    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.hadoop.planner.rule.expression;
    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.JoinEdgesSameSourceScopeExpression;
    028import cascading.flow.planner.iso.expression.PathScopeExpression;
    029import cascading.flow.planner.iso.expression.TypeExpression;
    030import cascading.flow.planner.rule.RuleExpression;
    031import cascading.flow.planner.rule.expressiongraph.SyncPipeExpressionGraph;
    032import cascading.pipe.HashJoin;
    033import cascading.pipe.Pipe;
    034import cascading.tap.Tap;
    035
    036/**
    037 *
    038 */
    039public class BalanceHashJoinSameSourceExpression extends RuleExpression
    040  {
    041  public BalanceHashJoinSameSourceExpression()
    042    {
    043    super(
    044      new SyncPipeExpressionGraph(),
    045
    046      new ExpressionGraph()
    047        .arc(
    048          new FlowElementExpression( ElementCapture.Primary, Tap.class, TypeExpression.Topo.SplitOnly ),
    049          JoinEdgesSameSourceScopeExpression.ALL_SAME_SOURCE,
    050          new FlowElementExpression( HashJoin.class )
    051        ),
    052
    053      new ExpressionGraph()
    054        .arc(
    055          new FlowElementExpression( ElementCapture.Secondary, Pipe.class ),
    056          PathScopeExpression.BLOCKING,
    057          new FlowElementExpression( ElementCapture.Primary, HashJoin.class )
    058        )
    059    );
    060    }
    061  }