001/*
002 * Copyright (c) 2007-2016 Concurrent, Inc. All Rights Reserved.
003 *
004 * Project and contact information: http://www.cascading.org/
005 *
006 * This file is part of the Cascading project.
007 *
008 * Licensed under the Apache License, Version 2.0 (the "License");
009 * you may not use this file except in compliance with the License.
010 * You may obtain a copy of the License at
011 *
012 *     http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing, software
015 * distributed under the License is distributed on an "AS IS" BASIS,
016 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
017 * See the License for the specific language governing permissions and
018 * limitations under the License.
019 */
020
021package cascading.flow.tez.planner.rule.transformer;
022
023import cascading.flow.planner.iso.expression.ElementCapture;
024import cascading.flow.planner.rule.transformer.BoundaryElementFactory;
025import cascading.flow.planner.rule.transformer.RuleInsertionTransformer;
026import cascading.flow.tez.planner.rule.expression.BalanceSplitToStreamedHashJoinExpression;
027
028import static cascading.flow.planner.rule.PlanPhase.BalanceAssembly;
029
030/**
031 * Inserts Boundary after split that joins back into a HashJoin.
032 * <p/>
033 * this allows testGroupBySplitGroupByJoin to pass, and simplifies testJoinSamePipeAroundGroupBy by preventing
034 * the upstream operations to duplicate processing in parallel nodes
035 */
036public class BoundaryBalanceSplitToStreamedHashJoinTransformer extends RuleInsertionTransformer
037  {
038  public BoundaryBalanceSplitToStreamedHashJoinTransformer()
039    {
040    super(
041      BalanceAssembly,
042      new BalanceSplitToStreamedHashJoinExpression(),
043      ElementCapture.Secondary,
044      BoundaryElementFactory.BOUNDARY_PIPE
045    );
046    }
047  }