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.hadoop.planner.rule.expressiongraph;
022
023import cascading.flow.planner.iso.expression.ElementCapture;
024import cascading.flow.planner.iso.expression.ExpressionGraph;
025import cascading.flow.planner.iso.expression.FlowElementExpression;
026import cascading.flow.planner.iso.expression.PathScopeExpression;
027import cascading.flow.planner.iso.expression.TypeExpression;
028import cascading.flow.planner.iso.finder.SearchOrder;
029import cascading.pipe.Group;
030import cascading.pipe.HashJoin;
031import cascading.tap.Tap;
032
033import static cascading.flow.planner.iso.expression.OrElementExpression.or;
034
035/**
036 * Captures the source when the pipeline only has a single source and its streamed.
037 */
038public class StreamedSelfJoinSourcesExpressionGraph extends ExpressionGraph
039  {
040  public StreamedSelfJoinSourcesExpressionGraph()
041    {
042    super( SearchOrder.Depth, true );
043
044    FlowElementExpression intermediate = new FlowElementExpression( HashJoin.class, TypeExpression.Topo.Linear );
045
046    this.arc(
047      or( ElementCapture.Primary,
048        new FlowElementExpression( Tap.class, TypeExpression.Topo.LinearOut ),
049        new FlowElementExpression( Group.class, TypeExpression.Topo.LinearOut )
050      ),
051      PathScopeExpression.ALL,
052      intermediate
053    );
054
055    this.arc(
056      intermediate,
057      PathScopeExpression.ALL,
058      or(
059        new FlowElementExpression( Tap.class ),
060        new FlowElementExpression( Group.class )
061      )
062    );
063    }
064  }