public
class
StringTokenizer
extends Object
implements
Enumeration<Object>
| java.lang.Object | |
| ↳ | java.util.StringTokenizer |
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:
Developers
false, delimiter characters serve to
separate tokens. A token is a maximal sequence of consecutive
characters that are not delimiters.
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:
Public constructors | |
|---|---|
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 methods | |
|---|---|
int
|
countTokens()
Calculates the number of times that this tokenizer's
|
boolean
|
hasMoreElements()
Returns the same value as the |
boolean
|
hasMoreTokens()
Tests if there are more tokens available from this tokenizer's string. |
Object
|
nextElement()
Returns the same value as the |
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 methods | |
|---|---|
 From
class
java.lang.Object
| |
From
interface
java.util.Enumeration
| |
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 |
String:
a string to be parsed. |
delim |
String:
the delimiters. |
returnDelims |
boolean:
flag indicating whether to return the delimiters
as tokens. |
| Throws | |
|---|---|
NullPointerException |
if str is null
|
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 |
String:
a string to be parsed. |
delim |
String:
the delimiters. |
| Throws | |
|---|---|
NullPointerException |
if str is null
|
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 |
String:
a string to be parsed. |
| Throws | |
|---|---|
NullPointerException |
if str is null
|
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 | |
|---|---|
int |
the number of tokens remaining in the string using the current delimiter set. |
See also:
boolean hasMoreElements ()
Returns the same value as the hasMoreTokens
method. It exists so that this class can implement the
Enumeration interface.
| Returns | |
|---|---|
boolean |
true if there are more tokens;
false otherwise. |
See also:
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 | |
|---|---|
boolean |
true if and only if there is at least one token
in the string after the current position; false
otherwise.
|
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 | |
|---|---|
Object |
the next token in the string. |
| Throws | |
|---|---|
NoSuchElementException |
if there are no more tokens in this tokenizer's string. |
See also:
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 |
String:
the new delimiters. |
| Returns | |
|---|---|
String |
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
|
String nextToken ()
Returns the next token from this string tokenizer.
| Returns | |
|---|---|
String |
the next token from this string tokenizer. |
| Throws | |
|---|---|
NoSuchElementException |
if there are no more tokens in this tokenizer's string. |