001/* 002 * Copyright (c) 2007-2017 Xplenty, 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.rule.RuleExpression; 027import cascading.flow.planner.rule.expressiongraph.SplicePipeExpressionGraph; 028import cascading.pipe.Group; 029import cascading.pipe.Merge; 030import cascading.pipe.Pipe; 031 032/** 033 * 034 */ 035public class BalanceGroupSplitMergeGroupExpression extends RuleExpression 036 { 037 public static final FlowElementExpression GROUP = new FlowElementExpression( Group.class ); 038 public static final FlowElementExpression MERGE = new FlowElementExpression( Merge.class ); 039 040 public BalanceGroupSplitMergeGroupExpression() 041 { 042 super( 043 new SplicePipeExpressionGraph(), 044 045 new ExpressionGraph() 046 .arcs( 047 GROUP, 048 MERGE ) 049 .arcs( 050 GROUP, 051 MERGE ) 052 .arcs( 053 MERGE, 054 new FlowElementExpression( Group.class ) ), 055 056 new ExpressionGraph() 057 .arcs( 058 new FlowElementExpression( ElementCapture.Primary, Pipe.class ), 059 new FlowElementExpression( Group.class ) 060 ) 061 ); 062 } 063 }