    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  }