com.bigdata.rdf.sparql.ast.optimizers

Class ASTWildcardProjectionOptimizer

java.lang.Object

com.bigdata.rdf.sparql.ast.optimizers.ASTWildcardProjectionOptimizer

All Implemented Interfaces:

IASTOptimizer

public class ASTWildcardProjectionOptimizer
extends Object
implements IASTOptimizer

Rewrites any ProjectionNode with a wild card into the set of variables visible to the QueryBase having that projection. This is done first for the NamedSubqueriesNode and then depth-first for the WHERE clause. Only variables projected by a subquery will be projected by the parent query.

Author:

Bryan Thompson

Constructor Summary

Constructors

Constructor and Description
ASTWildcardProjectionOptimizer()

Method Summary

Methods

Modifier and Type	Method and Description
QueryNodeWithBindingSet	optimize(AST2BOpContext context, QueryNodeWithBindingSet input) Optimize the AST.

Methods inherited from class java.lang.Object

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

Constructor Detail

ASTWildcardProjectionOptimizer

public ASTWildcardProjectionOptimizer()

Method Detail

optimize

public QueryNodeWithBindingSet optimize(AST2BOpContext context,
                               QueryNodeWithBindingSet input)

Description copied from interface: IASTOptimizer

Optimize the AST.

Specified by:

optimize in interface IASTOptimizer

Parameters:

context - The evaluation context.

input - The input to the optimizer, consisting of a queryNode and input binding set.

Returns:

An instance of type QueryNodeWithBindingSet.