java.util

## Class Scanner

- java.lang.Object
- - java.util.Scanner

- All Implemented Interfaces:
    Iterator<String>

      public final class Scanner
      extends Object
      implements Iterator<String>

  A simple text scanner which can parse primitive types and strings using regular expressions.

  A `Scanner` breaks its input into tokens using a delimiter pattern, which by default matches whitespace. The resulting tokens may then be converted into values of different types using the various `next` methods.

  For example, this code allows a user to read a number from `System.in`:

  >          Scanner sc = new Scanner(System.in);
  >          int i = sc.nextInt();

  As another example, this code allows `long` types to be assigned from entries in a file `myNumbers`:

  >           Scanner sc = new Scanner(new File("myNumbers"));
  >           while (sc.hasNextLong()) {
  >               long aLong = sc.nextLong();
  >           }

  The scanner can also use delimiters other than whitespace. This example reads several items in from a string:

  >          String input = "1 fish 2 fish red fish blue fish";
  >          Scanner s = new Scanner(input).useDelimiter("\\s*fish\\s*");
  >          System.out.println(s.nextInt());
  >          System.out.println(s.nextInt());
  >          System.out.println(s.next());
  >          System.out.println(s.next());
  >          s.close();

  prints the following output:

  >          1
  >          2
  >          red
  >          blue

  The same output can be generated with this code, which uses a regular expression to parse all four tokens at once:

  >          String input = "1 fish 2 fish red fish blue fish";
  >          Scanner s = new Scanner(input);
  >          s.findInLine("(\\d+) fish (\\d+) fish (\\w+) fish (\\w+)");
  >          MatchResult result = s.match();
  >          for (int i=1; i<=result.groupCount(); i++)
  >              System.out.println(result.group(i));
  >          s.close();

  The default whitespace delimiter used by a scanner is as recognized by `Character`.`isWhitespace`. The `reset()` method will reset the value of the scanner's delimiter to the default whitespace delimiter regardless of whether it was previously changed.

  A scanning operation may block waiting for input.

  The `next()` and `hasNext()` methods and their primitive-type companion methods (such as `nextInt()` and `hasNextInt()`) first skip any input that matches the delimiter pattern, and then attempt to return the next token. Both `hasNext` and `next` methods may block waiting for further input. Whether a `hasNext` method blocks has no connection to whether or not its associated `next` method will block.

  The `findInLine(java.lang.String)`, `findWithinHorizon(java.lang.String, int)`, and `skip(java.util.regex.Pattern)` methods operate independently of the delimiter pattern. These methods will attempt to match the specified pattern with no regard to delimiters in the input and thus can be used in special circumstances where delimiters are not relevant. These methods may block waiting for more input.

  When a scanner throws an `InputMismatchException`, the scanner will not pass the token that caused the exception, so that it may be retrieved or skipped via some other method.

  Depending upon the type of delimiting pattern, empty tokens may be returned. For example, the pattern `"\\s+"` will return no empty tokens since it matches multiple instances of the delimiter. The delimiting pattern `"\\s"` could return empty tokens since it only passes one space at a time.

  A scanner can read text from any object which implements the `Readable` interface. If an invocation of the underlying readable's `Readable.read(java.nio.CharBuffer)` method throws an `IOException` then the scanner assumes that the end of the input has been reached. The most recent `IOException` thrown by the underlying readable can be retrieved via the `ioException()` method.

  When a `Scanner` is closed, it will close its input source if the source implements the `Closeable` interface.

  A `Scanner` is not safe for multithreaded use without external synchronization.

  Unless otherwise mentioned, passing a `null` parameter into any method of a `Scanner` will cause a `NullPointerException` to be thrown.

  A scanner will default to interpreting numbers as decimal unless a different radix has been set by using the `useRadix(int)` method. The `reset()` method will reset the value of the scanner's radix to `10` regardless of whether it was previously changed.

  #### Localized numbers

  An instance of this class is capable of scanning numbers in the standard formats as well as in the formats of the scanner's locale. A scanner's initial locale is the value returned by the `Locale.getDefault()` method; it may be changed via the `useLocale(java.util.Locale)` method. The `reset()` method will reset the value of the scanner's locale to the initial locale regardless of whether it was previously changed.

  The localized formats are defined in terms of the following parameters, which for a particular locale are taken from that locale's `DecimalFormat` object, `df`, and its and `DecimalFormatSymbols` object, `dfs`.

  > LocalGroupSeparator | The character used to separate thousands groups, i.e., `dfs.``getGroupingSeparator()`
  > LocalDecimalSeparator | The character used for the decimal point, i.e., `dfs.``getDecimalSeparator()`
  > LocalPositivePrefix | The string that appears before a positive number (may be empty), i.e., `df.``getPositivePrefix()`
  > LocalPositiveSuffix | The string that appears after a positive number (may be empty), i.e., `df.``getPositiveSuffix()`
  > LocalNegativePrefix | The string that appears before a negative number (may be empty), i.e., `df.``getNegativePrefix()`
  > LocalNegativeSuffix | The string that appears after a negative number (may be empty), i.e., `df.``getNegativeSuffix()`
  > LocalNaN | The string that represents not-a-number for floating-point values, i.e., `dfs.``getNaN()`
  > LocalInfinity | The string that represents infinity for floating-point values, i.e., `dfs.``getInfinity()`

  #### Number syntax

  The strings that can be parsed as numbers by an instance of this class are specified in terms of the following regular-expression grammar, where Rmax is the highest digit in the radix being used (for example, Rmax is 9 in base 10).

  NonASCIIDigit :: | = A non-ASCII character c for which `Character.isDigit``(c)` returns true
  Non0Digit :: | `= [1-`Rmax`] |` NonASCIIDigit
  Digit :: | `= [0-`Rmax`] |` NonASCIIDigit
  GroupedNumeral :: |
  `= (` | Non0Digit`` Digit`?` Digit`?`
  | `(` LocalGroupSeparator`` Digit`` Digit`` Digit`)+ )`
  Numeral :: | `= ( (` Digit`+ ) |` GroupedNumeral`)`
  Integer :: | `= ( [-+]? (` Numeral`) )`
  | `|` LocalPositivePrefix`` Numeral`` LocalPositiveSuffix
  | `|` LocalNegativePrefix`` Numeral`` LocalNegativeSuffix
  DecimalNumeral :: | `=` Numeral
  | `|` Numeral`` LocalDecimalSeparator`` Digit`*`
  | `|` LocalDecimalSeparator`` Digit`+`
  Exponent :: | `= ( [eE] [+-]?` Digit`+ )`
  Decimal :: | `= ( [-+]?` DecimalNumeral`` Exponent`? )`
  | `|` LocalPositivePrefix`` DecimalNumeral`` LocalPositiveSuffix Exponent`?`
  | `|` LocalNegativePrefix`` DecimalNumeral`` LocalNegativeSuffix Exponent`?`
  HexFloat :: | `= [-+]? 0[xX][0-9a-fA-F]*\.[0-9a-fA-F]+ ([pP][-+]?[0-9]+)?`
  NonNumber :: | `= NaN |` LocalNan`| Infinity |` LocalInfinity
  SignedNonNumber :: | `= ( [-+]?` NonNumber`)`
  | `|` LocalPositivePrefix`` NonNumber`` LocalPositiveSuffix
  | `|` LocalNegativePrefix`` NonNumber`` LocalNegativeSuffix
  Float :: | `=` Decimal``
  | `|` HexFloat``
  | `|` SignedNonNumber``

  Whitespace is not significant in the above regular expressions.

  Since:
    1.5

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `Scanner(File source)` Constructs a new `Scanner` that produces values scanned from the specified file.
    `Scanner(File source, String charsetName)` Constructs a new `Scanner` that produces values scanned from the specified file.
    `Scanner(InputStream source)` Constructs a new `Scanner` that produces values scanned from the specified input stream.
    `Scanner(InputStream source, String charsetName)` Constructs a new `Scanner` that produces values scanned from the specified input stream.
    `Scanner(Readable source)` Constructs a new `Scanner` that produces values scanned from the specified source.
    `Scanner(ReadableByteChannel source)` Constructs a new `Scanner` that produces values scanned from the specified channel.
    `Scanner(ReadableByteChannel source, String charsetName)` Constructs a new `Scanner` that produces values scanned from the specified channel.
    `Scanner(String source)` Constructs a new `Scanner` that produces values scanned from the specified string.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `close()` Closes this scanner.
    `Pattern` | `delimiter()` Returns the `Pattern` this `Scanner` is currently using to match delimiters.
    `String` | `findInLine(Pattern pattern)` Attempts to find the next occurrence of the specified pattern ignoring delimiters.
    `String` | `findInLine(String pattern)` Attempts to find the next occurrence of a pattern constructed from the specified string, ignoring delimiters.
    `String` | `findWithinHorizon(Pattern pattern, int horizon)` Attempts to find the next occurrence of the specified pattern.
    `String` | `findWithinHorizon(String pattern, int horizon)` Attempts to find the next occurrence of a pattern constructed from the specified string, ignoring delimiters.
    `boolean` | `hasNext()` Returns true if this scanner has another token in its input.
    `boolean` | `hasNext(Pattern pattern)` Returns true if the next complete token matches the specified pattern.
    `boolean` | `hasNext(String pattern)` Returns true if the next token matches the pattern constructed from the specified string.
    `boolean` | `hasNextBigDecimal()` Returns true if the next token in this scanner's input can be interpreted as a `BigDecimal` using the `nextBigDecimal()` method.
    `boolean` | `hasNextBigInteger()` Returns true if the next token in this scanner's input can be interpreted as a `BigInteger` in the default radix using the `nextBigInteger()` method.
    `boolean` | `hasNextBigInteger(int radix)` Returns true if the next token in this scanner's input can be interpreted as a `BigInteger` in the specified radix using the `nextBigInteger()` method.
    `boolean` | `hasNextBoolean()` Returns true if the next token in this scanner's input can be interpreted as a boolean value using a case insensitive pattern created from the string "true|false".
    `boolean` | `hasNextByte()` Returns true if the next token in this scanner's input can be interpreted as a byte value in the default radix using the `nextByte()` method.
    `boolean` | `hasNextByte(int radix)` Returns true if the next token in this scanner's input can be interpreted as a byte value in the specified radix using the `nextByte()` method.
    `boolean` | `hasNextDouble()` Returns true if the next token in this scanner's input can be interpreted as a double value using the `nextDouble()` method.
    `boolean` | `hasNextFloat()` Returns true if the next token in this scanner's input can be interpreted as a float value using the `nextFloat()` method.
    `boolean` | `hasNextInt()` Returns true if the next token in this scanner's input can be interpreted as an int value in the default radix using the `nextInt()` method.
    `boolean` | `hasNextInt(int radix)` Returns true if the next token in this scanner's input can be interpreted as an int value in the specified radix using the `nextInt()` method.
    `boolean` | `hasNextLine()` Returns true if there is another line in the input of this scanner.
    `boolean` | `hasNextLong()` Returns true if the next token in this scanner's input can be interpreted as a long value in the default radix using the `nextLong()` method.
    `boolean` | `hasNextLong(int radix)` Returns true if the next token in this scanner's input can be interpreted as a long value in the specified radix using the `nextLong()` method.
    `boolean` | `hasNextShort()` Returns true if the next token in this scanner's input can be interpreted as a short value in the default radix using the `nextShort()` method.
    `boolean` | `hasNextShort(int radix)` Returns true if the next token in this scanner's input can be interpreted as a short value in the specified radix using the `nextShort()` method.
    `IOException` | `ioException()` Returns the `IOException` last thrown by this `Scanner`'s underlying `Readable`.
    `Locale` | `locale()` Returns this scanner's locale.
    `MatchResult` | `match()` Returns the match result of the last scanning operation performed by this scanner.
    `String` | `next()` Finds and returns the next complete token from this scanner.
    `String` | `next(Pattern pattern)` Returns the next token if it matches the specified pattern.
    `String` | `next(String pattern)` Returns the next token if it matches the pattern constructed from the specified string.
    `BigDecimal` | `nextBigDecimal()` Scans the next token of the input as a `BigDecimal`.
    `BigInteger` | `nextBigInteger()` Scans the next token of the input as a `BigInteger`.
    `BigInteger` | `nextBigInteger(int radix)` Scans the next token of the input as a `BigInteger`.
    `boolean` | `nextBoolean()` Scans the next token of the input into a boolean value and returns that value.
    `byte` | `nextByte()` Scans the next token of the input as a `byte`.
    `byte` | `nextByte(int radix)` Scans the next token of the input as a `byte`.
    `double` | `nextDouble()` Scans the next token of the input as a `double`.
    `float` | `nextFloat()` Scans the next token of the input as a `float`.
    `int` | `nextInt()` Scans the next token of the input as an `int`.
    `int` | `nextInt(int radix)` Scans the next token of the input as an `int`.
    `String` | `nextLine()` Advances this scanner past the current line and returns the input that was skipped.
    `long` | `nextLong()` Scans the next token of the input as a `long`.
    `long` | `nextLong(int radix)` Scans the next token of the input as a `long`.
    `short` | `nextShort()` Scans the next token of the input as a `short`.
    `short` | `nextShort(int radix)` Scans the next token of the input as a `short`.
    `int` | `radix()` Returns this scanner's default radix.
    `void` | `remove()` The remove operation is not supported by this implementation of `Iterator`.
    `Scanner` | `reset()` Resets this scanner.
    `Scanner` | `skip(Pattern pattern)` Skips input that matches the specified pattern, ignoring delimiters.
    `Scanner` | `skip(String pattern)` Skips input that matches a pattern constructed from the specified string.
    `String` | `toString()` Returns the string representation of this `Scanner`.
    `Scanner` | `useDelimiter(Pattern pattern)` Sets this scanner's delimiting pattern to the specified pattern.
    `Scanner` | `useDelimiter(String pattern)` Sets this scanner's delimiting pattern to a pattern constructed from the specified `String`.
    `Scanner` | `useLocale(Locale locale)` Sets this scanner's locale to the specified locale.
    `Scanner` | `useRadix(int radix)` Sets this scanner's default radix to the specified radix.

    - ### Methods inherited from class java.lang.Object

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

- - ### Constructor Detail

    - #### Scanner

          public Scanner(Readable source)

      Constructs a new `Scanner` that produces values scanned from the specified source.
      Parameters:
        `source` - A character source implementing the `Readable` interface

    - #### Scanner

          public Scanner(InputStream source)

      Constructs a new `Scanner` that produces values scanned from the specified input stream. Bytes from the stream are converted into characters using the underlying platform's default charset.
      Parameters:
        `source` - An input stream to be scanned

    - #### Scanner

          public Scanner(InputStream source,
                 String charsetName)

      Constructs a new `Scanner` that produces values scanned from the specified input stream. Bytes from the stream are converted into characters using the specified charset.
      Parameters:
        `source` - An input stream to be scanned
        `charsetName` - The encoding type used to convert bytes from the stream into characters to be scanned
      Throws:
        `IllegalArgumentException` - if the specified character set does not exist

    - #### Scanner

          public Scanner(File source)
                  throws FileNotFoundException

      Constructs a new `Scanner` that produces values scanned from the specified file. Bytes from the file are converted into characters using the underlying platform's default charset.
      Parameters:
        `source` - A file to be scanned
      Throws:
        `FileNotFoundException` - if source is not found

    - #### Scanner

          public Scanner(File source,
                 String charsetName)
                  throws FileNotFoundException

      Constructs a new `Scanner` that produces values scanned from the specified file. Bytes from the file are converted into characters using the specified charset.
      Parameters:
        `source` - A file to be scanned
        `charsetName` - The encoding type used to convert bytes from the file into characters to be scanned
      Throws:
        `FileNotFoundException` - if source is not found
        `IllegalArgumentException` - if the specified encoding is not found

    - #### Scanner

          public Scanner(String source)

      Constructs a new `Scanner` that produces values scanned from the specified string.
      Parameters:
        `source` - A string to scan

    - #### Scanner

          public Scanner(ReadableByteChannel source)

      Constructs a new `Scanner` that produces values scanned from the specified channel. Bytes from the source are converted into characters using the underlying platform's default charset.
      Parameters:
        `source` - A channel to scan

    - #### Scanner

          public Scanner(ReadableByteChannel source,
                 String charsetName)

      Constructs a new `Scanner` that produces values scanned from the specified channel. Bytes from the source are converted into characters using the specified charset.
      Parameters:
        `source` - A channel to scan
        `charsetName` - The encoding type used to convert bytes from the channel into characters to be scanned
      Throws:
        `IllegalArgumentException` - if the specified character set does not exist

  - ### Method Detail

    - #### close

          public void close()

      Closes this scanner.

      If this scanner has not yet been closed then if its underlying readable also implements the `Closeable` interface then the readable's `close` method will be invoked. If this scanner is already closed then invoking this method will have no effect.

      Attempting to perform search operations after a scanner has been closed will result in an `IllegalStateException`.

    - #### ioException

          public IOException ioException()

      Returns the `IOException` last thrown by this `Scanner`'s underlying `Readable`. This method returns `null` if no such exception exists.
      Returns:
        the last exception thrown by this scanner's readable

    - #### delimiter

          public Pattern delimiter()

      Returns the `Pattern` this `Scanner` is currently using to match delimiters.
      Returns:
        this scanner's delimiting pattern.

    - #### useDelimiter

          public Scanner useDelimiter(Pattern pattern)

      Sets this scanner's delimiting pattern to the specified pattern.
      Parameters:
        `pattern` - A delimiting pattern
      Returns:
        this scanner

    - #### useDelimiter

          public Scanner useDelimiter(String pattern)

      Sets this scanner's delimiting pattern to a pattern constructed from the specified `String`.

      An invocation of this method of the form `useDelimiter(pattern)` behaves in exactly the same way as the invocation `useDelimiter(Pattern.compile(pattern))`.

      Invoking the `reset()` method will set the scanner's delimiter to the default.

      Parameters:
        `pattern` - A string specifying a delimiting pattern
      Returns:
        this scanner

    - #### locale

          public Locale locale()

      Returns this scanner's locale.

      A scanner's locale affects many elements of its default primitive matching regular expressions; see localized numbers above.

      Returns:
        this scanner's locale

    - #### useLocale

          public Scanner useLocale(Locale locale)

      Sets this scanner's locale to the specified locale.

      A scanner's locale affects many elements of its default primitive matching regular expressions; see localized numbers above.

      Invoking the `reset()` method will set the scanner's locale to the initial locale.

      Parameters:
        `locale` - A string specifying the locale to use
      Returns:
        this scanner

    - #### radix

          public int radix()

      Returns this scanner's default radix.

      A scanner's radix affects elements of its default number matching regular expressions; see localized numbers above.

      Returns:
        the default radix of this scanner

    - #### useRadix

          public Scanner useRadix(int radix)

      Sets this scanner's default radix to the specified radix.

      A scanner's radix affects elements of its default number matching regular expressions; see localized numbers above.

      If the radix is less than `Character.MIN_RADIX` or greater than `Character.MAX_RADIX`, then an `IllegalArgumentException` is thrown.

      Invoking the `reset()` method will set the scanner's radix to `10`.

      Parameters:
        `radix` - The radix to use when scanning numbers
      Returns:
        this scanner
      Throws:
        `IllegalArgumentException` - if radix is out of range

    - #### match

          public MatchResult match()

      Returns the match result of the last scanning operation performed by this scanner. This method throws `IllegalStateException` if no match has been performed, or if the last match was not successful.

      The various `next`methods of `Scanner` make a match result available if they complete without throwing an exception. For instance, after an invocation of the `nextInt()` method that returned an int, this method returns a `MatchResult` for the search of the Integer regular expression defined above. Similarly the `findInLine(java.lang.String)`, `findWithinHorizon(java.lang.String, int)`, and `skip(java.util.regex.Pattern)` methods will make a match available if they succeed.

      Returns:
        a match result for the last match operation
      Throws:
        `IllegalStateException` - If no match result is available

    - #### toString

          public String toString()

      Returns the string representation of this `Scanner`. The string representation of a `Scanner` contains information that may be useful for debugging. The exact format is unspecified.

      Overrides:
        `toString` in class `Object`
      Returns:
        The string representation of this scanner

    - #### hasNext

          public boolean hasNext()

      Returns true if this scanner has another token in its input. This method may block while waiting for input to scan. The scanner does not advance past any input.
      Specified by:
        `hasNext` in interface `Iterator<String>`
      Returns:
        true if and only if this scanner has another token
      Throws:
        `IllegalStateException` - if this scanner is closed
      See Also:
        `Iterator`

    - #### next

          public String next()

      Finds and returns the next complete token from this scanner. A complete token is preceded and followed by input that matches the delimiter pattern. This method may block while waiting for input to scan, even if a previous invocation of `hasNext()` returned `true`.
      Specified by:
        `next` in interface `Iterator<String>`
      Returns:
        the next token
      Throws:
        `NoSuchElementException` - if no more tokens are available
        `IllegalStateException` - if this scanner is closed
      See Also:
        `Iterator`

    - #### remove

          public void remove()

      The remove operation is not supported by this implementation of `Iterator`.
      Specified by:
        `remove` in interface `Iterator<String>`
      Throws:
        `UnsupportedOperationException` - if this method is invoked.
      See Also:
        `Iterator`

    - #### hasNext

          public boolean hasNext(String pattern)

      Returns true if the next token matches the pattern constructed from the specified string. The scanner does not advance past any input.

      An invocation of this method of the form `hasNext(pattern)` behaves in exactly the same way as the invocation `hasNext(Pattern.compile(pattern))`.

      Parameters:
        `pattern` - a string specifying the pattern to scan
      Returns:
        true if and only if this scanner has another token matching the specified pattern
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### next

          public String next(String pattern)

      Returns the next token if it matches the pattern constructed from the specified string. If the match is successful, the scanner advances past the input that matched the pattern.

      An invocation of this method of the form `next(pattern)` behaves in exactly the same way as the invocation `next(Pattern.compile(pattern))`.

      Parameters:
        `pattern` - a string specifying the pattern to scan
      Returns:
        the next token
      Throws:
        `NoSuchElementException` - if no such tokens are available
        `IllegalStateException` - if this scanner is closed

    - #### hasNext

          public boolean hasNext(Pattern pattern)

      Returns true if the next complete token matches the specified pattern. A complete token is prefixed and postfixed by input that matches the delimiter pattern. This method may block while waiting for input. The scanner does not advance past any input.
      Parameters:
        `pattern` - the pattern to scan for
      Returns:
        true if and only if this scanner has another token matching the specified pattern
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### next

          public String next(Pattern pattern)

      Returns the next token if it matches the specified pattern. This method may block while waiting for input to scan, even if a previous invocation of `hasNext(Pattern)` returned `true`. If the match is successful, the scanner advances past the input that matched the pattern.
      Parameters:
        `pattern` - the pattern to scan for
      Returns:
        the next token
      Throws:
        `NoSuchElementException` - if no more tokens are available
        `IllegalStateException` - if this scanner is closed

    - #### hasNextLine

          public boolean hasNextLine()

      Returns true if there is another line in the input of this scanner. This method may block while waiting for input. The scanner does not advance past any input.
      Returns:
        true if and only if this scanner has another line of input
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### nextLine

          public String nextLine()

      Advances this scanner past the current line and returns the input that was skipped. This method returns the rest of the current line, excluding any line separator at the end. The position is set to the beginning of the next line.

      Since this method continues to search through the input looking for a line separator, it may buffer all of the input searching for the line to skip if no line separators are present.

      Returns:
        the line that was skipped
      Throws:
        `NoSuchElementException` - if no line was found
        `IllegalStateException` - if this scanner is closed

    - #### findInLine

          public String findInLine(String pattern)

      Attempts to find the next occurrence of a pattern constructed from the specified string, ignoring delimiters.

      An invocation of this method of the form `findInLine(pattern)` behaves in exactly the same way as the invocation `findInLine(Pattern.compile(pattern))`.

      Parameters:
        `pattern` - a string specifying the pattern to search for
      Returns:
        the text that matched the specified pattern
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### findInLine

          public String findInLine(Pattern pattern)

      Attempts to find the next occurrence of the specified pattern ignoring delimiters. If the pattern is found before the next line separator, the scanner advances past the input that matched and returns the string that matched the pattern. If no such pattern is detected in the input up to the next line separator, then `null` is returned and the scanner's position is unchanged. This method may block waiting for input that matches the pattern.

      Since this method continues to search through the input looking for the specified pattern, it may buffer all of the input searching for the desired token if no line separators are present.

      Parameters:
        `pattern` - the pattern to scan for
      Returns:
        the text that matched the specified pattern
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### findWithinHorizon

          public String findWithinHorizon(String pattern,
                                 int horizon)

      Attempts to find the next occurrence of a pattern constructed from the specified string, ignoring delimiters.

      An invocation of this method of the form `findWithinHorizon(pattern)` behaves in exactly the same way as the invocation `findWithinHorizon(Pattern.compile(pattern, horizon))`.

      Parameters:
        `pattern` - a string specifying the pattern to search for
      Returns:
        the text that matched the specified pattern
      Throws:
        `IllegalStateException` - if this scanner is closed
        `IllegalArgumentException` - if horizon is negative

    - #### findWithinHorizon

          public String findWithinHorizon(Pattern pattern,
                                 int horizon)

      Attempts to find the next occurrence of the specified pattern.

      This method searches through the input up to the specified search horizon, ignoring delimiters. If the pattern is found the scanner advances past the input that matched and returns the string that matched the pattern. If no such pattern is detected then the null is returned and the scanner's position remains unchanged. This method may block waiting for input that matches the pattern.

      A scanner will never search more than `horizon` code points beyond its current position. Note that a match may be clipped by the horizon; that is, an arbitrary match result may have been different if the horizon had been larger. The scanner treats the horizon as a transparent, non-anchoring bound (see `Matcher.useTransparentBounds(boolean)` and `Matcher.useAnchoringBounds(boolean)`).

      If horizon is `0`, then the horizon is ignored and this method continues to search through the input looking for the specified pattern without bound. In this case it may buffer all of the input searching for the pattern.

      If horizon is negative, then an IllegalArgumentException is thrown.

      Parameters:
        `pattern` - the pattern to scan for
      Returns:
        the text that matched the specified pattern
      Throws:
        `IllegalStateException` - if this scanner is closed
        `IllegalArgumentException` - if horizon is negative

    - #### skip

          public Scanner skip(Pattern pattern)

      Skips input that matches the specified pattern, ignoring delimiters. This method will skip input if an anchored match of the specified pattern succeeds.

      If a match to the specified pattern is not found at the current position, then no input is skipped and a `NoSuchElementException` is thrown.

      Since this method seeks to match the specified pattern starting at the scanner's current position, patterns that can match a lot of input (".*", for example) may cause the scanner to buffer a large amount of input.

      Note that it is possible to skip something without risking a `NoSuchElementException` by using a pattern that can match nothing, e.g., `sc.skip("[ \t]*")`.

      Parameters:
        `pattern` - a string specifying the pattern to skip over
      Returns:
        this scanner
      Throws:
        `NoSuchElementException` - if the specified pattern is not found
        `IllegalStateException` - if this scanner is closed

    - #### skip

          public Scanner skip(String pattern)

      Skips input that matches a pattern constructed from the specified string.

      An invocation of this method of the form `skip(pattern)` behaves in exactly the same way as the invocation `skip(Pattern.compile(pattern))`.

      Parameters:
        `pattern` - a string specifying the pattern to skip over
      Returns:
        this scanner
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### hasNextBoolean

          public boolean hasNextBoolean()

      Returns true if the next token in this scanner's input can be interpreted as a boolean value using a case insensitive pattern created from the string "true|false". The scanner does not advance past the input that matched.
      Returns:
        true if and only if this scanner's next token is a valid boolean value
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### nextBoolean

          public boolean nextBoolean()

      Scans the next token of the input into a boolean value and returns that value. This method will throw `InputMismatchException` if the next token cannot be translated into a valid boolean value. If the match is successful, the scanner advances past the input that matched.
      Returns:
        the boolean scanned from the input
      Throws:
        `InputMismatchException` - if the next token is not a valid boolean
        `NoSuchElementException` - if input is exhausted
        `IllegalStateException` - if this scanner is closed

    - #### hasNextByte

          public boolean hasNextByte()

      Returns true if the next token in this scanner's input can be interpreted as a byte value in the default radix using the `nextByte()` method. The scanner does not advance past any input.
      Returns:
        true if and only if this scanner's next token is a valid byte value
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### hasNextByte

          public boolean hasNextByte(int radix)

      Returns true if the next token in this scanner's input can be interpreted as a byte value in the specified radix using the `nextByte()` method. The scanner does not advance past any input.
      Parameters:
        `radix` - the radix used to interpret the token as a byte value
      Returns:
        true if and only if this scanner's next token is a valid byte value
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### nextByte

          public byte nextByte()

      Scans the next token of the input as a `byte`.

      An invocation of this method of the form `nextByte()` behaves in exactly the same way as the invocation `nextByte(radix)`, where `radix` is the default radix of this scanner.

      Returns:
        the `byte` scanned from the input
      Throws:
        `InputMismatchException` - if the next token does not match the Integer regular expression, or is out of range
        `NoSuchElementException` - if input is exhausted
        `IllegalStateException` - if this scanner is closed

    - #### nextByte

          public byte nextByte(int radix)

      Scans the next token of the input as a `byte`. This method will throw `InputMismatchException` if the next token cannot be translated into a valid byte value as described below. If the translation is successful, the scanner advances past the input that matched.

      If the next token matches the Integer regular expression defined above then the token is converted into a `byte` value as if by removing all locale specific prefixes, group separators, and locale specific suffixes, then mapping non-ASCII digits into ASCII digits via `Character.digit`, prepending a negative sign (-) if the locale specific negative prefixes and suffixes were present, and passing the resulting string to `Byte.parseByte` with the specified radix.

      Parameters:
        `radix` - the radix used to interpret the token as a byte value
      Returns:
        the `byte` scanned from the input
      Throws:
        `InputMismatchException` - if the next token does not match the Integer regular expression, or is out of range
        `NoSuchElementException` - if input is exhausted
        `IllegalStateException` - if this scanner is closed

    - #### hasNextShort

          public boolean hasNextShort()

      Returns true if the next token in this scanner's input can be interpreted as a short value in the default radix using the `nextShort()` method. The scanner does not advance past any input.
      Returns:
        true if and only if this scanner's next token is a valid short value in the default radix
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### hasNextShort

          public boolean hasNextShort(int radix)

      Returns true if the next token in this scanner's input can be interpreted as a short value in the specified radix using the `nextShort()` method. The scanner does not advance past any input.
      Parameters:
        `radix` - the radix used to interpret the token as a short value
      Returns:
        true if and only if this scanner's next token is a valid short value in the specified radix
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### nextShort

          public short nextShort()

      Scans the next token of the input as a `short`.

      An invocation of this method of the form `nextShort()` behaves in exactly the same way as the invocation `nextShort(radix)`, where `radix` is the default radix of this scanner.

      Returns:
        the `short` scanned from the input
      Throws:
        `InputMismatchException` - if the next token does not match the Integer regular expression, or is out of range
        `NoSuchElementException` - if input is exhausted
        `IllegalStateException` - if this scanner is closed

    - #### nextShort

          public short nextShort(int radix)

      Scans the next token of the input as a `short`. This method will throw `InputMismatchException` if the next token cannot be translated into a valid short value as described below. If the translation is successful, the scanner advances past the input that matched.

      If the next token matches the Integer regular expression defined above then the token is converted into a `short` value as if by removing all locale specific prefixes, group separators, and locale specific suffixes, then mapping non-ASCII digits into ASCII digits via `Character.digit`, prepending a negative sign (-) if the locale specific negative prefixes and suffixes were present, and passing the resulting string to `Short.parseShort` with the specified radix.

      Parameters:
        `radix` - the radix used to interpret the token as a short value
      Returns:
        the `short` scanned from the input
      Throws:
        `InputMismatchException` - if the next token does not match the Integer regular expression, or is out of range
        `NoSuchElementException` - if input is exhausted
        `IllegalStateException` - if this scanner is closed

    - #### hasNextInt

          public boolean hasNextInt()

      Returns true if the next token in this scanner's input can be interpreted as an int value in the default radix using the `nextInt()` method. The scanner does not advance past any input.
      Returns:
        true if and only if this scanner's next token is a valid int value
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### hasNextInt

          public boolean hasNextInt(int radix)

      Returns true if the next token in this scanner's input can be interpreted as an int value in the specified radix using the `nextInt()` method. The scanner does not advance past any input.
      Parameters:
        `radix` - the radix used to interpret the token as an int value
      Returns:
        true if and only if this scanner's next token is a valid int value
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### nextInt

          public int nextInt()

      Scans the next token of the input as an `int`.

      An invocation of this method of the form `nextInt()` behaves in exactly the same way as the invocation `nextInt(radix)`, where `radix` is the default radix of this scanner.

      Returns:
        the `int` scanned from the input
      Throws:
        `InputMismatchException` - if the next token does not match the Integer regular expression, or is out of range
        `NoSuchElementException` - if input is exhausted
        `IllegalStateException` - if this scanner is closed

    - #### nextInt

          public int nextInt(int radix)

      Scans the next token of the input as an `int`. This method will throw `InputMismatchException` if the next token cannot be translated into a valid int value as described below. If the translation is successful, the scanner advances past the input that matched.

      If the next token matches the Integer regular expression defined above then the token is converted into an `int` value as if by removing all locale specific prefixes, group separators, and locale specific suffixes, then mapping non-ASCII digits into ASCII digits via `Character.digit`, prepending a negative sign (-) if the locale specific negative prefixes and suffixes were present, and passing the resulting string to `Integer.parseInt` with the specified radix.

      Parameters:
        `radix` - the radix used to interpret the token as an int value
      Returns:
        the `int` scanned from the input
      Throws:
        `InputMismatchException` - if the next token does not match the Integer regular expression, or is out of range
        `NoSuchElementException` - if input is exhausted
        `IllegalStateException` - if this scanner is closed

    - #### hasNextLong

          public boolean hasNextLong()

      Returns true if the next token in this scanner's input can be interpreted as a long value in the default radix using the `nextLong()` method. The scanner does not advance past any input.
      Returns:
        true if and only if this scanner's next token is a valid long value
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### hasNextLong

          public boolean hasNextLong(int radix)

      Returns true if the next token in this scanner's input can be interpreted as a long value in the specified radix using the `nextLong()` method. The scanner does not advance past any input.
      Parameters:
        `radix` - the radix used to interpret the token as a long value
      Returns:
        true if and only if this scanner's next token is a valid long value
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### nextLong

          public long nextLong()

      Scans the next token of the input as a `long`.

      An invocation of this method of the form `nextLong()` behaves in exactly the same way as the invocation `nextLong(radix)`, where `radix` is the default radix of this scanner.

      Returns:
        the `long` scanned from the input
      Throws:
        `InputMismatchException` - if the next token does not match the Integer regular expression, or is out of range
        `NoSuchElementException` - if input is exhausted
        `IllegalStateException` - if this scanner is closed

    - #### nextLong

          public long nextLong(int radix)

      Scans the next token of the input as a `long`. This method will throw `InputMismatchException` if the next token cannot be translated into a valid long value as described below. If the translation is successful, the scanner advances past the input that matched.

      If the next token matches the Integer regular expression defined above then the token is converted into a `long` value as if by removing all locale specific prefixes, group separators, and locale specific suffixes, then mapping non-ASCII digits into ASCII digits via `Character.digit`, prepending a negative sign (-) if the locale specific negative prefixes and suffixes were present, and passing the resulting string to `Long.parseLong` with the specified radix.

      Parameters:
        `radix` - the radix used to interpret the token as an int value
      Returns:
        the `long` scanned from the input
      Throws:
        `InputMismatchException` - if the next token does not match the Integer regular expression, or is out of range
        `NoSuchElementException` - if input is exhausted
        `IllegalStateException` - if this scanner is closed

    - #### hasNextFloat

          public boolean hasNextFloat()

      Returns true if the next token in this scanner's input can be interpreted as a float value using the `nextFloat()` method. The scanner does not advance past any input.
      Returns:
        true if and only if this scanner's next token is a valid float value
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### nextFloat

          public float nextFloat()

      Scans the next token of the input as a `float`. This method will throw `InputMismatchException` if the next token cannot be translated into a valid float value as described below. If the translation is successful, the scanner advances past the input that matched.

      If the next token matches the Float regular expression defined above then the token is converted into a `float` value as if by removing all locale specific prefixes, group separators, and locale specific suffixes, then mapping non-ASCII digits into ASCII digits via `Character.digit`, prepending a negative sign (-) if the locale specific negative prefixes and suffixes were present, and passing the resulting string to `Float.parseFloat`. If the token matches the localized NaN or infinity strings, then either "Nan" or "Infinity" is passed to `Float.parseFloat` as appropriate.

      Returns:
        the `float` scanned from the input
      Throws:
        `InputMismatchException` - if the next token does not match the Float regular expression, or is out of range
        `NoSuchElementException` - if input is exhausted
        `IllegalStateException` - if this scanner is closed

    - #### hasNextDouble

          public boolean hasNextDouble()

      Returns true if the next token in this scanner's input can be interpreted as a double value using the `nextDouble()` method. The scanner does not advance past any input.
      Returns:
        true if and only if this scanner's next token is a valid double value
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### nextDouble

          public double nextDouble()

      Scans the next token of the input as a `double`. This method will throw `InputMismatchException` if the next token cannot be translated into a valid double value. If the translation is successful, the scanner advances past the input that matched.

      If the next token matches the Float regular expression defined above then the token is converted into a `double` value as if by removing all locale specific prefixes, group separators, and locale specific suffixes, then mapping non-ASCII digits into ASCII digits via `Character.digit`, prepending a negative sign (-) if the locale specific negative prefixes and suffixes were present, and passing the resulting string to `Double.parseDouble`. If the token matches the localized NaN or infinity strings, then either "Nan" or "Infinity" is passed to `Double.parseDouble` as appropriate.

      Returns:
        the `double` scanned from the input
      Throws:
        `InputMismatchException` - if the next token does not match the Float regular expression, or is out of range
        `NoSuchElementException` - if the input is exhausted
        `IllegalStateException` - if this scanner is closed

    - #### hasNextBigInteger

          public boolean hasNextBigInteger()

      Returns true if the next token in this scanner's input can be interpreted as a `BigInteger` in the default radix using the `nextBigInteger()` method. The scanner does not advance past any input.
      Returns:
        true if and only if this scanner's next token is a valid `BigInteger`
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### hasNextBigInteger

          public boolean hasNextBigInteger(int radix)

      Returns true if the next token in this scanner's input can be interpreted as a `BigInteger` in the specified radix using the `nextBigInteger()` method. The scanner does not advance past any input.
      Parameters:
        `radix` - the radix used to interpret the token as an integer
      Returns:
        true if and only if this scanner's next token is a valid `BigInteger`
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### nextBigInteger

          public BigInteger nextBigInteger()

      Scans the next token of the input as a `BigInteger`.

      An invocation of this method of the form `nextBigInteger()` behaves in exactly the same way as the invocation `nextBigInteger(radix)`, where `radix` is the default radix of this scanner.

      Returns:
        the `BigInteger` scanned from the input
      Throws:
        `InputMismatchException` - if the next token does not match the Integer regular expression, or is out of range
        `NoSuchElementException` - if the input is exhausted
        `IllegalStateException` - if this scanner is closed

    - #### nextBigInteger

          public BigInteger nextBigInteger(int radix)

      Scans the next token of the input as a `BigInteger`.

      If the next token matches the Integer regular expression defined above then the token is converted into a `BigInteger` value as if by removing all group separators, mapping non-ASCII digits into ASCII digits via the `Character.digit`, and passing the resulting string to the `BigInteger(String, int)` constructor with the specified radix.

      Parameters:
        `radix` - the radix used to interpret the token
      Returns:
        the `BigInteger` scanned from the input
      Throws:
        `InputMismatchException` - if the next token does not match the Integer regular expression, or is out of range
        `NoSuchElementException` - if the input is exhausted
        `IllegalStateException` - if this scanner is closed

    - #### hasNextBigDecimal

          public boolean hasNextBigDecimal()

      Returns true if the next token in this scanner's input can be interpreted as a `BigDecimal` using the `nextBigDecimal()` method. The scanner does not advance past any input.
      Returns:
        true if and only if this scanner's next token is a valid `BigDecimal`
      Throws:
        `IllegalStateException` - if this scanner is closed

    - #### nextBigDecimal

          public BigDecimal nextBigDecimal()

      Scans the next token of the input as a `BigDecimal`.

      If the next token matches the Decimal regular expression defined above then the token is converted into a `BigDecimal` value as if by removing all group separators, mapping non-ASCII digits into ASCII digits via the `Character.digit`, and passing the resulting string to the `BigDecimal(String)` constructor.

      Returns:
        the `BigDecimal` scanned from the input
      Throws:
        `InputMismatchException` - if the next token does not match the Decimal regular expression, or is out of range
        `NoSuchElementException` - if the input is exhausted
        `IllegalStateException` - if this scanner is closed

    - #### reset

          public Scanner reset()

      Resets this scanner.

      Resetting a scanner discards all of its explicit state information which may have been changed by invocations of `useDelimiter(java.util.regex.Pattern)`, `useLocale(java.util.Locale)`, or `useRadix(int)`.

      An invocation of this method of the form `scanner.reset()` behaves in exactly the same way as the invocation

      >        scanner.useDelimiter("\\p{javaWhitespace}+")
      >               .useLocale(Locale.getDefault())
      >               .useRadix(10);

      Returns:
        this scanner
      Since:
        1.6

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