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.NonSafeOperationExpression; 027import cascading.flow.planner.iso.expression.TypeExpression; 028import cascading.flow.planner.rule.RuleExpression; 029import cascading.flow.planner.rule.expressiongraph.NonSafeAndSplitAndSyncPipeExpressionGraph; 030import cascading.pipe.Pipe; 031import cascading.tap.Tap; 032 033/** 034 * Captures a split against a non-safe Operation to prevent the operation from running 035 * in parallel mappers. 036 * <p/> 037 * THis variant allows a non-safe operation to be followed by any Pipe. this assumes other rules 038 * enforce splitting to only be on Each or Pipe types. 039 */ 040public class BalanceNonSafePipeSplitExpression extends RuleExpression 041 { 042 public BalanceNonSafePipeSplitExpression() 043 { 044 super( 045 new NonSafeAndSplitAndSyncPipeExpressionGraph(), 046 047 new ExpressionGraph() 048 .arcs( 049 new FlowElementExpression( Tap.class ), 050 new NonSafeOperationExpression(), 051 new FlowElementExpression( Pipe.class, TypeExpression.Topo.SplitOnly ) 052 ), 053 054 new ExpressionGraph() 055 .arcs( 056 new FlowElementExpression( ElementCapture.Primary, Pipe.class, TypeExpression.Topo.Tail ) 057 ) 058 ); 059 } 060 }