001/*
002 * Copyright (c) 2016 Chris K Wensel <chris@wensel.net>. All Rights Reserved.
003 * Copyright (c) 2007-2017 Xplenty, Inc. All Rights Reserved.
004 *
005 * Project and contact information: http://www.cascading.org/
006 *
007 * This file is part of the Cascading project.
008 *
009 * Licensed under the Apache License, Version 2.0 (the "License");
010 * you may not use this file except in compliance with the License.
011 * You may obtain a copy of the License at
012 *
013 *     http://www.apache.org/licenses/LICENSE-2.0
014 *
015 * Unless required by applicable law or agreed to in writing, software
016 * distributed under the License is distributed on an "AS IS" BASIS,
017 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
018 * See the License for the specific language governing permissions and
019 * limitations under the License.
020 */
021
022package cascading.flow.hadoop.planner.rule.expression;
023
024import cascading.flow.planner.iso.expression.ElementCapture;
025import cascading.flow.planner.iso.expression.ExpressionGraph;
026import cascading.flow.planner.iso.expression.FlowElementExpression;
027import cascading.flow.planner.iso.expression.JoinEdgesSameSourceScopeExpression;
028import cascading.flow.planner.iso.expression.PathScopeExpression;
029import cascading.flow.planner.iso.expression.TypeExpression;
030import cascading.flow.planner.rule.RuleExpression;
031import cascading.flow.planner.rule.expressiongraph.SyncPipeExpressionGraph;
032import cascading.pipe.HashJoin;
033import cascading.pipe.Pipe;
034import cascading.tap.Tap;
035
036/**
037 *
038 */
039public class BalanceHashJoinSameSourceExpression extends RuleExpression
040  {
041  public BalanceHashJoinSameSourceExpression()
042    {
043    super(
044      new SyncPipeExpressionGraph(),
045
046      new ExpressionGraph()
047        .arc(
048          new FlowElementExpression( ElementCapture.Primary, Tap.class, TypeExpression.Topo.SplitOnly ),
049          JoinEdgesSameSourceScopeExpression.ALL_SAME_SOURCE,
050          new FlowElementExpression( HashJoin.class )
051        ),
052
053      new ExpressionGraph()
054        .arc(
055          new FlowElementExpression( ElementCapture.Secondary, Pipe.class ),
056          PathScopeExpression.BLOCKING,
057          new FlowElementExpression( ElementCapture.Primary, HashJoin.class )
058        )
059    );
060    }
061  }