001/*
002 * Copyright (c) 2007-2017 Xplenty, 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 cascading.flow.planner.graph.ElementGraph;
024import cascading.flow.planner.iso.expression.ExpressionGraph;
025import cascading.util.ProcessLogger;
026
027/**
028 *
029 */
030public abstract class MutateGraphTransformer extends RecursiveGraphTransformer<ElementGraph>
031  {
032  protected final GraphTransformer graphTransformer;
033
034  public MutateGraphTransformer( ExpressionGraph filter )
035    {
036    super( filter );
037    this.graphTransformer = null;
038    }
039
040  public MutateGraphTransformer( GraphTransformer graphTransformer, ExpressionGraph filter )
041    {
042    super( filter );
043    this.graphTransformer = graphTransformer;
044    }
045
046  @Override
047  protected boolean requiresRecursiveSearch()
048    {
049    return graphTransformer != null || super.requiresRecursiveSearch();
050    }
051
052  @Override
053  protected ElementGraph prepareForMatch( ProcessLogger processLogger, Transformed<ElementGraph> transformed, ElementGraph graph )
054    {
055    if( graphTransformer == null )
056      return graph;
057
058    if( processLogger.isDebugEnabled() )
059      processLogger.logDebug( "transforming with: {}", graphTransformer.getClass().getSimpleName() );
060
061    Transformed child = graphTransformer.transform( transformed.getPlannerContext(), graph );
062
063    transformed.addChildTransform( child );
064
065    return child.getEndGraph();
066    }
067  }