/***********************************************************************************************************************
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* 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 eu.stratosphere.compiler.dag;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import eu.stratosphere.compiler.CompilerException;
import eu.stratosphere.compiler.DataStatistics;
import eu.stratosphere.compiler.operators.OperatorDescriptorDual;
import eu.stratosphere.compiler.operators.UtilSinkJoinOpDescriptor;
import eu.stratosphere.compiler.util.NoOpBinaryUdfOp;
import eu.stratosphere.types.Nothing;
import eu.stratosphere.types.NothingTypeInfo;
/**
* This class represents a utility node that is not part of the actual plan. It is used for plans with multiple data sinks to
* transform it into a plan with a single root node. That way, the code that makes sure no costs are double-counted and that
* candidate selection works correctly with nodes that have multiple outputs is transparently reused.
*/
public class SinkJoiner extends TwoInputNode {
public SinkJoiner(OptimizerNode input1, OptimizerNode input2) {
super(new NoOpBinaryUdfOp<Nothing>(new NothingTypeInfo()));
PactConnection conn1 = new PactConnection(input1, this);
PactConnection conn2 = new PactConnection(input2, this);
this.input1 = conn1;
this.input2 = conn2;
setDegreeOfParallelism(1);
setSubtasksPerInstance(1);
}
@Override
public String getName() {
return "Internal Utility Node";
}
@Override
public List<PactConnection> getOutgoingConnections() {
return Collections.emptyList();
}
@Override
public void computeUnclosedBranchStack() {
if (this.openBranches != null) {
return;
}
addClosedBranches(getFirstPredecessorNode().closedBranchingNodes);
addClosedBranches(getSecondPredecessorNode().closedBranchingNodes);
List<UnclosedBranchDescriptor> pred1branches = getFirstPredecessorNode().openBranches;
List<UnclosedBranchDescriptor> pred2branches = getSecondPredecessorNode().openBranches;
// if the predecessors do not have branches, then we have multiple sinks that do not originate from
// a common data flow.
if (pred1branches == null || pred1branches.isEmpty() || pred2branches == null || pred2branches.isEmpty()) {
throw new CompilerException("The given program contains multiple disconnected data flows.");
}
// copy the lists and merge
List<UnclosedBranchDescriptor> result1 = new ArrayList<UnclosedBranchDescriptor>(pred1branches);
List<UnclosedBranchDescriptor> result2 = new ArrayList<UnclosedBranchDescriptor>(pred2branches);
ArrayList<UnclosedBranchDescriptor> result = new ArrayList<UnclosedBranchDescriptor>();
mergeLists(result1, result2, result);
// if (!didCloseSomeBranch) {
// // if the sink joiners do not close branches, then we have disjoint data flows.
// throw new CompilerException("The given program contains multiple disconnected data flows.");
// }
this.openBranches = result.isEmpty() ? Collections.<UnclosedBranchDescriptor>emptyList() : result;
}
@Override
protected List<OperatorDescriptorDual> getPossibleProperties() {
return Collections.<OperatorDescriptorDual>singletonList(new UtilSinkJoinOpDescriptor());
}
@Override
public void computeOutputEstimates(DataStatistics statistics) {
// nothing to be done here
}
@Override
protected void computeOperatorSpecificDefaultEstimates(DataStatistics statistics) {
// no estimates needed at this point
}
}