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.finder.SearchOrder;
028import cascading.pipe.Group;
029import cascading.tap.Tap;
030
031import static cascading.flow.planner.iso.expression.OrElementExpression.or;
032
033/**
034 * Captures the source when the pipeline only has a single source and its streamed.
035 */
036public class StreamedOnlySourcesExpressionGraph extends ExpressionGraph
037  {
038  public StreamedOnlySourcesExpressionGraph()
039    {
040    super( SearchOrder.Depth, true );
041
042    this.arc(
043      or( ElementCapture.Primary,
044        new FlowElementExpression( Tap.class ),
045        new FlowElementExpression( Group.class )
046      ),
047      PathScopeExpression.ALL,
048      or(
049        new FlowElementExpression( Tap.class ),
050        new FlowElementExpression( Group.class )
051      )
052    );
053    }
054  }