public class StringTokenizer extends Object implements Enumeration<Object>
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:
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
| Constructor and Description |
|---|
StringTokenizer(String str)
Constructs a string tokenizer for the specified string.
|
StringTokenizer(String str,
String delim)
Constructs a string tokenizer for the specified string.
|
StringTokenizer(String str,
String delim,
boolean returnDelims)
Constructs a string tokenizer for the specified string.
|
| Modifier and Type | Method and Description |
|---|---|
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()
Returns the next token from this string tokenizer.
|
String |
nextToken(String delim)
Returns the next token in this string tokenizer's string.
|
public StringTokenizer(String str)
" \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.str - a string to be parsed.NullPointerException - if str is nullpublic StringTokenizer(String str, String delim)
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.
str - a string to be parsed.delim - the delimiters.NullPointerException - if str is nullpublic StringTokenizer(String str, String delim, boolean returnDelims)
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.
str - a string to be parsed.delim - the delimiters.returnDelims - flag indicating whether to return the delimiters as tokens.NullPointerException - if str is nullpublic int countTokens()
nextToken method can be called before it
generates an exception. The current position is not advanced.nextToken()public boolean hasMoreElements()
hasMoreTokens method. It exists so that this class can implement the
Enumeration interface.hasMoreElements in interface Enumeration<Object>true if there are more tokens; false otherwise.Enumeration,
hasMoreTokens()public boolean hasMoreTokens()
true if and only if there is at least one token in the string after the current position;
false otherwise.public Object nextElement()
nextToken method, except that its declared return value is
Object rather than String. It exists so that this class can implement the
Enumeration interface.nextElement in interface Enumeration<Object>NoSuchElementException - if there are no more tokens in this tokenizer's string.Enumeration,
nextToken()public String nextToken()
NoSuchElementException - if there are no more tokens in this tokenizer's string.public String nextToken(String delim)
delim - the new delimiters.NoSuchElementException - if there are no more tokens in this tokenizer's string.NullPointerException - if delim is null