Interface XPLAINFactoryIF

  • All Known Implementing Classes:
    XPLAINFactory

    public interface XPLAINFactoryIF
    This is the factory interface of the XPLAINFactory facility. It extends the possibilities and provides a convenient protocol to explain queries on basis of the query execution plan. This plan manfifests in Derby in the different ResultSets and their associated statistics. The introduction of this factory interface makes it possible to switch to another implementation or to easily extend the API.
    • Field Summary

      Fields 
      Modifier and Type Field Description
      static java.lang.String MODULE
      Module name for the monitor's module locating system.
    • Field Detail

      • MODULE

        static final java.lang.String MODULE
        Module name for the monitor's module locating system.
        See Also:
        Constant Field Values
    • Method Detail

      • getXPLAINVisitor

        XPLAINVisitor getXPLAINVisitor()
                                throws StandardException
        This method returns an appropriate visitor to traverse the ResultSetStatistics. Depending on the current configuration, the perfect visitor will be chosen, created and cached by this factory method.
        Returns:
        a XPLAINVisitor to traverse the ResultSetStatistics
        Throws:
        StandardException
        See Also:
        XPLAINVisitor
      • freeResources

        void freeResources()
        This method gets called when the user switches off the explain facility. The factory destroys for example the cached visitor implementation(s) or releases resources to save memory.