danbikel.parser.chinese
Class HeadFinder

java.lang.Object
  danbikel.parser.lang.AbstractHeadFinder
      danbikel.parser.chinese.HeadFinder

All Implemented Interfaces:

HeadFinder, Serializable

public class HeadFinder
extends AbstractHeadFinder

A class for determining the head node on the right-hand sides of Chinese parse tree productions.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class danbikel.parser.lang.AbstractHeadFinder

AbstractHeadFinder.HeadFindInstruction

Field Summary

Fields inherited from class danbikel.parser.lang.AbstractHeadFinder

defaultSym, fallbackDefaultHeadTableResource, headFindInstructions, headSuffix, LEFT, leftSym, postHeadSuffix, preHeadSuffix, probRandom, rand, RIGHT, rightSym, useRand, warnDefaultRule

Constructor Summary

HeadFinder()
Constructs an Chinese head-finding object, getting the name of the head table from the value of Settings.get(Settings.headTablePrefix + Language.getLanguage()).

HeadFinder(Sexp headTableSexp)
Constructs an Chinese head-finding object with the specified head table.

Method Summary

int	findHead(Sexp tree, Symbol lhs, SexpList rhs) Finds the head for the grammar production lhs -> rhs.
static void	main(String[] args) A test driver for this class.

Methods inherited from class danbikel.parser.lang.AbstractHeadFinder

addHeadInformation, defaultFindHead, findHead, headSuffix, readHeadTable, scan, scanLeftToRight, scanRightToLeft, tagMatches

Methods inherited from class java.lang.Object

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

Constructor Detail

HeadFinder

public HeadFinder()
           throws IOException,
                  FileNotFoundException

Constructs an Chinese head-finding object, getting the name of the head table from the value of Settings.get(Settings.headTablePrefix + Language.getLanguage()). The named head table is searched for in the locations that are searched by the method Settings.getFileOrResourceAsStream(Class,String).

This constructor will be invoked upon the initialization of the Language class.

Throws:

IOException

FileNotFoundException

See Also:

Settings.getFileOrResourceAsStream(Class, String)

HeadFinder

public HeadFinder(Sexp headTableSexp)

Constructs an Chinese head-finding object with the specified head table.

Method Detail

findHead

public int findHead(Sexp tree,
                    Symbol lhs,
                    SexpList rhs)

Finds the head for the grammar production lhs -> rhs. This method destructively modifies rhs to contain only the canonical version of each of its symbols. This method then calls AbstractHeadFinder.defaultFindHead(Symbol,SexpList), using the canonical version of the lhs symbol for the first argument. If the default head index points to a nonterminal in a coordinating relationship, that is, if the default head index is greater than 2 and the previous nonterminal is a conjunction, then the index returned is the default head index minus 2.

Specified by:

findHead in interface HeadFinder

Specified by:

findHead in class AbstractHeadFinder

Parameters:

tree - the original subtree in which to find the head child, or null if the subtree is not available

lhs - the nonterminal label that is the left-hand side of a grammar production

rhs - a list of symbols that is the right-hand side of a grammar production

Returns:

the 1-based index of the head child in rhs

See Also:

Treebank.isConjunction(Symbol)

main

public static void main(String[] args)

A test driver for this class.