    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.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  }