Java tutorial
/* * Copyright 2009-2013 by The Regents of the University of California * 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 from * * 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 edu.uci.ics.hyracks.algebricks.rewriter.rules; import java.util.HashSet; import java.util.ListIterator; import java.util.Set; import org.apache.commons.lang3.mutable.Mutable; import org.apache.commons.lang3.mutable.MutableObject; import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException; import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalExpression; import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator; import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalPlan; import edu.uci.ics.hyracks.algebricks.core.algebra.base.IOptimizationContext; import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalOperatorTag; import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable; import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.ConstantExpression; import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.AbstractLogicalOperator; import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.InnerJoinOperator; import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.NestedTupleSourceOperator; import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.SubplanOperator; import edu.uci.ics.hyracks.algebricks.core.algebra.util.OperatorManipulationUtil; import edu.uci.ics.hyracks.algebricks.core.algebra.util.OperatorPropertiesUtil; public class IntroJoinInsideSubplanRule extends AbstractDecorrelationRule { @Override public boolean rewritePost(Mutable<ILogicalOperator> opRef, IOptimizationContext context) throws AlgebricksException { AbstractLogicalOperator op0 = (AbstractLogicalOperator) opRef.getValue(); if (op0.getOperatorTag() != LogicalOperatorTag.SUBPLAN) { return false; } SubplanOperator subplan = (SubplanOperator) op0; Mutable<ILogicalOperator> leftRef = subplan.getInputs().get(0); if (((AbstractLogicalOperator) leftRef.getValue()) .getOperatorTag() == LogicalOperatorTag.EMPTYTUPLESOURCE) { return false; } ListIterator<ILogicalPlan> plansIter = subplan.getNestedPlans().listIterator(); ILogicalPlan p = null; while (plansIter.hasNext()) { p = plansIter.next(); } if (p == null) { return false; } if (p.getRoots().size() != 1) { return false; } Mutable<ILogicalOperator> opRef1 = p.getRoots().get(0); while (true) { AbstractLogicalOperator op1 = (AbstractLogicalOperator) opRef1.getValue(); if (op1.getInputs().size() != 1) { return false; } if (op1.getOperatorTag() == LogicalOperatorTag.SELECT) { Mutable<ILogicalOperator> op2Ref = op1.getInputs().get(0); AbstractLogicalOperator op2 = (AbstractLogicalOperator) op2Ref.getValue(); if (op2.getOperatorTag() != LogicalOperatorTag.SELECT && descOrSelfIsScanOrJoin(op2)) { Set<LogicalVariable> free2 = new HashSet<LogicalVariable>(); OperatorPropertiesUtil.getFreeVariablesInSelfOrDesc(op2, free2); if (free2.isEmpty()) { Set<LogicalVariable> free1 = new HashSet<LogicalVariable>(); OperatorPropertiesUtil.getFreeVariablesInSelfOrDesc(op1, free1); if (!free1.isEmpty()) { OperatorManipulationUtil.ntsToEts(op2Ref, context); NestedTupleSourceOperator nts = new NestedTupleSourceOperator( new MutableObject<ILogicalOperator>(subplan)); Mutable<ILogicalOperator> ntsRef = new MutableObject<ILogicalOperator>(nts); Mutable<ILogicalOperator> innerRef = new MutableObject<ILogicalOperator>(op2); InnerJoinOperator join = new InnerJoinOperator( new MutableObject<ILogicalExpression>(ConstantExpression.TRUE), ntsRef, innerRef); op2Ref.setValue(join); context.computeAndSetTypeEnvironmentForOperator(nts); context.computeAndSetTypeEnvironmentForOperator(join); return true; } } } } opRef1 = op1.getInputs().get(0); } } }