    001/*
    002 * Copyright (c) 2016 Chris K Wensel <chris@wensel.net>. All Rights Reserved.
    003 * Copyright (c) 2007-2017 Xplenty, Inc. All Rights Reserved.
    004 *
    005 * Project and contact information: http://www.cascading.org/
    006 *
    007 * This file is part of the Cascading project.
    008 *
    009 * Licensed under the Apache License, Version 2.0 (the "License");
    010 * you may not use this file except in compliance with the License.
    011 * You may obtain a copy of the License at
    012 *
    013 *     http://www.apache.org/licenses/LICENSE-2.0
    014 *
    015 * Unless required by applicable law or agreed to in writing, software
    016 * distributed under the License is distributed on an "AS IS" BASIS,
    017 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    018 * See the License for the specific language governing permissions and
    019 * limitations under the License.
    020 */
    021
    022package cascading.flow.tez.planner.rule.expressiongraph;
    023
    024import cascading.flow.planner.iso.expression.ElementCapture;
    025import cascading.flow.planner.iso.expression.ExpressionGraph;
    026import cascading.flow.planner.iso.expression.FlowElementExpression;
    027import cascading.flow.planner.iso.expression.PathScopeExpression;
    028import cascading.flow.planner.iso.expression.TypeExpression.Topo;
    029import cascading.flow.planner.iso.finder.SearchOrder;
    030import cascading.flow.planner.rule.elementexpression.BoundariesElementExpression;
    031import cascading.tap.Tap;
    032
    033import static cascading.flow.planner.iso.expression.AndElementExpression.and;
    034import static cascading.flow.planner.iso.expression.NotElementExpression.not;
    035
    036/**
    037 *
    038 */
    039public class TopDownSplitJoinBoundariesExpressionGraph extends ExpressionGraph
    040  {
    041  public TopDownSplitJoinBoundariesExpressionGraph()
    042    {
    043    super( SearchOrder.Topological );
    044
    045    this.arc(
    046      new BoundariesElementExpression( Topo.Split ),
    047
    048      PathScopeExpression.ANY,
    049
    050      // don't capture a contracted graph having a tap split to a splice tap (two taps with two edges)
    051      // this interferes if there is a logical split and merge
    052      and(
    053        ElementCapture.Primary,
    054        new BoundariesElementExpression( Topo.Splice ),
    055        not( new FlowElementExpression( Tap.class ) )
    056      )
    057    );
    058    }
    059  }