- All Implemented Interfaces:
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:
- 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
- Since:
- 1.0
- See Also:
-
Constructor Summary
ConstructorsConstructorDescriptionStringTokenizer(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. -
Method Summary
Modifier and TypeMethodDescriptionintCalculates the number of times that this tokenizer'snextTokenmethod can be called before it generates an exception.booleanReturns the same value as thehasMoreTokensmethod.booleanTests if there are more tokens available from this tokenizer's string.Returns the same value as thenextTokenmethod, except that its declared return value isObjectrather thanString.Returns the next token from this string tokenizer.Returns the next token in this string tokenizer's string.Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitMethods declared in interface java.util.Enumeration
asIterator
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Constructor Details
-
StringTokenizer
Constructs a string tokenizer for the specified string. All characters in thedelimargument are the delimiters for separating tokens.If the
returnDelimsflag istrue, then the delimiter characters are also returned as tokens. Each delimiter is returned as a string of length one. If the flag isfalse, the delimiter characters are skipped and only serve as separators between tokens.Note that if
delimisnull, this constructor does not throw an exception. However, trying to invoke other methods on the resultingStringTokenizermay result in aNullPointerException.- Parameters:
str- a string to be parsed.delim- the delimiters.returnDelims- flag indicating whether to return the delimiters as tokens.- Throws:
NullPointerException- if str isnull
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StringTokenizer
Constructs a string tokenizer for the specified string. The characters in thedelimargument are the delimiters for separating tokens. Delimiter characters themselves will not be treated as tokens.Note that if
delimisnull, this constructor does not throw an exception. However, trying to invoke other methods on the resultingStringTokenizermay result in aNullPointerException.- Parameters:
str- a string to be parsed.delim- the delimiters.- Throws:
NullPointerException- if str isnull
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StringTokenizer
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 isnull
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Method Details
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hasMoreTokens
public boolean hasMoreTokens()Tests if there are more tokens available from this tokenizer's string. If this method returnstrue, then a subsequent call tonextTokenwith no argument will successfully return a token.- Returns:
trueif and only if there is at least one token in the string after the current position;falseotherwise.
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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.
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nextToken
Returns the next token in this string tokenizer's string. First, the set of characters considered to be delimiters by thisStringTokenizerobject is changed to be the characters in the stringdelim. 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 isnull
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hasMoreElements
public boolean hasMoreElements()Returns the same value as thehasMoreTokensmethod. It exists so that this class can implement theEnumerationinterface.- Specified by:
hasMoreElementsin interfaceEnumeration<Object>- Returns:
trueif there are more tokens;falseotherwise.- See Also:
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nextElement
Returns the same value as thenextTokenmethod, except that its declared return value isObjectrather thanString. It exists so that this class can implement theEnumerationinterface.- Specified by:
nextElementin interfaceEnumeration<Object>- Returns:
- the next token in the string.
- Throws:
NoSuchElementException- if there are no more tokens in this tokenizer's string.- See Also:
-
countTokens
public int countTokens()Calculates the number of times that this tokenizer'snextTokenmethod 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:
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