# Class StringTokenizer

java.lang.Object
java.util.StringTokenizer

All Implemented Interfaces:
  `Enumeration<Object>`

public class StringTokenizer extends Object implements Enumeration<Object>
The `StringTokenizer` class allows an application to break a string into tokens by performing code point comparison. The `StringTokenizer` methods do not distinguish among identifiers, numbers, and quoted strings, nor do they recognize and skip comments.

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

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

- If returnDelims is `false`, delimiter code points serve to separate tokens. A token is a maximal sequence of consecutive code points that are not delimiters.
- If returnDelims is `true`, delimiter code points are themselves considered to be tokens. In this case a token will be received for each delimiter code point.

A token is thus either one delimiter code point, or a maximal sequence of consecutive code points 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 code point processed.

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

Here's an example of the use of the default delimiter `StringTokenizer` :

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

This prints the following output:

>         this
>         is
>         a
>         test

Here's an example of how to use a `StringTokenizer` with a user specified delimiter:

>     StringTokenizer st = new StringTokenizer(
>             "this is a test with supplementary characters ?𐀀?",
>             " 𐀀");
>     while (st.hasMoreTokens()) {
>         println(st.nextToken());
>     }

This prints the following output:

>         this
>         is
>         a
>         test
>         with
>         supplementary
>         characters
>         ?
>         ?

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `StringTokenizer(String string)`
  Constructs a new `StringTokenizer` for the parameter string using whitespace as the delimiter.
  `StringTokenizer(String string, String delimiters)`
  Constructs a new `StringTokenizer` for the parameter string using the specified delimiters.
  `StringTokenizer(String string, String delimiters, boolean returnDelimiters)`
  Constructs a new `StringTokenizer` for the parameter string using the specified delimiters, returning the delimiters as tokens if the parameter `returnDelimiters` is `true`.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `int`
  `countTokens()`
  Returns the number of unprocessed tokens remaining in the string.
  `boolean`
  `hasMoreElements()`
  Returns `true` if unprocessed tokens remain.
  `boolean`
  `hasMoreTokens()`
  Returns `true` if unprocessed tokens remain.
  `Object`
  `nextElement()`
  Returns the next token in the string as an `Object`.
  `String`
  `nextToken()`
  Returns the next token in the string as a `String`.
  `String`
  `nextToken(String delims)`
  Returns the next token in the string as a `String`.

  ### Methods inherited from class Object

  `clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- ## Constructor Details

  - ### StringTokenizer

    public StringTokenizer(String string)
    Constructs a new `StringTokenizer` for the parameter string using whitespace as the delimiter. The `returnDelimiters` flag is set to `false`.
    Parameters:
      `string` - the string to be tokenized.

  - ### StringTokenizer

    public StringTokenizer(String string, String delimiters)
    Constructs a new `StringTokenizer` for the parameter string using the specified delimiters. The `returnDelimiters` flag is set to `false`. If `delimiters` is `null`, this constructor doesn't throw an `Exception`, but later calls to some methods might throw a `NullPointerException`.
    Parameters:
      `string` - the string to be tokenized.
      `delimiters` - the delimiters to use.

  - ### StringTokenizer

    public StringTokenizer(String string, String delimiters, boolean returnDelimiters)
    Constructs a new `StringTokenizer` for the parameter string using the specified delimiters, returning the delimiters as tokens if the parameter `returnDelimiters` is `true`. If `delimiters` is null this constructor doesn't throw an `Exception`, but later calls to some methods might throw a `NullPointerException`.
    Parameters:
      `string` - the string to be tokenized.
      `delimiters` - the delimiters to use.
      `returnDelimiters` - `true` to return each delimiter as a token.

- ## Method Details

  - ### countTokens

    public int countTokens()
    Returns the number of unprocessed tokens remaining in the string.
    Returns:
      number of tokens that can be retreived before an `Exception` will result from a call to `nextToken()`.

  - ### hasMoreElements

    public boolean hasMoreElements()
    Returns `true` if unprocessed tokens remain. This method is implemented in order to satisfy the `Enumeration` interface.
    Specified by:
      `hasMoreElements` in interface `Enumeration<Object>`
    Returns:
      `true` if unprocessed tokens remain.

  - ### hasMoreTokens

    public boolean hasMoreTokens()
    Returns `true` if unprocessed tokens remain.
    Returns:
      `true` if unprocessed tokens remain.

  - ### nextElement

    public Object nextElement()
    Returns the next token in the string as an `Object`. This method is implemented in order to satisfy the `Enumeration` interface.
    Specified by:
      `nextElement` in interface `Enumeration<Object>`
    Returns:
      next token in the string as an `Object`
    Throws:
      `NoSuchElementException` - if no tokens remain.

  - ### nextToken

    public String nextToken()
    Returns the next token in the string as a `String`.
    Returns:
      next token in the string as a `String`.
    Throws:
      `NoSuchElementException` - if no tokens remain.

  - ### nextToken

    public String nextToken(String delims)
    Returns the next token in the string as a `String`. The delimiters used are changed to the specified delimiters.
    Parameters:
      `delims` - the new delimiters to use.
    Returns:
      next token in the string as a `String`.
    Throws:
      `NoSuchElementException` - if no tokens remain.