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
Mostra file Open project: paulirwin/lucene.net Class Usage Examples

Protected Properties

Property Type Description
classmap TernaryTree
stoplist List>.Dictionary
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 hyphenatedword ) : void

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 hyphenatedword ) : void
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>.Dictionary

vspace protected_oe property

value space: stores the interletter values
protected ByteVector,org.apache.lucene.analysis.compound.hyphenation vspace
return ByteVector