org.dmd.util.parsing

Class Classifier

java.lang.Object

org.dmd.util.parsing.Classifier

public class Classifier
extends Object

The Classifier class takes an input string, breaks it into tokens and classifies each token as either a basic token type eg. (Token.TEXT, Token.INTEGER, Token.FLOAT) or as a custom token type defined by the user. This approach is especially useful when an entire line of input has to parsed and checked against some allowable format.

See Also:

Token, TokenArrayList

Constructor Summary

Constructors

Constructor and Description
Classifier() Default constructor.
Classifier(Dictionary d) Creates a new classifier that recognizes the tokens specified in the given dictionary.
Classifier(Dictionary d, boolean useDefaults) Creates a new classifier that recognizes the tokens specified in the given dictionary.

Method Summary

Modifier and Type	Method and Description
boolean	addKeyword(String k, int i) Adds a new keyword to the classifier's dictionary.
boolean	addSeparator(String c, int i) Adds a new separator to the classifier.
TokenArrayList	classify(String s, boolean returnSeps) The classify function breaks down the specified string into tokens and passes back an array of classified tokens.

Methods inherited from class java.lang.Object

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

Constructor Detail

Classifier

public Classifier()

Default constructor.

Classifier

public Classifier(Dictionary d)

Creates a new classifier that recognizes the tokens specified in the given dictionary.

Parameters:

d - The dictionary that contains keyword tokens.

Classifier

public Classifier(Dictionary d,
                  boolean useDefaults)

Creates a new classifier that recognizes the tokens specified in the given dictionary.

Parameters:

d - The dictionary that contains keyword tokens.

useDefaults - A flag that indicates whether or not we should use the default delimiter characters ' ', \t \r \n \f when tokenizing a string. If this flag is set to false, you should add your own seperator characters using the addSeperator() method.

Method Detail

addKeyword

public boolean addKeyword(String k,
                          int i)

Adds a new keyword to the classifier's dictionary.

The text should be 2 or more characters in length. If you want to recognize a single character as a token, you should add it using the addSeparator() method.

Parameters:

k - The text to be recognized as a keyword.

i - Its unique numeric identifier.

Returns:

true if the keyword and its identifier are unique and false otherwise.

addSeparator

public boolean addSeparator(String c,
                            int i)

Adds a new separator to the classifier.

Parameters:

c - A string containing a single character to be recognized as a separator.

i - Its unique numeric identifier.

Returns:

true if the separator and its identifier are unique and false otherwise.

classify

public TokenArrayList classify(String s,
                               boolean returnSeps)

The classify function breaks down the specified string into tokens and passes back an array of classified tokens.

Parameters:

s - The string to be parsed.

returnSeps - Set to true if the separators should be returned as tokens.