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;
031
032/**
033 *
034 */
035public class ContractedGraphTransformer extends MutateGraphTransformer
036  {
037  public ContractedGraphTransformer( ExpressionGraph expression )
038    {
039    super( expression );
040    }
041
042  public ContractedGraphTransformer( GraphTransformer graphTransformer, ExpressionGraph expressionGraph )
043    {
044    super( graphTransformer, expressionGraph );
045    }
046
047  @Override
048  protected boolean transformGraphInPlaceUsing( Transformed<ElementGraph> transformed, ElementGraph graph, Match match )
049    {
050    Set<FlowElement> remove = match.getCapturedElements( ElementCapture.Primary );
051
052    if( remove.isEmpty() )
053      return false;
054
055    for( FlowElement flowElement : remove )
056      ElementGraphs.removeAndContract( graph, flowElement );
057
058    return true;
059    }
060  }