org.modeshape.jcr.query.optimize

Class ReorderSortAndRemoveDuplicates

java.lang.Object

org.modeshape.jcr.query.optimize.ReorderSortAndRemoveDuplicates

All Implemented Interfaces:

OptimizerRule

@Immutable
public class ReorderSortAndRemoveDuplicates
extends Object
implements OptimizerRule

An optimizer rule that looks for a PlanNode.Type.SORT plan node below a PlanNode.Type.DUP_REMOVE, and swaps them. This ensures that the duplicate removal is always lower in the tree. This is advantageous because many sort algorithms can also efficiently remove duplicates, so it is often better for the PlanNode.Type.SORT plan node to appear higher in the optimized plan.

Field Summary

Fields

Modifier and Type	Field and Description
static ReorderSortAndRemoveDuplicates	INSTANCE

Constructor Summary

Constructors

Constructor and Description
ReorderSortAndRemoveDuplicates()

Method Summary

Modifier and Type	Method and Description
PlanNode	execute(QueryContext context, PlanNode plan, LinkedList<OptimizerRule> ruleStack) Optimize the supplied plan using the supplied context, hints, and yet-to-be-run rules.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

INSTANCE

public static final ReorderSortAndRemoveDuplicates INSTANCE

Constructor Detail

ReorderSortAndRemoveDuplicates

public ReorderSortAndRemoveDuplicates()

Method Detail

execute

public PlanNode execute(QueryContext context,
                        PlanNode plan,
                        LinkedList<OptimizerRule> ruleStack)

Description copied from interface: OptimizerRule

Optimize the supplied plan using the supplied context, hints, and yet-to-be-run rules.

Specified by:

execute in interface OptimizerRule

Parameters:

context - the context in which the query is being optimized; never null

plan - the plan to be optimized; never null

ruleStack - the stack of rules that will be run after this rule; never null

Returns:

the optimized plan; never null

toString

public String toString()

Overrides:

toString in class Object