/*
* ModeShape (http://www.modeshape.org)
*
* 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 at
*
* 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 org.modeshape.jcr.query.optimize;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.jcr.query.qom.Comparison;
import javax.jcr.query.qom.Constraint;
import javax.jcr.query.qom.DynamicOperand;
import javax.jcr.query.qom.JoinCondition;
import javax.jcr.query.qom.PropertyValue;
import javax.jcr.query.qom.StaticOperand;
import org.modeshape.common.annotation.Immutable;
import org.modeshape.jcr.api.query.qom.SetCriteria;
import org.modeshape.jcr.query.QueryContext;
import org.modeshape.jcr.query.engine.IndexPlan;
import org.modeshape.jcr.query.engine.IndexPlanners;
import org.modeshape.jcr.query.model.Literal;
import org.modeshape.jcr.query.model.SelectorName;
import org.modeshape.jcr.query.plan.PlanNode;
import org.modeshape.jcr.query.plan.PlanNode.Operation;
import org.modeshape.jcr.query.plan.PlanNode.Property;
import org.modeshape.jcr.query.plan.PlanNode.Type;
import org.modeshape.jcr.spi.index.IndexCostCalculator;
import org.modeshape.jcr.spi.index.provider.IndexPlanner;
import org.modeshape.jcr.value.StringFactory;
/**
* A rule that adds indexes below {@link Type#SOURCE} nodes. The rule uses an {@link IndexPlanner} that will actually look at the
* AND-ed constraints for the source (that is, the constraints in the {@link Type#SELECT} above the {@link Type#SOURCE} node but
* below an {@link Type#ACCESS} node) and produce 0 or more indexes. These indexes are then added as {@link Type#INDEX} nodes
* below the {@link Type#SOURCE} node.
*
* @author Randall Hauch (rhauch@redhat.com)
*/
@Immutable
public class AddIndexes implements OptimizerRule {
private static final AddIndexes IMPLICIT_INDEXES = new AddIndexes(null);
/**
* The instance of the rule that uses the implicit indexes, like those for finding nodes (or children or descendants) based
* upon a path.
*
* @return the rule; never null
*/
public static AddIndexes implicitIndexes() {
return IMPLICIT_INDEXES;
}
/**
* The instance of the rule that uses the supplied index planner.
*
* @param planners the index planners; should not be null
* @return the new rule; never null
*/
public static AddIndexes with( IndexPlanners planners ) {
return new AddIndexes(planners);
}
private final IndexPlanners planners;
protected AddIndexes( IndexPlanners planner ) {
this.planners = planner != null ? planner : IndexPlanners.implicit();
}
@Override
public PlanNode execute( final QueryContext context,
PlanNode plan,
LinkedList<OptimizerRule> ruleStack ) {
for (final PlanNode source : plan.findAllAtOrBelow(Type.SOURCE)) {
// There were some constraints, so prepare to collect indexes ...
assert source.getSelectors().size() == 1;
final SelectorName selectorName = source.getSelectors().iterator().next();
// Look for any SELECT nodes above this but below an ACCESS node, because all of the SELECT define
// criteria that are all ANDed together ...
final List<Constraint> constraints = new LinkedList<>();
final List<JoinCondition> joinConditions = new LinkedList<>();
final Set<String> nodeTypeNames = new HashSet<>();
source.applyToAncestors(new Operation() {
@Override
public void apply( PlanNode node ) {
if (node.getType() == Type.SELECT) {
Constraint constraint = node.getProperty(Property.SELECT_CRITERIA, Constraint.class);
if (constraint != null) {
constraints.add(constraint);
// While we're at it, look for the constraint on the primary type. This tells us which node type
// we're working with ...
if (nodeTypeNames.isEmpty()) {
if (constraint instanceof Comparison) {
Comparison comparison = (Comparison)constraint;
if (isPrimaryTypeConstraint(comparison.getOperand1())) {
addLiteral(comparison.getOperand2(), nodeTypeNames);
}
} else if (constraint instanceof SetCriteria) {
SetCriteria criteria = (SetCriteria)constraint;
if (isPrimaryTypeConstraint(criteria.getOperand())) {
// Look for literal values and collect them as the node type names ...
for (StaticOperand operand : criteria.getValues()) {
addLiteral(operand, nodeTypeNames);
}
}
}
}
}
} else if (node.getType() == Type.JOIN) {
// Also look at the join conditions ...
JoinCondition joinCondition = node.getProperty(Property.JOIN_CONDITION, JoinCondition.class);
if (joinCondition != null) {
joinConditions.add(joinCondition);
}
// Look for additional constraints pushed down to the join ...
List<Constraint> joinConstraints = node.getPropertyAsList(Property.JOIN_CONSTRAINTS, Constraint.class);
if (joinConstraints != null) {
for (Constraint joinConstraint : joinConstraints) {
constraints.add(joinConstraint);
}
}
}
}
private boolean isPrimaryTypeConstraint( DynamicOperand operand ) {
if (operand instanceof PropertyValue) {
PropertyValue propValue = (PropertyValue)operand;
if (propValue.getSelectorName().equals(selectorName.getString())) {
// The property value matches our selector name, so this might be a constraint on the
// primary type or mixin types. If so, then the selector name is an alias ...
String propName = propValue.getPropertyName();
return "jcr:primaryType".equals(propName) || "jcr:mixinTypes".equals(propName);
}
}
return false;
}
private void addLiteral( StaticOperand operand,
Set<String> collector ) {
if (operand instanceof Literal) {
// Get the literal value, which should be a node type ...
Literal literal = (Literal)operand;
StringFactory strings = context.getExecutionContext().getValueFactories().getStringFactory();
nodeTypeNames.add(strings.create(literal.value()));
}
}
});
if (!constraints.isEmpty() || !joinConditions.isEmpty()) {
// Get the selector name. The plan's selectors will contain an alias if one is used, so we have to find
// the 'selector.[jcr:primaryType] = '<nodeType>' constraint
// Add the alias ...
nodeTypeNames.add(selectorName.getString());
final List<IndexPlan> indexPlans = new LinkedList<>();
IndexCostCalculator calculator = new IndexCostCalculator() {
@Override
public Set<String> selectedNodeTypes() {
return nodeTypeNames;
}
@Override
public Collection<Constraint> andedConstraints() {
return constraints;
}
@Override
public Collection<JoinCondition> joinConditions() {
return joinConditions;
}
@Override
public Map<String, Object> getVariables() {
return context.getVariables();
}
@Override
public void addIndex( String name,
String workspaceName,
String providerName,
Collection<JoinCondition> joinConditions,
int costEstimate,
long cardinalityEstimate ) {
IndexPlan indexPlan = new IndexPlan(name, workspaceName, providerName, null, joinConditions,
costEstimate, cardinalityEstimate, 1.0f, null);
indexPlans.add(indexPlan);
}
@Override
public void addIndex( String name,
String workspaceName,
String providerName,
Collection<Constraint> constraints,
int costEstimate,
long cardinalityEstimate,
Float selectivityEstimate,
Map<String, Object> parameters ) {
// Add a plan node for this index ...
IndexPlan indexPlan = new IndexPlan(name, workspaceName, providerName, constraints, null, costEstimate,
cardinalityEstimate, selectivityEstimate, parameters);
indexPlans.add(indexPlan);
}
@Override
public void addIndex( String name,
String workspaceName,
String providerName,
Collection<Constraint> constraints,
int costEstimate,
long cardinalityEstimate,
Float selectivityEstimate ) {
addIndex(name, workspaceName, providerName, constraints, costEstimate, cardinalityEstimate,
selectivityEstimate, null);
}
@Override
public void addIndex( String name,
String workspaceName,
String providerName,
Collection<Constraint> constraints,
int costEstimate,
long cardinalityEstimate,
Float selectivityEstimate,
String parameterName,
Object parameterValue ) {
Map<String, Object> params = Collections.singletonMap(parameterName, parameterValue);
addIndex(name, workspaceName, providerName, constraints, costEstimate, cardinalityEstimate,
selectivityEstimate, params);
}
@Override
public void addIndex( String name,
String workspaceName,
String providerName,
Collection<Constraint> constraints,
int costEstimate,
long cardinalityEstimate,
Float selectivityEstimate,
String parameterName1,
Object parameterValue1,
String parameterName2,
Object parameterValue2 ) {
Map<String, Object> params = new HashMap<>();
params.put(parameterName1, parameterValue1);
params.put(parameterName2, parameterValue2);
addIndex(name, workspaceName, providerName, constraints, costEstimate, cardinalityEstimate,
selectivityEstimate, params);
}
};
// And collect the indexes from the index planner ...
planners.applyIndexes(context, calculator);
if (!indexPlans.isEmpty()) {
// Sort the index plans, so the best one is first ...
Collections.sort(indexPlans);
// Add an index node for each index ...
for (IndexPlan indexPlan : indexPlans) {
// Add a plan node for this index ...
PlanNode indexNode = new PlanNode(Type.INDEX, source.getSelectors());
indexNode.setProperty(Property.INDEX_SPECIFICATION, indexPlan);
// and add it under the SOURCE node ...
source.addLastChild(indexNode);
}
}
}
}
return plan;
}
}