lp.trans
Class Grounder<P>

java.lang.Object
  lp.trans.Grounder<P>

Direct Known Subclasses:

DlpGrounder, LpGrounder

public abstract class Grounder<P>
extends Object

An abstract class that contains common functionality of classes used to ground logic programs (LpGrounder and DlpGrounder).

Version:

1.0.0

Author:

Martin Slota

See Also:

LpGrounder, DlpGrounder

Field Summary

private LparseWrapper	lw An LparseWrapper instance used to execute lparse when grounding the logic program with tagged rules created from the original (non-ground) dynamic logic program.
private List<GrounderMessage>	warnings A list of warnings that lparse issued on the input program.

Constructor Summary

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

Method Summary

List<GrounderMessage>	getWarnings() Returns a list of warnings that lparse issued on the input DLP.
P	ground(P inputProgram) Returns a grounded version of inputProgram.
protected abstract GrounderMessage	makeGrounderMessage(LparseMessage lparseMessage, P inputProgram) Creates an error message based on lparseMessage from lparse and the input program.
protected abstract P	parseOutput(String lparseOutput) Parses the given lparse output and returns the grounded program.
protected abstract void	printProgram(P 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).
void	setLparsePath(String lparsePath) Sets the path to lparse binary that is used to invoke lparse.

Methods inherited from class java.lang.Object

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

Field Detail

lw

private final LparseWrapper lw

An LparseWrapper instance used to execute lparse when grounding the logic program with tagged rules created from the original (non-ground) dynamic logic program. It also parses the standard error output of lparse and translates it into LparseMessage objects.

warnings

private final List<GrounderMessage> warnings

A list of warnings that lparse issued on the input program.

Constructor Detail

Grounder

public Grounder(LparseWrapper wrapper)

Creates a new instance of Grounder 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

setLparsePath

public void setLparsePath(String lparsePath)

Sets the path to lparse binary that is used to invoke lparse.

Parameters:

lparsePath - path to the lparse binary

Throws:

IllegalArgumentException - if lparsePath is null or an empty string

ground

public P ground(P inputProgram)

Returns a grounded version of inputProgram.

Parameters:

inputProgram - the program to ground

Returns:

the grounded version of inputProgram. If inputProgram is null, null is returned.

Throws:

WrapperException - if an error occurs while calling lparse, see LparseWrapper.waitFor()

GrounderMessage - if lparse refuses to ground the input program, usually this means that it cannot guarantee that the resulting grounded program will be finite

IOException - (wrapped in an ExceptionAdapter) if an I/O error occurs while manipulating the standard input and output streams of an lparse process

LpParserException - if this exception is thrown, it is most probably a bug in implementation of this class

getWarnings

public List<GrounderMessage> getWarnings()

Returns a list of warnings that lparse issued on the input DLP. The warnings are in the same order as they were on its standard error output.

Returns:

as specified above

printProgram

protected abstract void printProgram(P 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).

Parameters:

inputProgram - the (ungrounded) input program

writer - a Writer to write to

Throws:

IOException - (wrapped in an ExceptionAdapter) if an I/O error occurs while manipulating the standard input and output streams of an lparse process

makeGrounderMessage

protected abstract GrounderMessage makeGrounderMessage(LparseMessage lparseMessage,
                                                       P inputProgram)

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

Parameters:

lparseMessage - 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 abstract P parseOutput(String lparseOutput)

Parses the given lparse output and returns the grounded program.

Parameters:

lparseOutput - the lparse output

Returns:

the grounded program

Throws:

LpParserException - if this exception is thrown, it is most probably a bug in implementation of this class