StringTokenizer

public class StringTokenizer extends Object
implements Enumeration<Object>

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. The StringTokenizer methods do not distinguish among identifiers, numbers, and quoted strings, nor do they 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 returnDelims flag having the value true or false:

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

A StringTokenizer object internally maintains a current position within the string to be tokenized. Some operations advance this current position past the characters processed.

A token is returned by taking a substring of the string that was used to create the StringTokenizer object.

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

     StringTokenizer st = new StringTokenizer("this is a test");
     while (st.hasMoreTokens()) {
         System.out.println(st.nextToken());
     }
 

prints the following output:

     this
     is
     a
     test
 

StringTokenizer is a legacy class that is retained for compatibility reasons although its use is discouraged in new code. It is recommended that anyone seeking this functionality use the split method of String or the java.util.regex package instead.

The following example illustrates how the String.split method can be used to break up a string into its basic tokens:

     String[] result = "this is a test".split("\\s");
     for (int x=0; x<result.length; x++)
         System.out.println(result[x]);
 

prints the following output:

     this
     is
     a
     test
 

See Also

• StreamTokenizer

Public Constructor Summary

	StringTokenizer(String str, String delim, boolean returnDelims) Constructs a string tokenizer for the specified string.
	StringTokenizer(String str, String delim) Constructs a string tokenizer for the specified string.
	StringTokenizer(String str) Constructs a string tokenizer for the specified string.

Public 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.
Object	nextElement() Returns the same value as the nextToken method, except that its declared return value is Object rather than String.
String	nextToken(String delim) Returns the next token in this string tokenizer's string.
String	nextToken() Returns the next token from this string tokenizer.

Inherited Method Summary

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

From interface java.util.Enumeration

abstract boolean	hasMoreElements() Tests if this enumeration contains more elements.
abstract Object	nextElement() Returns the next element of this enumeration if this enumeration object has at least one more element to provide.

Public Constructors

public StringTokenizer (String str, String delim, boolean returnDelims)

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

If the returnDelims 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.

Note that if delim is null, this constructor does not throw an exception. However, trying to invoke other methods on the resulting StringTokenizer may result in a NullPointerException.

Parameters

str	a string to be parsed.
delim	the delimiters.
returnDelims	flag indicating whether to return the delimiters as tokens.

Throws

NullPointerException	if str is null

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. Delimiter characters themselves will not be treated as tokens.

Note that if delim is null, this constructor does not throw an exception. However, trying to invoke other methods on the resulting StringTokenizer may result in a NullPointerException.

Parameters

str	a string to be parsed.
delim	the delimiters.

Throws

NullPointerException	if str is null

public StringTokenizer (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.

Throws

NullPointerException	if str is null

Public Methods

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.

See Also

• nextToken()

public boolean hasMoreElements ()

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

Returns

• true if there are more tokens; false otherwise.

See Also

• Enumeration
• 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.

public 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.

Returns

• the next token in the string.

Throws

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

See Also

• Enumeration
• nextToken()

public String nextToken (String delim)

Returns the next token in this string tokenizer's string. First, the set of characters considered to be delimiters by this StringTokenizer 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

NoSuchElementException	if there are no more tokens in this tokenizer's string.
NullPointerException	if delim is null

public String nextToken ()

Returns the next token from this string tokenizer.

Returns

• the next token from this string tokenizer.

Throws

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