inpro.irmrsc.simplepcfg
Class Grammar

java.lang.Object
  inpro.irmrsc.simplepcfg.Grammar

public class Grammar
extends java.lang.Object

A simple probabilistic context-free grammar.

Author:

Andreas Peldszus

Field Summary

private java.util.Set<Symbol>	mEliminable
private Symbol	mEnd
private java.util.Map<Symbol,java.util.ArrayList<java.lang.String>>	mExpandsRelation
private java.util.Set<Symbol>	mNonTerminals
private java.util.Map<java.lang.String,Production>	mProductions
private Symbol	mStart
private java.util.Set<Symbol>	mTerminals

Constructor Summary

Grammar()

Method Summary

void	addProduction(java.lang.String id, Production p) adds a new production to the grammar.
void	addProduction(java.lang.String id, Symbol LHS, java.util.List<Symbol> RHS, double Prob) builds a new production and adds it to the grammar.
Symbol	getEnd()
Production	getProduction(java.lang.String id)
java.util.List<java.lang.String>	getProductionsExpandingSymbol(Symbol sym)
Symbol	getStart()
private boolean	hasProductionWithID(java.lang.String id)
void	info()
boolean	isEliminable(Symbol sym)
boolean	isNonTerminalSymbol(Symbol sym)
boolean	isTerminalSymbol(Symbol sym)
void	loadXML(java.net.URL url) loads a grammar from a xml specification provided at the url
void	setStart(Symbol sym)
void	update() recomputes the symbols sets (terminal, nonterminal, and eliminable symbols) and the expand-relation.

Methods inherited from class java.lang.Object

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

Field Detail

mTerminals

private java.util.Set<Symbol> mTerminals

mNonTerminals

private java.util.Set<Symbol> mNonTerminals

mStart

private Symbol mStart

mEnd

private Symbol mEnd

mProductions

private java.util.Map<java.lang.String,Production> mProductions

mExpandsRelation

private java.util.Map<Symbol,java.util.ArrayList<java.lang.String>> mExpandsRelation

mEliminable

private java.util.Set<Symbol> mEliminable

Constructor Detail

Grammar

public Grammar()

Method Detail

addProduction

public void addProduction(java.lang.String id,
                          Symbol LHS,
                          java.util.List<Symbol> RHS,
                          double Prob)

builds a new production and adds it to the grammar. Make sure to update() before using an altered grammar.

addProduction

public void addProduction(java.lang.String id,
                          Production p)

adds a new production to the grammar. Make sure to update() before using an altered grammar.

getStart

public Symbol getStart()

setStart

public void setStart(Symbol sym)

getEnd

public Symbol getEnd()

isTerminalSymbol

public boolean isTerminalSymbol(Symbol sym)

isNonTerminalSymbol

public boolean isNonTerminalSymbol(Symbol sym)

isEliminable

public boolean isEliminable(Symbol sym)

getProductionsExpandingSymbol

public java.util.List<java.lang.String> getProductionsExpandingSymbol(Symbol sym)

Returns:

a list of IDs of Productions expanding the specified symbol

getProduction

public Production getProduction(java.lang.String id)

update

public void update()

recomputes the symbols sets (terminal, nonterminal, and eliminable symbols) and the expand-relation. This is necessary after the grammar was altered, as e.g. by adding a new production. Using an altered but not yet updated grammar will result in unexpected behaviour.

info

public void info()

hasProductionWithID

private boolean hasProductionWithID(java.lang.String id)

loadXML

public void loadXML(java.net.URL url)

loads a grammar from a xml specification provided at the url

Parameters:

url - the specified url of the xml to load