org.modeshape.jcr.query.optimize

Class RuleBasedOptimizer

java.lang.Object

org.modeshape.jcr.query.optimize.RuleBasedOptimizer

All Implemented Interfaces:

Optimizer

@Immutable
public class RuleBasedOptimizer
extends Object
implements Optimizer

Optimizer implementation that optimizes a query using a stack of rules. Subclasses can override the populateRuleStack(LinkedList, PlanHints) method to define the stack of rules they'd like to use, including the use of custom rules.

Constructor Summary

Constructors

Constructor and Description
RuleBasedOptimizer()

Method Summary

Modifier and Type	Method and Description
PlanNode	optimize(QueryContext context, PlanNode plan) Optimize the supplied query plan and produce an executable processor plan.
protected void	populateIndexingRules(LinkedList<OptimizerRule> ruleStack, PlanHints hints) Method that is used to add the indexing rules to the rule stack.
protected void	populateRuleStack(LinkedList<OptimizerRule> ruleStack, PlanHints hints) Method that is used to create the initial rule stack.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RuleBasedOptimizer

public RuleBasedOptimizer()

Method Detail

optimize

public PlanNode optimize(QueryContext context,
                         PlanNode plan)

Description copied from interface: Optimizer

Optimize the supplied query plan and produce an executable processor plan.

Specified by:

optimize in interface Optimizer

Parameters:

context - the context in which the query is being optimized

plan - the query plan to be optimized

Returns:

the optimized query plan; never null

populateRuleStack

protected void populateRuleStack(LinkedList<OptimizerRule> ruleStack,
                                 PlanHints hints)

Method that is used to create the initial rule stack. This method can be overridden by subclasses

Parameters:

ruleStack - the stack where the rules should be placed; never null

hints - the plan hints

populateIndexingRules

protected void populateIndexingRules(LinkedList<OptimizerRule> ruleStack,
                                     PlanHints hints)

Method that is used to add the indexing rules to the rule stack. This method can be overridden by subclasses when custom indexing rules are to be used. By default, this method simply adds the AddIndexes rule.

Parameters:

ruleStack - the stack where the rules should be placed; never null

hints - the plan hints