/*
* JBoss, Home of Professional Open Source.
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership. Some portions may be licensed
* to Red Hat, Inc. under one or more contributor license agreements.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA.
*/
package org.teiid.query.processor.relational;
import java.util.List;
import java.util.Map;
import org.teiid.common.buffer.IndexedTupleSource;
import org.teiid.core.TeiidComponentException;
import org.teiid.core.TeiidProcessingException;
import org.teiid.query.eval.Evaluator;
import org.teiid.query.processor.relational.SourceState.ImplicitBuffer;
import org.teiid.query.sql.lang.JoinType;
import org.teiid.query.sql.symbol.ElementSymbol;
import org.teiid.query.sql.symbol.Expression;
import org.teiid.query.sql.symbol.SingleElementSymbol;
import org.teiid.query.sql.util.SymbolMap;
/**
* Variation of a nested loop join that handles nested tables
*/
public class NestedTableJoinStrategy extends JoinStrategy {
private SymbolMap leftMap;
private SymbolMap rightMap;
private Evaluator eval;
private boolean outerMatched;
@Override
public NestedTableJoinStrategy clone() {
NestedTableJoinStrategy clone = new NestedTableJoinStrategy();
clone.leftMap = leftMap;
clone.rightMap = rightMap;
return clone;
}
@Override
public void initialize(JoinNode joinNode) {
super.initialize(joinNode);
this.eval = new Evaluator(null, joinNode.getDataManager(), joinNode.getContext());
}
public void setLeftMap(SymbolMap leftMap) {
this.leftMap = leftMap;
}
public void setRightMap(SymbolMap rightMap) {
this.rightMap = rightMap;
}
@Override
protected void openLeft() throws TeiidComponentException,
TeiidProcessingException {
if (leftMap == null) {
super.openLeft();
}
}
@Override
protected void openRight() throws TeiidComponentException,
TeiidProcessingException {
if (rightMap == null) {
super.openRight();
this.rightSource.setImplicitBuffer(ImplicitBuffer.FULL);
}
}
@Override
protected void process() throws TeiidComponentException,
TeiidProcessingException {
if (leftMap != null && !leftSource.open) {
for (Map.Entry<ElementSymbol, Expression> entry : leftMap.asMap().entrySet()) {
joinNode.getContext().getVariableContext().setValue(entry.getKey(), eval.evaluate(entry.getValue(), null));
}
leftSource.getSource().reset();
super.openLeft();
}
IndexedTupleSource its = leftSource.getIterator();
while (its.hasNext() || leftSource.getCurrentTuple() != null) {
List<?> leftTuple = leftSource.getCurrentTuple();
if (leftTuple == null) {
leftTuple = leftSource.saveNext();
}
updateContext(leftTuple, leftSource.getSource().getElements());
if (rightMap != null && !rightSource.open) {
for (Map.Entry<ElementSymbol, Expression> entry : rightMap.asMap().entrySet()) {
joinNode.getContext().getVariableContext().setValue(entry.getKey(), eval.evaluate(entry.getValue(), null));
}
rightSource.getSource().reset();
super.openRight();
}
IndexedTupleSource right = rightSource.getIterator();
while (right.hasNext() || rightSource.getCurrentTuple() != null) {
List<?> rightTuple = rightSource.getCurrentTuple();
if (rightTuple == null) {
rightTuple = rightSource.saveNext();
}
List<?> outputTuple = outputTuple(this.leftSource.getCurrentTuple(), this.rightSource.getCurrentTuple());
boolean matches = this.joinNode.matchesCriteria(outputTuple);
rightSource.saveNext();
if (matches) {
outerMatched = true;
joinNode.addBatchRow(outputTuple);
}
}
if (!outerMatched && this.joinNode.getJoinType() == JoinType.JOIN_LEFT_OUTER) {
joinNode.addBatchRow(outputTuple(this.leftSource.getCurrentTuple(), this.rightSource.getOuterVals()));
}
outerMatched = false;
if (rightMap == null) {
rightSource.getIterator().setPosition(1);
} else {
rightSource.close();
for (Map.Entry<ElementSymbol, Expression> entry : rightMap.asMap().entrySet()) {
joinNode.getContext().getVariableContext().remove(entry.getKey());
}
}
leftSource.saveNext();
updateContext(null, leftSource.getSource().getElements());
}
if (leftMap != null) {
leftSource.close();
for (Map.Entry<ElementSymbol, Expression> entry : leftMap.asMap().entrySet()) {
joinNode.getContext().getVariableContext().remove(entry.getKey());
}
}
}
private void updateContext(List<?> tuple,
List<SingleElementSymbol> elements) {
for (int i = 0; i < elements.size(); i++) {
SingleElementSymbol element = elements.get(i);
if (element instanceof ElementSymbol) {
if (tuple == null) {
joinNode.getContext().getVariableContext().remove((ElementSymbol)element);
} else {
joinNode.getContext().getVariableContext().setValue((ElementSymbol)element, tuple.get(i));
}
}
}
}
public String toString() {
return "NESTED TABLE JOIN"; //$NON-NLS-1$
}
}