aima.basic
Class Tokenizer

java.lang.Object
  aima.basic.Tokenizer

All Implemented Interfaces:

java.util.Enumeration

public class Tokenizer
extends java.lang.Object
implements java.util.Enumeration

Replacement for StringTokenizer in java.util, beacuse of bug in the Sun's implementation.

Field Summary

static java.lang.String

DEFAULT_DELIMITERS Default delimiters "\t\n\r\f": the space character, the tab character, the newline character, the carriage-return character, and the form-feed character.

Constructor Summary

Tokenizer(java.lang.String str)
Constructs a string tokenizer for the specified string.

Tokenizer(java.lang.String str, char delim)
Constructs a string tokenizer for the specified string.

Tokenizer(java.lang.String str, java.lang.String delim)
Constructs a string tokenizer for the specified string.

Tokenizer(java.lang.String str, java.lang.String delim, boolean returnTokens)
Constructs a string tokenizer for the specified string.

Method Summary

int	countTokens() Calculates the number of times that this tokenizer's nextToken method can be called before it generates an exception.
boolean	hasMoreElements() Returns the same value as the hasMoreTokens method.
boolean	hasMoreTokens() Tests if there are more tokens available from this tokenizer's string.
java.lang.Object	nextElement() Returns the same value as the nextToken method, except that its declared return value is Object rather than String.
java.lang.String	nextToken() Returns the next token from this string tokenizer.
java.lang.String	nextToken(java.lang.String delim) Returns the next token in this string tokenizer's string.
void	reset() Resets this tokenizer's state so the tokenizing starts from the begin.
static java.lang.String[]	tokenize(java.lang.String str, java.lang.String delim, boolean returnTokens) Constructs a string tokenizer for the specified string.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_DELIMITERS

public static final java.lang.String DEFAULT_DELIMITERS

Default delimiters "\t\n\r\f": the space character, the tab character, the newline character, the carriage-return character, and the form-feed character.

See Also:

Constant Field Values

Constructor Detail

Tokenizer

public Tokenizer(java.lang.String str,
                 java.lang.String delim,
                 boolean returnTokens)

Constructs a string tokenizer for the specified string. All characters in the delim argument are the delimiters for separating tokens. If the returnTokens flag is true, then the delimiter characters are also returned as tokens. Each delimiter is returned as a string of length one. If the flag is false, the delimiter characters are skipped and only serve as separators between tokens.

Parameters:

str - a string to be parsed

delim - the delimiters

returnTokens - flag indicating whether to return the delimiters as tokens

Tokenizer

public Tokenizer(java.lang.String str,
                 java.lang.String delim)

Constructs a string tokenizer for the specified string. The characters in the delim argument are the delimiters for separating tokens. Delimiter characters themselves will not be treated as tokens.

Parameters:

str - a string to be parsed

delim - the delimiters

Tokenizer

public Tokenizer(java.lang.String str,
                 char delim)

Constructs a string tokenizer for the specified string. The character in the delim argument is the delimiter for separating tokens. Delimiter character themselves will not be treated as token.

Parameters:

str - a string to be parsed

delim - the delimiter

Tokenizer

public Tokenizer(java.lang.String str)

Constructs a string tokenizer for the specified string. The tokenizer uses the default delimiter set, which is " \t\n\r\f": the space character, the tab character, the newline character, the carriage-return character, and the form-feed character. Delimiter characters themselves will not be treated as tokens.

Parameters:

str - a string to be parsed

Method Detail

hasMoreTokens

public boolean hasMoreTokens()

Tests if there are more tokens available from this tokenizer's string. If this method returns true, then a subsequent call to nextToken with no argument will successfully return a token.

Returns:

true if and only if there is at least one token in the string after the current position; false otherwise.

nextToken

public java.lang.String nextToken()
                           throws java.util.NoSuchElementException

Returns the next token from this string tokenizer.

Returns:

the next token from this string tokenizer

Throws:

java.util.NoSuchElementException - if there are no more tokens in this tokenizer's string

nextToken

public java.lang.String nextToken(java.lang.String delim)
                           throws java.util.NoSuchElementException

Returns the next token in this string tokenizer's string. First, the set of characters considered to be delimiters by this Tokenizer object is changed to be the characters in the string delim. Then the next token in the string after the current position is returned. The current position is advanced beyond the recognized token. The new delimiter set remains the default after this call.

Parameters:

delim - the new delimiters

Returns:

the next token, after switching to the new delimiter set

Throws:

java.util.NoSuchElementException - if there are no more tokens in this tokenizer's string.

hasMoreElements

public boolean hasMoreElements()

Returns the same value as the hasMoreTokens method. It exists so that this class can implement the Enumeration interface.

Specified by:

hasMoreElements in interface java.util.Enumeration

Returns:

true if there are more tokens; false otherwise.

nextElement

public java.lang.Object nextElement()

Returns the same value as the nextToken method, except that its declared return value is Object rather than String. It exists so that this class can implement the Enumeration interface.

Specified by:

nextElement in interface java.util.Enumeration

Returns:

the next token in the string

Throws:

java.util.NoSuchElementException - if there are no more tokens in this tokenizer's string

countTokens

public int countTokens()

Calculates the number of times that this tokenizer's nextToken method can be called before it generates an exception. The current position is not advanced.

Returns:

the number of tokens remaining in the string using the current delimiter set

reset

public void reset()

Resets this tokenizer's state so the tokenizing starts from the begin.

tokenize

public static java.lang.String[] tokenize(java.lang.String str,
                                          java.lang.String delim,
                                          boolean returnTokens)

Constructs a string tokenizer for the specified string. All characters in the delim argument are the delimiters for separating tokens. If the returnTokens flag is true, then the delimiter characters are also returned as tokens. Each delimiter is returned as a string of length one. If the flag is false, the delimiter characters are skipped and only serve as separators between tokens. Then tokenizes the str and return an String[] array with tokens.

Parameters:

str - a string to be parsed

delim - the delimiters

returnTokens - flag indicating whether to return the delimiters as tokens

Returns:

array with tokens