    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.expression;
    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.rule.RuleExpression;
    028import cascading.flow.planner.rule.expressiongraph.SyncPipeExpressionGraph;
    029import cascading.pipe.Group;
    030import cascading.pipe.HashJoin;
    031import cascading.pipe.Pipe;
    032
    033/**
    034 *
    035 */
    036public class BalanceGroupBlockingHashJoinExpression extends RuleExpression
    037  {
    038  public BalanceGroupBlockingHashJoinExpression()
    039    {
    040    super(
    041      new SyncPipeExpressionGraph(),
    042
    043      new ExpressionGraph()
    044        .arc(
    045          new FlowElementExpression( Group.class ),
    046          PathScopeExpression.BLOCKING,
    047          new FlowElementExpression( HashJoin.class )
    048        ),
    049
    050      new ExpressionGraph()
    051        .arc(
    052          new FlowElementExpression( ElementCapture.Primary, Pipe.class ),
    053          PathScopeExpression.BLOCKING,
    054          new FlowElementExpression( HashJoin.class )
    055        )
    056    );
    057    }
    058  }