Module org.apache.jena.arq
Package org.apache.jena.sparql.algebra.optimize

Class TransformExtendCombine

java.lang.Object
org.apache.jena.sparql.algebra.TransformCopy
org.apache.jena.sparql.algebra.optimize.TransformExtendCombine
All Implemented Interfaces:
Transform
public class TransformExtendCombine extends TransformCopy
An optimizer that aims to combine multiple extend clauses together.

Since the semantics of extend are such that the expressions are expected to be evaluated in order we can combine extends together. This can make evaluation more efficient because all the assignments are done in a single step though depending on the underlying store this may make little or no difference.

Note that standard algebra construction will cause much of this to happen naturally but sometimes it is useful to apply this as an additional independent transform.