001/*
002 * Copyright (c) 2007-2022 The Cascading Authors. All Rights Reserved.
003 *
004 * Project and contact information: https://cascading.wensel.net/
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.hadoop.planner.rule.expression;
022
023import cascading.flow.planner.iso.expression.ElementCapture;
024import cascading.flow.planner.iso.expression.ExpressionGraph;
025import cascading.flow.planner.iso.expression.FlowElementExpression;
026import cascading.flow.planner.iso.expression.JoinEdgesSameSourceScopeExpression;
027import cascading.flow.planner.iso.expression.PathScopeExpression;
028import cascading.flow.planner.iso.expression.TypeExpression;
029import cascading.flow.planner.rule.RuleExpression;
030import cascading.flow.planner.rule.expressiongraph.SyncPipeExpressionGraph;
031import cascading.pipe.HashJoin;
032import cascading.pipe.Pipe;
033import cascading.tap.Tap;
034
035/**
036 *
037 */
038public class BalanceHashJoinSameSourceExpression extends RuleExpression
039  {
040  public BalanceHashJoinSameSourceExpression()
041    {
042    super(
043      new SyncPipeExpressionGraph(),
044
045      new ExpressionGraph()
046        .arc(
047          new FlowElementExpression( ElementCapture.Primary, Tap.class, TypeExpression.Topo.SplitOnly ),
048          JoinEdgesSameSourceScopeExpression.ALL_SAME_SOURCE,
049          new FlowElementExpression( HashJoin.class )
050        ),
051
052      new ExpressionGraph()
053        .arc(
054          new FlowElementExpression( ElementCapture.Secondary, Pipe.class ),
055          PathScopeExpression.BLOCKING,
056          new FlowElementExpression( ElementCapture.Primary, HashJoin.class )
057        )
058    );
059    }
060  }