/**
* Copyright (c) 2013, Institute of Information Systems (Sven Groppe and contributors of LUPOSDATE), University of Luebeck
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
* following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice, this list of conditions and the following
* disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
* following disclaimer in the documentation and/or other materials provided with the distribution.
* - Neither the name of the University of Luebeck nor the names of its contributors may be used to endorse or promote
* products derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package lupos.optimizations.logical.rules.parallel;
import java.util.Map;
import lupos.engine.operators.BasicOperator;
import lupos.engine.operators.OperatorIDTuple;
import lupos.engine.operators.SimpleOperatorGraphVisitor;
import lupos.engine.operators.multiinput.join.Join;
import lupos.engine.operators.multiinput.optional.Optional;
import lupos.engine.operators.singleinput.parallel.ParallelOperand;
/**
* Implements a graph transformation which inserts a {@link ParallelOperand}
* between each {@link Join} operator and its arguments, effectively evaluating
* in a separate thread and thus distributing it across possibly multiple
* processors.
*
* @see ParallelOperand
*/
public class RuleJoinLastParallelOperands extends RuleJoinWithParallelOperands {
private boolean checkRecursiveForJoinOrOptional(final BasicOperator op) {
for (final OperatorIDTuple sop : op.getSucceedingOperators()) {
final FindJoinOrOptionalOperatorVisitor frov = new FindJoinOrOptionalOperatorVisitor();
sop.getOperator().visit(frov);
if (frov.found())
return true;
}
return false;
}
@Override
protected boolean checkPrecondition(final Map<String, BasicOperator> mso) {
final BasicOperator join = mso.get("join");
return !checkRecursiveForJoinOrOptional(join)
&& super.checkPrecondition(mso);
}
@Override
public String getName() {
return "JoinLastParallelOperands";
}
private class FindJoinOrOptionalOperatorVisitor implements SimpleOperatorGraphVisitor {
private boolean found = false;
public Object visit(final BasicOperator basicOperator) {
if (basicOperator instanceof Join
|| basicOperator instanceof Optional)
found = true;
return null;
}
public boolean found() {
return found;
}
}
}