C# Class org.apache.lucene.analysis.compound.hyphenation.HyphenationTree

This tree structure stores the hyphenation patterns in an efficient way for fast lookup. It provides the provides the method to hyphenate a word. This class has been taken from the Apache FOP project (http://xmlgraphics.apache.org/fop/). They have been slightly modified.

Inheritance: TernaryTree, PatternConsumer

Exibir arquivo Open project: paulirwin/lucene.net Class Usage Examples

Protected Properties

Property	Type	Description
classmap	TernaryTree
stoplist	List
vspace	ByteVector

Public Methods

Method	Description
HyphenationTree ( ) : System
addClass ( string chargroup ) : void	Add a character class to the tree. It is used by PatternParser PatternParser as callback to add character classes. Character classes define the valid word characters for hyphenation. If a word contains a character not defined in any of the classes, it is not hyphenated. It also defines a way to normalize the characters in order to compare them with the stored patterns. Usually pattern files use only lower case characters, in this case a class for letter 'a', for example, should be defined as "aA", the first character being the normalization char.
addException ( string word, List	Add an exception to the tree. It is used by PatternParser PatternParser class as callback to store the hyphenation exceptions.
addPattern ( string pattern, string ivalue ) : void	Add a pattern to the tree. Mainly, to be used by PatternParser PatternParser class as callback to add a pattern to the tree.
findPattern ( string pat ) : string
hyphenate ( char w, int offset, int len, int remainCharCount, int pushCharCount ) : Hyphenation	Hyphenate word and return an array of hyphenation points.
hyphenate ( string word, int remainCharCount, int pushCharCount ) : Hyphenation	Hyphenate word and return a Hyphenation object.
loadPatterns ( File f ) : void	Read hyphenation patterns from an XML file.
loadPatterns ( InputSource source ) : void	Read hyphenation patterns from an XML file.
printStats ( PrintStream @out ) : void

Protected Methods

Method	Description
getValues ( int k ) : sbyte[]
hstrcmp ( char s, int si, char t, int ti ) : int	String compare, returns 0 if equal or t is a substring of s
packValues ( string values ) : int	Packs the values by storing them in 4 bits, two values into a byte Values range is from 0 to 9. We use zero as terminator, so we'll add 1 to the value.
searchPatterns ( char word, int index, sbyte il ) : void	Search for all possible partial matches of word starting at index an update interletter values. In other words, it does something like: `for(i=0; i<patterns.length; i++) { if ( word.substring(index).startsWidth(patterns[i]) ) update_interletter_values(patterns[i]); }` But it is done in an efficient way since the patterns are stored in a ternary tree. In fact, this is the whole purpose of having the tree: doing this search without having to test every single pattern. The number of patterns for languages such as English range from 4000 to 10000. Thus, doing thousands of string comparisons for each word to hyphenate would be really slow without the tree. The tradeoff is memory, but using a ternary tree instead of a trie, almost halves the the memory used by Lout or TeX. It's also faster than using a hash table
unpackValues ( int k ) : string

Method Details

HyphenationTree() public method

public HyphenationTree ( ) : System
return	System

addClass() public method

Add a character class to the tree. It is used by PatternParser PatternParser as callback to add character classes. Character classes define the valid word characters for hyphenation. If a word contains a character not defined in any of the classes, it is not hyphenated. It also defines a way to normalize the characters in order to compare them with the stored patterns. Usually pattern files use only lower case characters, in this case a class for letter 'a', for example, should be defined as "aA", the first character being the normalization char.

public addClass ( string chargroup ) : void
chargroup	string
return	void

addException() public method

Add an exception to the tree. It is used by PatternParser PatternParser class as callback to store the hyphenation exceptions.

public addException ( string word, List
word	string	normalized word
hyphenatedword	List	a vector of alternating strings and /// objects.
return	void

addPattern() public method

Add a pattern to the tree. Mainly, to be used by PatternParser PatternParser class as callback to add a pattern to the tree.

public addPattern ( string pattern, string ivalue ) : void
pattern	string	the hyphenation pattern
ivalue	string	interletter weight values indicating the desirability and /// priority of hyphenating at a given point within the pattern. It /// should contain only digit characters. (i.e. '0' to '9').
return	void

findPattern() public method

public findPattern ( string pat ) : string
pat	string
return	string

getValues() protected method

protected getValues ( int k ) : sbyte[]
k	int
return	sbyte[]

hstrcmp() protected method

String compare, returns 0 if equal or t is a substring of s

protected hstrcmp ( char s, int si, char t, int ti ) : int
s	char
si	int
t	char
ti	int
return	int

hyphenate() public method

Hyphenate word and return an array of hyphenation points.

public hyphenate ( char w, int offset, int len, int remainCharCount, int pushCharCount ) : Hyphenation
w	char	char array that contains the word
offset	int	Offset to first character in word
len	int	Length of word
remainCharCount	int	Minimum number of characters allowed before the /// hyphenation point.
pushCharCount	int	Minimum number of characters allowed after the /// hyphenation point.
return	Hyphenation

hyphenate() public method

Hyphenate word and return a Hyphenation object.

public hyphenate ( string word, int remainCharCount, int pushCharCount ) : Hyphenation
word	string	the word to be hyphenated
remainCharCount	int	Minimum number of characters allowed before the /// hyphenation point.
pushCharCount	int	Minimum number of characters allowed after the /// hyphenation point.
return	Hyphenation

loadPatterns() public method

Read hyphenation patterns from an XML file.

In case the parsing fails

public loadPatterns ( File f ) : void
f	File	the filename
return	void

loadPatterns() public method

Read hyphenation patterns from an XML file.

In case the parsing fails

public loadPatterns ( InputSource source ) : void
source	InputSource	the InputSource for the file
return	void

packValues() protected method

Packs the values by storing them in 4 bits, two values into a byte Values range is from 0 to 9. We use zero as terminator, so we'll add 1 to the value.

protected packValues ( string values ) : int
values	string	a string of digits from '0' to '9' representing the /// interletter values.
return	int

printStats() public method

public printStats ( PrintStream @out ) : void
@out	PrintStream
return	void

searchPatterns() protected method

Search for all possible partial matches of word starting at index an update interletter values. In other words, it does something like:

 for(i=0; i<patterns.length; i++) { if ( word.substring(index).startsWidth(patterns[i]) ) update_interletter_values(patterns[i]); }

But it is done in an efficient way since the patterns are stored in a ternary tree. In fact, this is the whole purpose of having the tree: doing this search without having to test every single pattern. The number of patterns for languages such as English range from 4000 to 10000. Thus, doing thousands of string comparisons for each word to hyphenate would be really slow without the tree. The tradeoff is memory, but using a ternary tree instead of a trie, almost halves the the memory used by Lout or TeX. It's also faster than using a hash table

protected searchPatterns ( char word, int index, sbyte il ) : void
word	char	null terminated word to match
index	int	start index from word
il	sbyte	interletter values array to update
return	void

unpackValues() protected method

protected unpackValues ( int k ) : string
k	int
return	string

Property Details

classmap protected_oe property

This map stores the character classes

protected TernaryTree classmap
return	TernaryTree

stoplist protected_oe property

This map stores hyphenation exceptions

protected Dictionary> stoplist
return	List

vspace protected_oe property

value space: stores the interletter values

protected ByteVector,org.apache.lucene.analysis.compound.hyphenation vspace
return	ByteVector