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* 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 static org.teiid.query.analysis.AnalysisRecord.*;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import org.teiid.api.exception.query.ExpressionEvaluationException;
import org.teiid.client.plan.PlanNode;
import org.teiid.common.buffer.BlockedException;
import org.teiid.common.buffer.TupleBatch;
import org.teiid.common.buffer.TupleBuffer;
import org.teiid.core.TeiidComponentException;
import org.teiid.core.TeiidProcessingException;
import org.teiid.query.analysis.AnalysisRecord;
import org.teiid.query.sql.LanguageObject;
import org.teiid.query.sql.symbol.AliasSymbol;
import org.teiid.query.sql.symbol.Expression;
import org.teiid.query.sql.util.SymbolMap;
public class ProjectNode extends SubqueryAwareRelationalNode {
private static final List<?>[] EMPTY_TUPLE = new List[]{Arrays.asList(new Object[] {})};
private List<? extends Expression> selectSymbols;
// Derived element lookup map
private Map<Expression, Integer> elementMap;
private boolean needsProject = true;
private List<Expression> expressions;
private int[] projectionIndexes;
// Saved state when blocked on evaluating a row - must be reset
private TupleBatch currentBatch;
private int currentRow = 1;
protected ProjectNode() {
super();
}
public ProjectNode(int nodeID) {
super(nodeID);
}
public void reset() {
super.reset();
currentBatch = null;
currentRow = 1;
}
/**
* return List of select symbols
* @return List of select symbols
*/
public List<? extends Expression> getSelectSymbols() {
return this.selectSymbols;
}
public void setSelectSymbols(List<? extends Expression> symbols) {
this.selectSymbols = symbols;
elementMap = Collections.emptyMap();
this.projectionIndexes = new int[this.selectSymbols.size()];
Arrays.fill(this.projectionIndexes, -1);
this.expressions = new ArrayList<Expression>(this.selectSymbols.size());
for (Expression ses : this.selectSymbols) {
this.expressions.add(SymbolMap.getExpression(ses));
}
}
@Override
public void addChild(RelationalNode child) {
super.addChild(child);
init();
}
void init() {
List<? extends Expression> childElements = getChildren()[0].getElements();
// Create element lookup map for evaluating project expressions
this.elementMap = createLookupMap(childElements);
// Check whether project needed at all - this occurs if:
// 1. outputMap == null (see previous block)
// 2. project elements are either elements or aggregate symbols (no processing required)
// 3. order of input values == order of output values
needsProject = childElements.size() != selectSymbols.size();
for(int i=0; i<selectSymbols.size(); i++) {
Expression symbol = selectSymbols.get(i);
if(symbol instanceof AliasSymbol) {
Integer index = elementMap.get(symbol);
if(index != null && index.intValue() == i) {
projectionIndexes[i] = index;
continue;
}
symbol = ((AliasSymbol)symbol).getSymbol();
}
Integer index = elementMap.get(symbol);
if(index == null) {
needsProject = true;
} else {
if (index.intValue() != i) {
needsProject = true;
}
projectionIndexes[i] = index;
}
}
}
public TupleBatch nextBatchDirect()
throws BlockedException, TeiidComponentException, TeiidProcessingException {
if(currentBatch == null) {
// There was no saved batch, so get a new one
//in the case of select with no from, should return only
//one batch with one row
if(this.getChildren()[0] == null){
currentBatch = new TupleBatch(1, EMPTY_TUPLE);
currentBatch.setTerminationFlag(true);
}else{
currentBatch = this.getChildren()[0].nextBatch();
}
// Check for no project needed and pass through
if(!needsProject) {
TupleBatch result = currentBatch;
currentBatch = null;
return result;
}
}
while (currentRow <= currentBatch.getEndRow() && !isBatchFull()) {
List<?> tuple = currentBatch.getTuple(currentRow);
List<Object> projectedTuple = new ArrayList<Object>(selectSymbols.size());
// Walk through symbols
for(int i=0; i<expressions.size(); i++) {
Expression symbol = expressions.get(i);
updateTuple(symbol, i, tuple, projectedTuple);
}
// Add to batch
addBatchRow(projectedTuple);
currentRow++;
}
if (currentRow > currentBatch.getEndRow()) {
if(currentBatch.getTerminationFlag()) {
terminateBatches();
}
currentBatch = null;
}
return pullBatch();
}
private void updateTuple(Expression symbol, int projectionIndex, List<?> values, List<Object> tuple)
throws BlockedException, TeiidComponentException, ExpressionEvaluationException {
int index = this.projectionIndexes[projectionIndex];
if(index != -1) {
tuple.add(values.get(index));
} else {
tuple.add(getEvaluator(this.elementMap).evaluate(symbol, values));
}
}
protected void getNodeString(StringBuffer str) {
super.getNodeString(str);
str.append(selectSymbols);
}
public Object clone(){
ProjectNode clonedNode = new ProjectNode();
this.copyTo(clonedNode);
return clonedNode;
}
protected void copyTo(ProjectNode target){
super.copyTo(target);
target.selectSymbols = this.selectSymbols;
target.needsProject = needsProject;
target.elementMap = elementMap;
target.expressions = expressions;
target.projectionIndexes = projectionIndexes;
}
public PlanNode getDescriptionProperties() {
PlanNode props = super.getDescriptionProperties();
AnalysisRecord.addLanaguageObjects(props, PROP_SELECT_COLS, this.selectSymbols);
return props;
}
@Override
public Collection<? extends LanguageObject> getObjects() {
return this.selectSymbols;
}
@Override
public boolean hasBuffer() {
return !needsProject && this.getChildren()[0].hasBuffer();
}
@Override
public TupleBuffer getBufferDirect(int maxRows) throws BlockedException,
TeiidComponentException, TeiidProcessingException {
return this.getChildren()[0].getBuffer(maxRows);
}
}