/*
 * 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.optimizer.dag;

/**
 * Enumeration to indicate the mode of temporarily materializing the data that flows across a connection.
 * Introducing such an artificial dam is sometimes necessary to avoid that a certain data flows deadlock
 * themselves, or as a cache to replay an intermediate result.
 */
public enum TempMode {
	
	NONE(false, false),
	PIPELINE_BREAKER(false, true),
	CACHED(true, false),
	CACHING_PIPELINE_BREAKER(true, true);
	
	// --------------------------------------------------------------------------------------------
	
	private final boolean cached;
	
	private final boolean breaksPipeline;
	
	
	private TempMode(boolean cached, boolean breaksPipeline) {
		this.cached = cached;
		this.breaksPipeline = breaksPipeline;
	}

	public boolean isCached() {
		return cached;
	}

	public boolean breaksPipeline() {
		return breaksPipeline;
	}
	
	public TempMode makePipelineBreaker() {
		if (this == NONE) {
			return PIPELINE_BREAKER;
		} else if (this == CACHED) {
			return CACHING_PIPELINE_BREAKER;
		} else {
			return this;
		}
	}
	
	public TempMode makeCached() {
		if (this == NONE) {
			return CACHED;
		} else if (this == PIPELINE_BREAKER) {
			return CACHING_PIPELINE_BREAKER;
		} else {
			return this;
		}
	}
	
	
	public TempMode makeNonCached() {
		if (this == CACHED) {
			return NONE;
		} else if (this == CACHING_PIPELINE_BREAKER) {
			return PIPELINE_BREAKER;
		} else {
			return this;
		}
	}
}