flink-optimizer/src/main/java/org/apache/flink/optimizer/operators/CrossStreamOuterSecondDescriptor.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.optimizer.operators;

import org.apache.flink.optimizer.dataproperties.LocalProperties;
import org.apache.flink.runtime.operators.DriverStrategy;


public class CrossStreamOuterSecondDescriptor extends CartesianProductDescriptor {
	
	public CrossStreamOuterSecondDescriptor() {
		this(true, true);
	}
	
	public CrossStreamOuterSecondDescriptor(boolean allowBroadcastFirst, boolean allowBroadcastSecond) {
		super(allowBroadcastFirst, allowBroadcastSecond);
	}
	
	@Override
	public DriverStrategy getStrategy() {
		return DriverStrategy.NESTEDLOOP_STREAMED_OUTER_SECOND;
	}

	@Override
	public LocalProperties computeLocalProperties(LocalProperties in1, LocalProperties in2) {
		// uniqueness becomes grouping with streamed nested loops
		if ((in2.getGroupedFields() == null || in2.getGroupedFields().size() == 0) &&
				in2.getUniqueFields() != null && in2.getUniqueFields().size() > 0)
		{
			return LocalProperties.forGrouping(in2.getUniqueFields().iterator().next().toFieldList());
		} else {
			return in2.clearUniqueFieldSets();
		}
	}
}