Module org.apache.jena.arq
Class TransformFilterPlacementConservative
java.lang.Object
org.apache.jena.sparql.algebra.TransformCopy
org.apache.jena.sparql.algebra.optimize.TransformFilterPlacementConservative
- All Implemented Interfaces:
Transform
Rewrite an algebra expression to put filters as close to their bound
variables in a BGP. Works on (filter (BGP ...) )
This is a conservative and relatively limited optimization and has been
superseded in the default optimizer by the TransformFilterPlacement
as of the 2.11.x releases. This original version of TransformFilterPlacement
only operates on filters over BGPs, quad blocks, sequences and conditions
(a form of LeftJoin with no scope issues) of the same.
However in some cases it may be desirable to have
the more limited and conservative behaviour so this is preserved in the code
for those who want to use this.
The context flag ARQ.optFilterPlacementConservative
may be set to
have the default optimizer use this in place of the newer and more aggressive
TransformFilterPlacement
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Field Summary
Fields inherited from class org.apache.jena.sparql.algebra.TransformCopy
COPY_ALWAYS, COPY_ONLY_ON_CHANGE
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Constructor Summary
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Method Summary
Methods inherited from class org.apache.jena.sparql.algebra.TransformCopy
transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform, transform
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Constructor Details
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TransformFilterPlacementConservative
public TransformFilterPlacementConservative()
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Method Details
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transform
- Specified by:
transform
in interfaceTransform
- Overrides:
transform
in classTransformCopy
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