Package com.semedy.reasoner.rewriter

Class SnapshotRewriter

java.lang.Object

com.semedy.reasoner.rewriter.SnapshotRewriter

All Implemented Interfaces:

Rewriter

public class SnapshotRewriter
extends Object
implements Rewriter

This rewriter changes rules and queries such that facts which should be deleted are excluded from reasoning
E.g. given the rule p(?X) :- q(?X),r(?X).
Facts which should be deleted from q are q(a), q(b).
The deleted facts are stored in the input edb in _delete_q:
_delete_q(a), _delete_q(b)
The rule is now rewritten into: p(?X) :- q(?X),!_delete_q(?X),r(?X).
This is used for snapshot transactions. The last edb is used for the delete predicates

Author:

angele

Constructor Summary

Constructors

Constructor	Description
SnapshotRewriter()

Method Summary

Modifier and Type	Method	Description
String	getDescription()	get a description for the rewriter
String	getName()	get the name of a rewriter
boolean	readsSymbolTable()	indicates whether rewriter has to read the symbol table
IntensionalDB	rewrite(IntensionalDB idb, ExtensionalDB[] edbs, SymbolTable symbolTable, ExternalDataTypeProvider datatypes, Configuration config)	applies the rewriter to a set of rules
void	setBuiltinProvider(BuiltinProvider builtinProvider)	sets the built-in provider for the rewriter
void	setProperties(Properties prp)	set properties
void	setStatistics(SystemMonitor _statistics)	adds a system monitor which has run time data about rules.
boolean	writesSymbolTable()	indicates whether rewriter modifies the symbol table

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

SnapshotRewriter

public SnapshotRewriter()

Method Details

getName

public String getName()

Description copied from interface: Rewriter

get the name of a rewriter

Specified by:

getName in interface Rewriter

Returns:

getDescription

public String getDescription()

Description copied from interface: Rewriter

get a description for the rewriter

Specified by:

getDescription in interface Rewriter

Returns:

readsSymbolTable

public boolean readsSymbolTable()

Description copied from interface: Rewriter

indicates whether rewriter has to read the symbol table

Specified by:

readsSymbolTable in interface Rewriter

Returns:

writesSymbolTable

public boolean writesSymbolTable()

Description copied from interface: Rewriter

indicates whether rewriter modifies the symbol table

Specified by:

writesSymbolTable in interface Rewriter

Returns:

setBuiltinProvider

public void setBuiltinProvider(BuiltinProvider builtinProvider)

Description copied from interface: Rewriter

sets the built-in provider for the rewriter

Specified by:

setBuiltinProvider in interface Rewriter

rewrite

public IntensionalDB rewrite(IntensionalDB idb,
 ExtensionalDB[] edbs,
 SymbolTable symbolTable,
 ExternalDataTypeProvider datatypes,
 Configuration config)
                      throws RewriterException,
IOException

Description copied from interface: Rewriter

applies the rewriter to a set of rules

Specified by:

rewrite in interface Rewriter

Parameters:

idb - , intensional database

edbs - , extensional databases, the last one is used for snapshot transaction data

symbolTable - , symbol table

datatypes - , the external datatypes

config - , configuration

Returns:

Throws:

RewriterException

IOException

setStatistics

public void setStatistics(SystemMonitor _statistics)

Description copied from interface: Rewriter

adds a system monitor which has run time data about rules.

Specified by:

setStatistics in interface Rewriter

setProperties

public void setProperties(Properties prp)

Description copied from interface: Rewriter

set properties

Specified by:

setProperties in interface Rewriter