org.modeshape.graph.query.optimize
Class AddAccessNodes

java.lang.Object
  extended by org.modeshape.graph.query.optimize.AddAccessNodes
All Implemented Interfaces:
OptimizerRule

@Immutable
public class AddAccessNodes
extends Object
implements OptimizerRule

An optimizer rule that inserts an ACCESS above each SOURCE leaf node in a query plan. This rule is often the first rule to run against a canonical plan (see RuleBasedOptimizer.populateRuleStack(LinkedList, PlanHints).

Before:

        ...
         |
       SOURCE
 
After:
        ...
         |
       ACCESS
         |
       SOURCE
 


Field Summary
static AddAccessNodes INSTANCE
           
 
Constructor Summary
AddAccessNodes()
           
 
Method Summary
 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 AddAccessNodes INSTANCE
Constructor Detail

AddAccessNodes

public AddAccessNodes()
Method Detail

execute

public PlanNode execute(QueryContext context,
                        PlanNode plan,
                        LinkedList<OptimizerRule> ruleStack)
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
See Also:
OptimizerRule.execute(org.modeshape.graph.query.QueryContext, org.modeshape.graph.query.plan.PlanNode, java.util.LinkedList)

toString

public String toString()

Overrides:
toString in class Object
See Also:
Object.toString()


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