/***********************************************************************************************************************
 * Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
 *
 * Licensed 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 eu.stratosphere.compiler.operators;

import java.util.ArrayList;
import java.util.List;

import eu.stratosphere.api.common.operators.util.FieldList;
import eu.stratosphere.compiler.dataproperties.GlobalProperties;
import eu.stratosphere.compiler.dataproperties.PartitioningProperty;
import eu.stratosphere.compiler.dataproperties.RequestedGlobalProperties;


public abstract class AbstractJoinDescriptor extends OperatorDescriptorDual {
	
	protected AbstractJoinDescriptor(FieldList keys1, FieldList keys2) {
		super(keys1, keys2);
	}
	
	@Override
	protected List<GlobalPropertiesPair> createPossibleGlobalProperties() {
		ArrayList<GlobalPropertiesPair> pairs = new ArrayList<GlobalPropertiesPair>();
		
		{ // partition both (hash)
			RequestedGlobalProperties partitioned1 = new RequestedGlobalProperties();
			partitioned1.setHashPartitioned(this.keys1);
			RequestedGlobalProperties partitioned2 = new RequestedGlobalProperties();
			partitioned2.setHashPartitioned(this.keys2);
			pairs.add(new GlobalPropertiesPair(partitioned1, partitioned2));
		}
		{ // replicate second
			RequestedGlobalProperties any1 = new RequestedGlobalProperties();
			RequestedGlobalProperties replicated2 = new RequestedGlobalProperties();
			replicated2.setFullyReplicated();
			pairs.add(new GlobalPropertiesPair(any1, replicated2));
		}
		{ // replicate first
			RequestedGlobalProperties replicated1 = new RequestedGlobalProperties();
			replicated1.setFullyReplicated();
			RequestedGlobalProperties any2 = new RequestedGlobalProperties();
			pairs.add(new GlobalPropertiesPair(replicated1, any2));
		}
		return pairs;
	}

	@Override
	public GlobalProperties computeGlobalProperties(GlobalProperties in1, GlobalProperties in2) {
		GlobalProperties gp = GlobalProperties.combine(in1, in2);
		if (gp.getUniqueFieldCombination() != null && gp.getUniqueFieldCombination().size() > 0 &&
					gp.getPartitioning() == PartitioningProperty.RANDOM)
		{
			gp.setAnyPartitioning(gp.getUniqueFieldCombination().iterator().next().toFieldList());
		}
		gp.clearUniqueFieldCombinations();
		return gp;
	}
}