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.planner.iso.transformer; 022 023import java.util.Set; 024 025import cascading.flow.FlowElement; 026import cascading.flow.planner.graph.ElementGraph; 027import cascading.flow.planner.graph.ElementGraphs; 028import cascading.flow.planner.iso.expression.ElementCapture; 029import cascading.flow.planner.iso.expression.ExpressionGraph; 030import cascading.flow.planner.iso.finder.Match; 031import cascading.util.Util; 032 033/** 034 * 035 */ 036public class ReplaceGraphTransformer extends MutateGraphTransformer 037 { 038 public ReplaceGraphTransformer( ExpressionGraph filter ) 039 { 040 super( filter ); 041 } 042 043 public ReplaceGraphTransformer( GraphTransformer graphTransformer, ExpressionGraph filter ) 044 { 045 super( graphTransformer, filter ); 046 } 047 048 @Override 049 protected boolean transformGraphInPlaceUsing( Transformed<ElementGraph> transformed, ElementGraph graph, Match match ) 050 { 051 Set<FlowElement> replace = match.getCapturedElements( ElementCapture.Primary ); 052 Set<FlowElement> replaceWith = match.getCapturedElements( ElementCapture.Secondary ); 053 054 if( replace.isEmpty() || replaceWith.isEmpty() ) 055 return false; 056 057 if( replace.size() != 1 ) 058 throw new IllegalStateException( "too many captured elements" ); 059 060 if( replaceWith.size() != 1 ) 061 throw new IllegalStateException( "too many target elements" ); 062 063 ElementGraphs.replaceElementWith( graph, Util.getFirst( replace ), Util.getFirst( replaceWith ) ); 064 065 return true; 066 } 067 }