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An API for data management, analytics, and machine learning on parallel computing clusters.

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/*
 * Copyright (c) 2007-2017 Xplenty, Inc. All Rights Reserved.
 *
 * Project and contact information: http://www.cascading.org/
 *
 * This file is part of the Cascading project.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cascading.flow.hadoop.planner.rule.expressiongraph;

import cascading.flow.planner.iso.expression.ElementCapture;
import cascading.flow.planner.iso.expression.ExpressionGraph;
import cascading.flow.planner.iso.expression.FlowElementExpression;
import cascading.flow.planner.iso.expression.PathScopeExpression;
import cascading.flow.planner.iso.expression.TypeExpression;
import cascading.flow.planner.iso.finder.SearchOrder;
import cascading.pipe.Group;
import cascading.pipe.HashJoin;
import cascading.tap.Tap;

import static cascading.flow.planner.iso.expression.OrElementExpression.or;

/**
 * Captures the source when the pipeline only has a single source and its streamed.
 */
public class StreamedSelfJoinSourcesExpressionGraph extends ExpressionGraph
  {
  public StreamedSelfJoinSourcesExpressionGraph()
    {
    super( SearchOrder.Depth, true );

    FlowElementExpression intermediate = new FlowElementExpression( HashJoin.class, TypeExpression.Topo.Linear );

    this.arc(
      or( ElementCapture.Primary,
        new FlowElementExpression( Tap.class, TypeExpression.Topo.LinearOut ),
        new FlowElementExpression( Group.class, TypeExpression.Topo.LinearOut )
      ),
      PathScopeExpression.ALL,
      intermediate
    );

    this.arc(
      intermediate,
      PathScopeExpression.ALL,
      or(
        new FlowElementExpression( Tap.class ),
        new FlowElementExpression( Group.class )
      )
    );
    }
  }