org.tribuo.util.tokens.impl

Class ShapeTokenizer

java.lang.Object

org.tribuo.util.tokens.impl.ShapeTokenizer

All Implemented Interfaces:

com.oracle.labs.mlrg.olcut.config.Configurable, com.oracle.labs.mlrg.olcut.provenance.Provenancable<com.oracle.labs.mlrg.olcut.provenance.ConfiguredObjectProvenance>, Cloneable, Tokenizer

public class ShapeTokenizer
extends Object
implements Tokenizer

This tokenizer is loosely based on the notion of word shape which is a common feature used in NLP. The idea here is that continuous runs of letters in the same character class will be grouped together. White space characters are used as delimiters. The character classes are: uppercase letters, lowercase letters, digits, and everything else goes into its own character class. So, for example, "1234abcd" would be split into "1234" and "abcd". And "!@#$" would result in four tokens. Please see unit tests.

Strings are split according to whitespace and contiguous runs of characters in the same character classes. Except for one exception - if uppercase letters are immediately followed by lowercase letters, then we keep them together. This has the effect of recognizing camel case and splits "CamelCase" into "Camel" and "Case". It also splits "ABCdef AAbb" into "ABCdef" and "AAbb".

Constructor Summary

Constructors

Constructor and Description
ShapeTokenizer()

Method Summary

Modifier and Type	Method and Description
boolean	advance() Advances the tokenizer to the next token.
ShapeTokenizer	clone() Clones a tokenizer with it's configuration.
int	getEnd() Gets the ending offset (exclusive) of the current token in the character sequence
com.oracle.labs.mlrg.olcut.provenance.ConfiguredObjectProvenance	getProvenance()
int	getStart() Gets the starting character offset of the current token in the character sequence
String	getText() Gets the text of the current token, as a string
Token.TokenType	getType() Gets the type of the current token.
void	reset(CharSequence cs) Resets the tokenizer so that it operates on a new sequence of characters.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.tribuo.util.tokens.Tokenizer

createSupplier, createThreadLocal, getToken, split, tokenize

Methods inherited from interface com.oracle.labs.mlrg.olcut.config.Configurable

postConfig

Constructor Detail

ShapeTokenizer

public ShapeTokenizer()

Method Detail

getProvenance

public com.oracle.labs.mlrg.olcut.provenance.ConfiguredObjectProvenance getProvenance()

Specified by:

getProvenance in interface com.oracle.labs.mlrg.olcut.provenance.Provenancable<com.oracle.labs.mlrg.olcut.provenance.ConfiguredObjectProvenance>

reset

public void reset(CharSequence cs)

Description copied from interface: Tokenizer

Resets the tokenizer so that it operates on a new sequence of characters.

Specified by:

reset in interface Tokenizer

Parameters:

cs - a character sequence to tokenize

advance

public boolean advance()

Description copied from interface: Tokenizer

Advances the tokenizer to the next token.

Specified by:

advance in interface Tokenizer

Returns:

true if there is such a token, false otherwise.

getText

public String getText()

Description copied from interface: Tokenizer

Gets the text of the current token, as a string

Specified by:

getText in interface Tokenizer

Returns:

the text of the current token

getStart

public int getStart()

Description copied from interface: Tokenizer

Gets the starting character offset of the current token in the character sequence

Specified by:

getStart in interface Tokenizer

Returns:

the starting character offset of the token

getEnd

public int getEnd()

Description copied from interface: Tokenizer

Gets the ending offset (exclusive) of the current token in the character sequence

Specified by:

getEnd in interface Tokenizer

Returns:

the exclusive ending character offset for the current token.

getType

public Token.TokenType getType()

Description copied from interface: Tokenizer

Gets the type of the current token.

Specified by:

getType in interface Tokenizer

Returns:

the type of the current token.

clone

public ShapeTokenizer clone()

Description copied from interface: Tokenizer

Clones a tokenizer with it's configuration. Cloned tokenizers are not processing the same text as the original tokenizer and need to be reset with a fresh CharSequence.

Specified by:

clone in interface Tokenizer

Overrides:

clone in class Object

Returns:

A tokenizer with the same configuration, but independent state.