Interface XPLAINFactoryIF
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- 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.
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Field Summary
Fields Modifier and Type Field Description static java.lang.String
MODULE
Module name for the monitor's module locating system.
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description void
freeResources()
This method gets called when the user switches off the explain facility.XPLAINVisitor
getXPLAINVisitor()
This method returns an appropriate visitor to traverse the ResultSetStatistics.
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Field Detail
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MODULE
static final java.lang.String MODULE
Module name for the monitor's module locating system.- See Also:
- Constant Field Values
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Method Detail
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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
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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.
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