streams, similar to the {@link CheckpointBarrier},
 * but signals that a certain checkpoint should be canceled. Any in-progress alignment for that
 * checkpoint needs to be canceled and regular processing should be resumed.
 */
public class CancelCheckpointMarker extends RuntimeEvent {

	/** The id of the checkpoint to be canceled */
	private final long checkpointId;

	public CancelCheckpointMarker(long checkpointId) {
		this.checkpointId = checkpointId;
	}

	public long getCheckpointId() {
		return checkpointId;
	}

	// ------------------------------------------------------------------------
	// These known and common event go through special code paths, rather than
	// through generic serialization 

	@Override
	public void write(DataOutputView out) throws IOException {
		throw new UnsupportedOperationException("this method should never be called");
	}

	@Override
	public void read(DataInputView in) throws IOException {
		throw new UnsupportedOperationException("this method should never be called");
	}
	
	// ------------------------------------------------------------------------

	@Override
	public int hashCode() {
		return (int) (checkpointId ^ (checkpointId >>> 32));
	}

	@Override
	public boolean equals(Object other) {
		return other != null && 
				other.getClass() == CancelCheckpointMarker.class &&
				this.checkpointId == ((CancelCheckpointMarker) other).checkpointId;
	}

	@Override
	public String toString() {
		return "CancelCheckpointMarker " + checkpointId;
	}
}