001/* 002 * Copyright (c) 2007-2015 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.scopeexpression; 022 023import java.net.URI; 024 025import cascading.flow.FlowElement; 026import cascading.flow.hadoop.planner.HadoopPlanner; 027import cascading.flow.planner.PlannerContext; 028import cascading.flow.planner.Scope; 029import cascading.flow.planner.graph.ElementGraph; 030import cascading.flow.planner.iso.expression.ScopeExpression; 031import cascading.tap.hadoop.Hfs; 032 033/** 034 * 035 */ 036public class EquivalentTapsScopeExpression extends ScopeExpression 037 { 038 @Override 039 public boolean applies( PlannerContext plannerContext, ElementGraph elementGraph, Scope scope ) 040 { 041 FlowElement edgeSource = elementGraph.getEdgeSource( scope ); 042 FlowElement edgeTarget = elementGraph.getEdgeTarget( scope ); 043 044 if( !( edgeSource instanceof Hfs ) || !( edgeTarget instanceof Hfs ) ) 045 throw new IllegalStateException( "non Hfs Taps matched" ); 046 047 Hfs predecessor = (Hfs) edgeSource; 048 Hfs successor = (Hfs) edgeTarget; 049 050 // does this scheme source what it sinks 051 if( !successor.getScheme().isSymmetrical() ) 052 return false; 053 054 HadoopPlanner flowPlanner = (HadoopPlanner) plannerContext.getFlowPlanner(); 055 056 URI tempURIScheme = flowPlanner.getDefaultURIScheme( predecessor ); // temp uses default fs 057 URI successorURIScheme = flowPlanner.getURIScheme( successor ); 058 059 if( !tempURIScheme.equals( successorURIScheme ) ) 060 return false; 061 062 // safe, both are symmetrical 063 // should be called after fields are resolved 064 if( !predecessor.getSourceFields().equals( successor.getSourceFields() ) ) 065 return true; 066 067 return true; 068 } 069 }