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.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.PathScopeExpression; 027import cascading.flow.planner.iso.expression.TypeExpression; 028import cascading.flow.planner.rule.RuleExpression; 029import cascading.flow.planner.rule.expressiongraph.SyncPipeExpressionGraph; 030import cascading.pipe.HashJoin; 031import cascading.pipe.Pipe; 032import cascading.tap.Tap; 033 034/** 035 * 036 */ 037public class BalanceHashJoinSameSourceExpression extends RuleExpression 038 { 039 private static final FlowElementExpression SHARED_TAP = new FlowElementExpression( Tap.class, TypeExpression.Topo.SplitOnly ); 040 public static final FlowElementExpression SHARED_HASHJOIN = new FlowElementExpression( HashJoin.class ); 041 042 public BalanceHashJoinSameSourceExpression() 043 { 044 super( 045 new SyncPipeExpressionGraph(), 046 047 new ExpressionGraph() 048 .arcs( SHARED_TAP, SHARED_HASHJOIN ) 049 .arcs( SHARED_TAP, SHARED_HASHJOIN ), 050 051 new ExpressionGraph() 052 .arc( 053 new FlowElementExpression( ElementCapture.Secondary, Pipe.class ), 054 PathScopeExpression.BLOCKING, 055 new FlowElementExpression( ElementCapture.Primary, HashJoin.class ) 056 ) 057 ); 058 } 059 }