Package com.onwbp.adaptation

Interface PrefilteredAdaptationFilter

All Superinterfaces:
AdaptationFilter
All Known Implementing Classes:
AbstractPrefilteredAdaptationFilter
public interface PrefilteredAdaptationFilter extends AdaptationFilter
Defines an AdaptationFilter that can be optimized using a prefilter predicate.

A prefilter is an XPath filter used by the query framework to filter records without the need of calling AdaptationFilter.accept(Adaptation). This allows to avoid evaluating the programmatic filter by using, e.g., index scans.

See Also:

  • Method Details

    • getPrefilter

      XPathFilter getPrefilter()
      Defines the prefilter. This method must always return the same filter for an instance of this interface.

      The prefilter

      • must be consistent with AdaptationFilter.accept(Adaptation), i.e., it must evaluate to true for all records where the accept method returns true.
      • may not use parameters.
      • should be selective, i.e., it should evaluate to true only for a relatively small part of the records of the table where the filter is applied on.
      • should be "index-friendly" for best performance, i.e., it should be evaluated using indexes only. This can be checked by activating the debug level of the request log and executing a the request that uses the AdaptationFilter (see Request.setSpecificFilter(AdaptationFilter)). The logged physical plan should have a Lucene scan operation with a filter corresponding to the specified prefilter.

    • create

      static PrefilteredAdaptationFilter create(XPathFilter prefilter, AdaptationFilter filter)
      Creates a PrefilteredAdaptationFilter based on AbstractPrefilteredAdaptationFilter.