edu.stanford.nlp.trees.international.pennchinese

Class CharacterLevelTagExtender

java.lang.Object

edu.stanford.nlp.trees.TreeNormalizer

edu.stanford.nlp.trees.BobChrisTreeNormalizer

edu.stanford.nlp.trees.international.pennchinese.CharacterLevelTagExtender

All Implemented Interfaces:

TreeTransformer, java.io.Serializable, java.util.function.Function<Tree,Tree>

public class CharacterLevelTagExtender
extends BobChrisTreeNormalizer
implements TreeTransformer

A transformer to extend tags down to the level of individual characters. Each word preterminal is split into new preterminals for each character with tags corresponding to the original preterminal tag plus a suffix depending on the position of the character in the word: _S for single-char words, _B for first char of multi-char words, _M for middle chars and _E for final chars.
This is used in combining Chinese parsing and word segmentation using the method of Luo '03.
Note: it implements TreeTransformer because we might want to do away with TreeNormalizers in favor of TreeTransformers

Author:

Galen Andrew (galand@cs.stanford.edu) Date: May 13, 2004

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class edu.stanford.nlp.trees.BobChrisTreeNormalizer

BobChrisTreeNormalizer.AOverAFilter, BobChrisTreeNormalizer.EmptyFilter

Field Summary

Fields inherited from class edu.stanford.nlp.trees.BobChrisTreeNormalizer

aOverAFilter, emptyFilter, tlp

Constructor Summary

Constructors

Constructor and Description
CharacterLevelTagExtender()
CharacterLevelTagExtender(TreebankLanguagePack tlp)

Method Summary

Modifier and Type	Method and Description
static void	main(java.lang.String[] args) for testing -- CURRENTLY BROKEN!!!
Tree	normalizeWholeTree(Tree tree, TreeFactory tf) Normalize a whole tree -- one can assume that this is the root.
Tree	transformTree(Tree tree) Does whatever one needs to do to a particular tree.
Tree	untransformTree(Tree tree)

Methods inherited from class edu.stanford.nlp.trees.BobChrisTreeNormalizer

cleanUpLabel, normalizeNonterminal, normalizeTerminal

Methods inherited from class java.lang.Object

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

Methods inherited from interface edu.stanford.nlp.trees.TreeTransformer

apply

Methods inherited from interface java.util.function.Function

andThen, compose, identity

Constructor Detail

CharacterLevelTagExtender

public CharacterLevelTagExtender()

CharacterLevelTagExtender

public CharacterLevelTagExtender(TreebankLanguagePack tlp)

Method Detail

normalizeWholeTree

public Tree normalizeWholeTree(Tree tree,
                               TreeFactory tf)

Description copied from class: BobChrisTreeNormalizer

Normalize a whole tree -- one can assume that this is the root. This implementation deletes empty elements (ones with nonterminal tag label '-NONE-') from the tree, and splices out unary A over A nodes. It assumes that it is not given a null tree, but it may return one if there are no real words.

Overrides:

normalizeWholeTree in class BobChrisTreeNormalizer

Parameters:

tree - The tree to be normalized

tf - the TreeFactory to create new nodes (if needed)

Returns:

The normalized tree. May be null which means to not use this tree at all.

transformTree

public Tree transformTree(Tree tree)

Description copied from interface: TreeTransformer

Does whatever one needs to do to a particular tree. This routine is passed a whole Tree, and could itself work recursively, but the canonical usage is to invoke this method via the Tree.transform() method, which will apply the transformer in a bottom-up manner to each local Tree, and hence the implementation of TreeTransformer should merely examine and change a local (one-level) Tree.

Specified by:

transformTree in interface TreeTransformer

Overrides:

transformTree in class BobChrisTreeNormalizer

Parameters:

tree - A tree. Classes implementing this interface can assume that the tree passed in is not null.

Returns:

The transformed Tree

untransformTree

public Tree untransformTree(Tree tree)

main

public static void main(java.lang.String[] args)
                 throws java.io.IOException

for testing -- CURRENTLY BROKEN!!!

Parameters:

args - input dir and output filename

Throws:

java.io.IOException