com.metamatrix.query.optimizer.relational.rules
Class RuleAssignOutputElements

java.lang.Object
  com.metamatrix.query.optimizer.relational.rules.RuleAssignOutputElements

All Implemented Interfaces:

OptimizerRule

public final class RuleAssignOutputElements
extends java.lang.Object
implements OptimizerRule

This rule is responsible for assigning the output elements to every node in the plan. The output elements define the columns that are returned from every node. This is generally done by figuring out top-down all the elements required to execute the operation at each node and making sure those elements are selected from the children nodes.

Constructor Summary

RuleAssignOutputElements()

Method Summary

PlanNode	execute(PlanNode plan, QueryMetadataInterface metadata, CapabilitiesFinder capFinder, RuleStack rules, AnalysisRecord analysisRecord, CommandContext context) Execute the rule.
java.lang.String	toString() Get name of the rule

Methods inherited from class java.lang.Object

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

Constructor Detail

RuleAssignOutputElements

public RuleAssignOutputElements()

Method Detail

execute

public PlanNode execute(PlanNode plan,
                        QueryMetadataInterface metadata,
                        CapabilitiesFinder capFinder,
                        RuleStack rules,
                        AnalysisRecord analysisRecord,
                        CommandContext context)
                 throws QueryPlannerException,
                        QueryMetadataException,
                        MetaMatrixComponentException

Execute the rule. This rule is executed exactly once during every planning call. The plan is modified in place - only properties are manipulated, structure is unchanged.

Specified by:

execute in interface OptimizerRule

Parameters:

plan - The plan to execute rule on

metadata - The metadata interface

rules - The rule stack, not modified

Returns:

The updated plan

Throws:

QueryPlannerException

QueryMetadataException

MetaMatrixComponentException

toString

public java.lang.String toString()

Get name of the rule

Overrides:

toString in class java.lang.Object

Returns:

Name of the rule