/*******************************************************************************
* Copyright (c) 2004, 2007 IBM Corporation and Cambridge Semantics Incorporated.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* File: $Source: /cvsroot/slrp/glitter/com.ibm.adtech.glitter/src/com/ibm/adtech/glitter/query/planning/Attic/OdoQueryOptimizer.java,v $
* Created by: Matthew Roy ( <a href="mailto:mroy@us.ibm.com">mroy@us.ibm.com </a>)
* Created on: Feb 8, 2007
* Revision: $Id: QueryOptimizer.java 229 2007-08-07 15:22:00Z mroy $
*
* Contributors:
* IBM Corporation - initial API and implementation
* Cambridge Semantics Incorporated - Fork to Anzo
*******************************************************************************/
package org.openanzo.glitter.query.planning;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.SortedSet;
import java.util.TreeSet;
import org.openanzo.glitter.query.QueryExecutionPlan;
import org.openanzo.glitter.syntax.abstrakt.TreeNode;
import org.openanzo.glitter.syntax.abstrakt.TriplePatternNode;
/**
* QueryOptimizer
*
* @author Matthew Roy ( <a href="mailto:mroy@cambridgesemantics.com">mroy@cambridgesemantics.com </a>)
*
*/
public class QueryOptimizer implements QueryExecutionPlan {
private final GreedyCostBasedExecutionPlan plan = new GreedyCostBasedExecutionPlan(new SimpleCostModel());
public List<TreeNode> orderNodes(List<? extends TreeNode> nodes) {
TripleList list = new TripleList();
boolean allTPN = true;
List<TreeNode> ntNodes = new ArrayList<TreeNode>();
for (TreeNode node : nodes) {
if (!(node instanceof TriplePatternNode)) {
allTPN = false;
} else {
list.add((TriplePatternNode) node);
}
ntNodes.add(node);
}
if (allTPN) {
ArrayList<TreeNode> tnodes = new ArrayList<TreeNode>();
for (TreeNode tn : list) {
tnodes.add(tn);
}
return tnodes;
} else {
return this.plan.orderNodes(ntNodes);
}
}
/**
* Orders the given nodes by number of variables (ascending)
*
* @param nodes
* @return the set of ordered nodes
*/
public Set<TripleNode> getOrderedSet(Iterator<? extends TreeNode> nodes) {
TripleList list = new TripleList();
boolean allTPN = true;
Collection<TreeNode> ntNodes = new ArrayList<TreeNode>();
while (nodes.hasNext()) {
TreeNode node = nodes.next();
if (!(node instanceof TriplePatternNode)) {
allTPN = false;
} else {
list.add((TriplePatternNode) node);
}
ntNodes.add(node);
}
if (allTPN) {
return list.getSet();
} else {
return null;
}
}
private static class TripleList implements Iterable<TreeNode> {
private final SortedSet<TripleNode> sortedSet = new TreeSet<TripleNode>();
private Set<TripleNode> set = this.sortedSet;
private TripleList() {
}
private void add(TriplePatternNode tripleNode) {
TripleNode node = new TripleNode(tripleNode);
this.sortedSet.add(node);
}
// SortedSet contains set of nodes sorted by number of variables
private void compile() {
// NOTE: the matched variables count is the number of variables in a
// triple that will be
// known by the time the query is run.
// Find the match variable values for all triples
Set<TripleNode> compiled = new TreeSet<TripleNode>();
// VariableReferenceCount runningCount = new VariableReferenceCount();
TripleNode ss[] = this.sortedSet.toArray(new TripleNode[0]);
for (int i = 0; i < ss.length; i++) {
TripleNode current = ss[i];
compiled.add(current);
for (int k = i + 1; k < ss.length; k++) {
current.buildMatch(ss[k]);
}
}
this.set = compiled;
}
public Iterator<TreeNode> iterator() {
compile();
Collection<TreeNode> list = new ArrayList<TreeNode>();
for (TripleNode node : this.set) {
list.add(node.getTriple());
}
return list.iterator();
}
Set<TripleNode> getSet() {
compile();
return this.set;
}
}
}