    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;
    031import cascading.util.Util;
    032
    033/**
    034 *
    035 */
    036public class RemoveBranchGraphTransformer extends MutateGraphTransformer
    037  {
    038  public RemoveBranchGraphTransformer( ExpressionGraph filter )
    039    {
    040    super( filter );
    041    }
    042
    043  public RemoveBranchGraphTransformer( 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> primary = match.getCapturedElements( ElementCapture.Primary );
    052    Set<FlowElement> secondary = match.getCapturedElements( ElementCapture.Secondary );
    053
    054    if( primary.isEmpty() )
    055      return false;
    056
    057    if( primary.size() != 1 )
    058      throw new IllegalStateException( "too many captured primary elements" );
    059
    060    if( secondary.isEmpty() )
    061      {
    062      boolean found = ElementGraphs.removeBranchContaining( graph, Util.getFirst( primary ) );
    063
    064      if( !found )
    065        throw new IllegalStateException( "no branch found at: " + Util.getFirst( primary ) );
    066      }
    067    else
    068      {
    069      if( secondary.size() != 1 )
    070        throw new IllegalStateException( "too many captured secondary elements" );
    071
    072      boolean found = ElementGraphs.removeBranchBetween( graph, Util.getFirst( primary ), Util.getFirst( secondary ), false );
    073
    074      if( !found )
    075        throw new IllegalStateException( "no branch found at: " + Util.getFirst( primary ) );
    076      }
    077
    078    return true;
    079    }
    080  }