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§3.9 Class StringTokenizer

public  class  java.util.StringTokenizer
    extends  java.lang.Object  (I-§1.12)
    implements java.util.Enumeration  (I-§3.11)
{
        // Constructors
    public StringTokenizer(String  str);	§3.9.1
    public StringTokenizer(String  str, String  delim);	§3.9.2
    public StringTokenizer(String  str, String  delim,	§3.9.3
                                      boolean  returnTokens);
        // Methods
    public int countTokens();	§3.9.4
    public boolean hasMoreElements();	§3.9.5
    public boolean hasMoreTokens();	§3.9.6
    public Object nextElement();	§3.9.7
    public String nextToken();	§3.9.8
    public String nextToken(String  delim);	§3.9.9
}

The string tokenizer class allows an application to break a string into tokens. The tokenization method is much simpler than the one used by the StreamTokenizer class (I-§2.22). The StringTokenizer methods do not distinguish among identifiers, numbers, and quoted strings, not does it recognize and skip comments.

The set of delimiters (the characters that separate tokens) may be specified either at creation time or on a per-token basis.

An instance of StringTokenizer behaves in one of two ways, depending on whether it was created with the returnTokens flag having the value true or false:

If the flag is false, delimiter characters merely serve to separate tokens. A token is a maximal sequence of consecutive characters that are delimiters.
If the flag is true, delimiters characters are considered to be tokens. A token is either one delimiter character, or a maximal sequence of consecutive characters that are not delimiters.

The following is one example of the use of the tokenizer. The code

StringTokenizer  st  =  new  StringTokenizer("this  is  a  test");

while  (st.hasMoreTokens())  {

        println(st.nextToken());

}

Prints the following output:

this

is

a

test

StringTokenizer

public StringTokenizer(String  str)

Constructs a string tokenizer for the specified string. The tokenizer uses the default delimiter set, which is " \t\n\r", the space character, the tab character, the newline character, and the carriage return character.

Parameters:: str -a string to be parsed

StringTokenizer

public StringTokenizer(String  str, String  delim)

Constructs a string tokenizer for the specified string. The characters in the delim argument are the delimiters for separating tokens.

Parameters:: str -a string to be parsed; delim -the delimiters

StringTokenizer

public StringTokenizer(String  str, String  delim,

                                              boolean  returnTokens)

Constructs a string tokenizer for the specified string. The 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.

countTokens

public int countTokens()

Calculates the number of times that this tokenizer's nextToken method (I-§3.9.8) can be called before it generates an exception.

Returns:: the number of tokens remaining in the string using thie current delimiter set.

hasMoreElements

public boolean hasMoreElements()

This method returns the same value as the following hasMoreTokens method. It exists so that this class can implement the enumeration (I-§3.11) interface.

Returns:: true if there are more tokens; false otherwise

hasMoreTokens

public boolean hasMoreTokens()

Returns:: true if there are more tokens available from this tokenizer's string; false otherwise

nextElement

public Object nextElement()

This method returns the same value as the following nextToken method, except that its declared return value is Object rather than String. It exists so that this class can implement the enumeration (I-§3.11) interface.

Returns:: the next token in the string.
Throws: NoSuchElementException (I-§3.14); If there are no more tokens in this tokenizer's string.

nextToken

public String nextToken()

Returns:: the next token from this string tokenizer.
Throws: NoSuchElementException (I-§3.14); If there are no more tokens in this tokenizer's string.

nextToken

public String nextToken(String  delim)

Gets the next token in this stringt tokenizer's string. 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: NoSuchElementException (I-§3.14); If there are no more tokens in the string.

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