    001/*
    002 * Copyright (c) 2016 Chris K Wensel <chris@wensel.net>. 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.expression;
    022
    023import java.util.Set;
    024
    025import cascading.flow.FlowElement;
    026import cascading.flow.planner.PlannerContext;
    027import cascading.flow.planner.Scope;
    028import cascading.flow.planner.graph.ElementGraph;
    029
    030/**
    031 *
    032 */
    033public class JoinEdgesSameSourceScopeExpression extends ScopeExpression
    034  {
    035  public static final JoinEdgesSameSourceScopeExpression ALL_SAME_SOURCE = new JoinEdgesSameSourceScopeExpression();
    036
    037  public JoinEdgesSameSourceScopeExpression()
    038    {
    039    }
    040
    041  @Override
    042  public boolean applies( PlannerContext plannerContext, ElementGraph elementGraph, Scope scope )
    043    {
    044    FlowElement edgeSource = elementGraph.getEdgeSource( scope );
    045    FlowElement edgeTarget = elementGraph.getEdgeTarget( scope );
    046    Set<Scope> allEdgesBetween = elementGraph.getAllEdges( edgeSource, edgeTarget );
    047
    048    if( allEdgesBetween.size() == 1 )
    049      return false;
    050
    051    return allEdgesBetween.equals( elementGraph.incomingEdgesOf( edgeTarget ) );
    052    }
    053  }