com.jalios.jcms.search
Class NGramFingerPrint

java.lang.Object
  java.util.Dictionary<K,V>
      java.util.Hashtable<String,Integer>
          com.jalios.jcms.search.NGramFingerPrint

All Implemented Interfaces:

Serializable, Cloneable, Map<String,Integer>

public class NGramFingerPrint
extends Hashtable<String,Integer>

A FingerPrint maps so called NGrams to their number of occurences in the corresponding text. It is able to categorize itself by comparing its FingerPrint with the FingerPrints of a collection of categories. See sdair-94-bc.pdf in the doc direcory of the jar-file for more information.

See Also:

Serialized Form

Constructor Summary

NGramFingerPrint()

Method Summary

Map<String,Integer>	categorize(Collection<NGramFingerPrint> categories) categorizes the FingerPrint by computing the distance to the FingerPrints in the passed Collection.
void	create(String text) fills the FingerPrint with all the NGrams and their numer of occurences in the passed text.
String	getCategory() returns the category of the FingerPrint or "unknown" if the FingerPrint wasn't categorized yet.
Map<String,Integer>	getCategoryDistances()
int	getPosition(String key) gets the position of the NGram passed to method in the FingerPrint.
void	load(String ngram)
protected void	setCategory(String category) sets the category of the FingerPrint
String	toString() returns the FingerPrint as a String in the FingerPrint file-format

Methods inherited from class java.util.Hashtable

clear, clone, contains, containsKey, containsValue, elements, entrySet, equals, get, hashCode, isEmpty, keys, keySet, put, putAll, rehash, remove, size, values

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

NGramFingerPrint

public NGramFingerPrint()

Method Detail

load

public void load(String ngram)

create

public void create(String text)

fills the FingerPrint with all the NGrams and their numer of occurences in the passed text.

Parameters:

text - text to be analysed

categorize

public Map<String,Integer> categorize(Collection<NGramFingerPrint> categories)

categorizes the FingerPrint by computing the distance to the FingerPrints in the passed Collection. the category of the FingerPrint with the lowest distance is assigned to this FingerPrint.

Parameters:

categories -

getCategoryDistances

public Map<String,Integer> getCategoryDistances()

getPosition

public int getPosition(String key)

gets the position of the NGram passed to method in the FingerPrint. the NGrams are in descending order according to the number of occurences in the text which was used creating the FingerPrint.

Parameters:

key - the NGram

Returns:

the position of the NGram in the FingerPrint

getCategory

public String getCategory()

returns the category of the FingerPrint or "unknown" if the FingerPrint wasn't categorized yet.

Returns:

the category of the FingerPrint

toString

public String toString()

returns the FingerPrint as a String in the FingerPrint file-format

Overrides:

toString in class Hashtable<String,Integer>

setCategory

protected void setCategory(String category)

sets the category of the FingerPrint

Parameters:

category - the category