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.planner.rule; 022 023import cascading.flow.planner.PlannerContext; 024import cascading.flow.planner.graph.ElementGraph; 025import cascading.flow.planner.iso.transformer.ContractedTransformer; 026import cascading.flow.planner.iso.transformer.GraphTransformer; 027import cascading.flow.planner.iso.transformer.RecursiveGraphTransformer; 028import cascading.flow.planner.iso.transformer.SubGraphTransformer; 029import cascading.flow.planner.iso.transformer.Transformed; 030 031/** 032 * The RuleTransformer class is responsible for transforming an element graph into a new graph. 033 */ 034public class RuleTransformer extends GraphTransformer<ElementGraph, ElementGraph> implements Rule 035 { 036 private final PlanPhase phase; 037 protected final RuleExpression ruleExpression; 038 protected final ContractedTransformer contractedTransformer; 039 protected final SubGraphTransformer subGraphTransformer; 040 041 protected RecursiveGraphTransformer<ElementGraph> graphTransformer; 042 043 public RuleTransformer( PlanPhase phase, RuleExpression ruleExpression ) 044 { 045 this.phase = phase; 046 this.ruleExpression = ruleExpression; 047 048 if( ruleExpression.getContractionExpression() != null ) 049 contractedTransformer = new ContractedTransformer( ruleExpression.getContractionExpression() ); 050 else 051 contractedTransformer = null; 052 053 if( ruleExpression.getContractedMatchExpression() != null ) 054 { 055 if( contractedTransformer == null ) 056 throw new IllegalArgumentException( "must have contracted expression if given contracted match expression" ); 057 058 subGraphTransformer = new SubGraphTransformer( contractedTransformer, ruleExpression.getContractedMatchExpression() ); 059 } 060 else 061 { 062 subGraphTransformer = null; 063 } 064 } 065 066 @Override 067 public PlanPhase getRulePhase() 068 { 069 return phase; 070 } 071 072 @Override 073 public String getRuleName() 074 { 075 return getClass().getSimpleName().replaceAll( "^(.*)[]A-Z][a-z]*Rule$", "$1" ); 076 } 077 078 @Override 079 public Transformed<ElementGraph> transform( PlannerContext plannerContext, ElementGraph rootGraph ) 080 { 081 Transformed<ElementGraph> result = new Transformed<>( plannerContext, this, rootGraph ); 082 083 ElementGraph graphCopy = rootGraph.copyElementGraph(); 084 085 Transformed<ElementGraph> transformed = graphTransformer.transform( plannerContext, graphCopy ); 086 087 result.addChildTransform( transformed ); 088 089 if( transformed.getEndGraph() != null && !rootGraph.equals( transformed.getEndGraph() ) ) 090 result.setEndGraph( transformed.getEndGraph() ); 091 092 return result; 093 } 094 095 @Override 096 public String toString() 097 { 098 return getRuleName(); 099 } 100 }