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.ScopeExpression; 028import cascading.flow.planner.iso.expression.TypeExpression.Topo; 029import cascading.flow.planner.rule.RuleExpression; 030import cascading.flow.planner.rule.expressiongraph.SyncPipeExpressionGraph; 031import cascading.pipe.Checkpoint; 032import cascading.pipe.Group; 033import cascading.pipe.HashJoin; 034import cascading.pipe.Pipe; 035import cascading.tap.Tap; 036 037import static cascading.flow.planner.iso.expression.OrElementExpression.or; 038 039/** 040 * 041 */ 042public class BalanceGroupSplitExpression extends RuleExpression 043 { 044 public static final FlowElementExpression SHARED_GROUP = new FlowElementExpression( Group.class, Topo.Split ); 045 046 public BalanceGroupSplitExpression() 047 { 048 super( 049 new SyncPipeExpressionGraph(), 050 051 // in order to capture out degree in sub-graph, we need to capture at least two successors 052 new ExpressionGraph() 053 .arc( 054 SHARED_GROUP, 055 ScopeExpression.ANY, 056 or( new FlowElementExpression( HashJoin.class ), new FlowElementExpression( Group.class ), new FlowElementExpression( Tap.class ), new FlowElementExpression( Checkpoint.class ) ) 057 ) 058 059 .arc( 060 SHARED_GROUP, 061 ScopeExpression.ANY, 062 or( new FlowElementExpression( HashJoin.class ), new FlowElementExpression( Group.class ), new FlowElementExpression( Tap.class ), new FlowElementExpression( Checkpoint.class ) ) 063 ), 064 065 // sub-graph to match has out degree captured above 066 new ExpressionGraph() 067 .arcs( 068 new FlowElementExpression( ElementCapture.Primary, Pipe.class, Topo.SplitOnly ) 069 ) 070 ); 071 } 072 }