lp.trans
Class DlpGrounder

java.lang.Object
  lp.trans.Grounder<DynamicLogicProgram>
      lp.trans.DlpGrounder

public class DlpGrounder
extends Grounder<DynamicLogicProgram>

Creates a grounded version of a DynamicLogicProgram. This means that the resulting DLP output has the same answer sets as the original DLP and output.isGround() returns true. The transformation is performed using LparseWrapper and can executed by calling the Grounder.ground(Object) method. Lparse warnings (see LparseWrapper.getWarnings()) issued during the grounding process are translated into GrounderMessages and can be retrieved through the Grounder.getWarnings() method.

Version:

1.0.0

Author:

Martin Slota

See Also:

LparseWrapper

Nested Class Summary

private static class	DlpGrounder.DlpDetagger A special parser for parsing the grounded and tagged program.
private static class	DlpGrounder.DlpTagger<W extends Writer> A special LpStructureUnit printer that: gets rid of negation in rule heads by prepending a "p_" or "n_" adds a tagging literal to body of every rule.

Field Summary

private DlpGrounder.DlpDetagger	parser Parses lparse's output and gets rid of the tagging literals again.
private DlpGrounder.DlpTagger<Writer>	printer This printer is used to dump rules in the original dynamic logic program into a single logic program.
private int	programCount Contains the length of the dynamic logic program that is being grounded.

Constructor Summary

DlpGrounder()
Creates a new instance of DlpGrounder that creates its own LparseWrapper instance using its default constructors.

DlpGrounder(LparseWrapper wrapper)
Creates a new instance of DlpGrounder that uses the given object to invoke lparse and process its output.

Method Summary

protected GrounderMessage	makeGrounderMessage(LparseMessage message, DynamicLogicProgram inputProgram) Creates an error message based on lparseMessage from lparse and the input program.
protected DynamicLogicProgram	parseOutput(String program) Parses the given lparse output and returns the grounded program.
protected void	printProgram(DynamicLogicProgram inputProgram, Writer writer) Prints inputProgram in a form that is groundable by lparse (as long as the programmer didn't break the constraints imposed by lparse).

Methods inherited from class lp.trans.Grounder

getWarnings, ground, setLparsePath

Methods inherited from class java.lang.Object

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

Field Detail

programCount

private int programCount

Contains the length of the dynamic logic program that is being grounded. Is needed by parseOutput(String) which doesn't have access to the input program. Therefore, it is set in printProgram(DynamicLogicProgram, Writer).

printer

private final DlpGrounder.DlpTagger<Writer> printer

This printer is used to dump rules in the original dynamic logic program into a single logic program. A literal is added to the body of each rule in order to remember which level of the DLP the rule comes from.

parser

private final DlpGrounder.DlpDetagger parser

Parses lparse's output and gets rid of the tagging literals again.

Constructor Detail

DlpGrounder

public DlpGrounder()

Creates a new instance of DlpGrounder that creates its own LparseWrapper instance using its default constructors.

DlpGrounder

public DlpGrounder(LparseWrapper wrapper)

Creates a new instance of DlpGrounder that uses the given object to invoke lparse and process its output.

Parameters:

wrapper - the object used to execute lparse, parse its warnings and/or errors and create corresponding LparseMessage objects

Method Detail

printProgram

protected void printProgram(DynamicLogicProgram inputProgram,
                            Writer writer)

Prints inputProgram in a form that is groundable by lparse (as long as the programmer didn't break the constraints imposed by lparse).

Specified by:

printProgram in class Grounder<DynamicLogicProgram>

Parameters:

inputProgram - the (ungrounded) input program

writer - a Writer to write to

makeGrounderMessage

protected GrounderMessage makeGrounderMessage(LparseMessage message,
                                              DynamicLogicProgram inputProgram)

Creates an error message based on lparseMessage from lparse and the input program.

Specified by:

makeGrounderMessage in class Grounder<DynamicLogicProgram>

Parameters:

message - the error or warning message issued by lparse

inputProgram - the input program

Returns:

an enhanced message containing a reference to the problematic rule

parseOutput

protected DynamicLogicProgram parseOutput(String program)

Parses the given lparse output and returns the grounded program.

Specified by:

parseOutput in class Grounder<DynamicLogicProgram>

Parameters:

program - the lparse output

Returns:

the grounded program