## com.google.common.base
Class Ascii

    java.lang.Object
      com.google.common.base.Ascii

    @GwtCompatible
    public final class Ascii

extends Object

Static methods pertaining to ASCII characters (those in the range of values `0x00` through `0x7F`), and to strings containing such characters.

ASCII utilities also exist in other classes of this package:

- `Charsets.US_ASCII` specifies the `Charset` of ASCII characters.
- `CharMatcher.ASCII` matches ASCII characters and provides text processing methods which operate only on the ASCII characters of a string.

Since:
  7.0
Author:
  Craig Berry, Gregory Kick

Field Summary
`static byte` `ACK` Acknowledge: A communication control character transmitted by a receiver as an affirmative response to a sender.
`static byte` `BEL` Bell ('\a'): A character for use when there is a need to call for human attention.
`static byte` `BS` Backspace ('\b'): A format effector which controls the movement of the printing position one printing space backward on the same printing line.
`static byte` `CAN` Cancel: A control character used to indicate that the data with which it is sent is in error or is to be disregarded.
`static byte` `CR` Carriage Return ('\r'): A format effector which controls the movement of the printing position to the first printing position on the same printing line.
`static byte` `DC1` Device Control 1.
`static byte` `DC2` Device Control 2.
`static byte` `DC3` Device Control 3.
`static byte` `DC4` Device Control 4.
`static byte` `DEL` Delete: This character is used primarily to "erase" or "obliterate" erroneous or unwanted characters in perforated tape.
`static byte` `DLE` Data Link Escape: A communication control character which will change the meaning of a limited number of contiguously following characters.
`static byte` `EM` End of Medium: A control character associated with the sent data which may be used to identify the physical end of the medium, or the end of the used, or wanted, portion of information recorded on a medium.
`static byte` `ENQ` Enquiry: A communication control character used in data communication systems as a request for a response from a remote station.
`static byte` `EOT` End of Transmission: A communication control character used to indicate the conclusion of a transmission, which may have contained one or more texts and any associated headings.
`static byte` `ESC` Escape: A control character intended to provide code extension (supplementary characters) in general information interchange.
`static byte` `ETB` End of Transmission Block: A communication control character used to indicate the end of a block of data for communication purposes.
`static byte` `ETX` End of Text: A communication control character used to terminate a sequence of characters started with STX and transmitted as an entity.
`static byte` `FF` Form Feed ('\f'): A format effector which controls the movement of the printing position to the first pre-determined printing line on the next form or page.
`static byte` `FS` File Separator: These four information separators may be used within data in optional fashion, except that their hierarchical relationship shall be: FS is the most inclusive, then GS, then RS, and US is least inclusive.
`static byte` `GS` Group Separator: These four information separators may be used within data in optional fashion, except that their hierarchical relationship shall be: FS is the most inclusive, then GS, then RS, and US is least inclusive.
`static byte` `HT` Horizontal Tabulation ('\t'): A format effector which controls the movement of the printing position to the next in a series of predetermined positions along the printing line.
`static byte` `LF` Line Feed ('\n'): A format effector which controls the movement of the printing position to the next printing line.
`static char` `MAX` The maximum value of an ASCII character.
`static char` `MIN` The minimum value of an ASCII character.
`static byte` `NAK` Negative Acknowledge: A communication control character transmitted by a receiver as a negative response to the sender.
`static byte` `NL` Alternate name for `LF`.
`static byte` `NUL` Null ('\0'): The all-zeros character which may serve to accomplish time fill and media fill.
`static byte` `RS` Record Separator: These four information separators may be used within data in optional fashion, except that their hierarchical relationship shall be: FS is the most inclusive, then GS, then RS, and US is least inclusive.
`static byte` `SI` Shift In: A control character indicating that the code combinations which follow shall be interpreted according to the standard code table.
`static byte` `SO` Shift Out: A control character indicating that the code combinations which follow shall be interpreted as outside of the character set of the standard code table until a Shift In character is reached.
`static byte` `SOH` Start of Heading: A communication control character used at the beginning of a sequence of characters which constitute a machine-sensible address or routing information.
`static byte` `SP` Space: A normally non-printing graphic character used to separate words.
`static byte` `SPACE` Alternate name for `SP`.
`static byte` `STX` Start of Text: A communication control character which precedes a sequence of characters that is to be treated as an entity and entirely transmitted through to the ultimate destination.
`static byte` `SUB` Substitute: A character that may be substituted for a character which is determined to be invalid or in error.
`static byte` `SYN` Synchronous Idle: A communication control character used by a synchronous transmission system in the absence of any other character to provide a signal from which synchronism may be achieved or retained.
`static byte` `US` Unit Separator: These four information separators may be used within data in optional fashion, except that their hierarchical relationship shall be: FS is the most inclusive, then GS, then RS, and US is least inclusive.
`static byte` `VT` Vertical Tabulation ('\v'): A format effector which controls the movement of the printing position to the next in a series of predetermined printing lines.
`static byte` `XOFF` Transmission off.
`static byte` `XON` Transmission On: Although originally defined as DC1, this ASCII control character is now better known as the XON code used for software flow control in serial communications.

Method Summary
`static boolean` `isLowerCase(char c)` Indicates whether `c` is one of the twenty-six lowercase ASCII alphabetic characters between `'a'` and `'z'` inclusive.
`static boolean` `isUpperCase(char c)` Indicates whether `c` is one of the twenty-six uppercase ASCII alphabetic characters between `'A'` and `'Z'` inclusive.
`static char` `toLowerCase(char c)` If the argument is an uppercase ASCII character returns the lowercase equivalent.
`static String` `toLowerCase(String string)` Returns a copy of the input string in which all uppercase ASCII characters have been converted to lowercase.
`static char` `toUpperCase(char c)` If the argument is a lowercase ASCII character returns the uppercase equivalent.
`static String` `toUpperCase(String string)` Returns a copy of the input string in which all lowercase ASCII characters have been converted to uppercase.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

### NUL

    public static final byte NUL

  Null ('\0'): The all-zeros character which may serve to accomplish time fill and media fill. Normally used as a C string terminator.

  Although RFC 20 names this as "Null", note that it is distinct from the C/C++ "NULL" pointer.

  Since:
    8.0
  See Also:
    Constant Field Values

### SOH

    public static final byte SOH

  Start of Heading: A communication control character used at the beginning of a sequence of characters which constitute a machine-sensible address or routing information. Such a sequence is referred to as the "heading." An STX character has the effect of terminating a heading.

  Since:
    8.0
  See Also:
    Constant Field Values

### STX

    public static final byte STX

  Start of Text: A communication control character which precedes a sequence of characters that is to be treated as an entity and entirely transmitted through to the ultimate destination. Such a sequence is referred to as "text." STX may be used to terminate a sequence of characters started by SOH.

  Since:
    8.0
  See Also:
    Constant Field Values

### ETX

    public static final byte ETX

  End of Text: A communication control character used to terminate a sequence of characters started with STX and transmitted as an entity.

  Since:
    8.0
  See Also:
    Constant Field Values

### EOT

    public static final byte EOT

  End of Transmission: A communication control character used to indicate the conclusion of a transmission, which may have contained one or more texts and any associated headings.

  Since:
    8.0
  See Also:
    Constant Field Values

### ENQ

    public static final byte ENQ

  Enquiry: A communication control character used in data communication systems as a request for a response from a remote station. It may be used as a "Who Are You" (WRU) to obtain identification, or may be used to obtain station status, or both.

  Since:
    8.0
  See Also:
    Constant Field Values

### ACK

    public static final byte ACK

  Acknowledge: A communication control character transmitted by a receiver as an affirmative response to a sender.

  Since:
    8.0
  See Also:
    Constant Field Values

### BEL

    public static final byte BEL

  Bell ('\a'): A character for use when there is a need to call for human attention. It may control alarm or attention devices.

  Since:
    8.0
  See Also:
    Constant Field Values

### BS

    public static final byte BS

  Backspace ('\b'): A format effector which controls the movement of the printing position one printing space backward on the same printing line. (Applicable also to display devices.)

  Since:
    8.0
  See Also:
    Constant Field Values

### HT

    public static final byte HT

  Horizontal Tabulation ('\t'): A format effector which controls the movement of the printing position to the next in a series of predetermined positions along the printing line. (Applicable also to display devices and the skip function on punched cards.)

  Since:
    8.0
  See Also:
    Constant Field Values

### LF

    public static final byte LF

  Line Feed ('\n'): A format effector which controls the movement of the printing position to the next printing line. (Applicable also to display devices.) Where appropriate, this character may have the meaning "New Line" (NL), a format effector which controls the movement of the printing point to the first printing position on the next printing line. Use of this convention requires agreement between sender and recipient of data.

  Since:
    8.0
  See Also:
    Constant Field Values

### NL

    public static final byte NL

  Alternate name for `LF`. (`LF` is preferred.)

  Since:
    8.0
  See Also:
    Constant Field Values

### VT

    public static final byte VT

  Vertical Tabulation ('\v'): A format effector which controls the movement of the printing position to the next in a series of predetermined printing lines. (Applicable also to display devices.)

  Since:
    8.0
  See Also:
    Constant Field Values

### FF

    public static final byte FF

  Form Feed ('\f'): A format effector which controls the movement of the printing position to the first pre-determined printing line on the next form or page. (Applicable also to display devices.)

  Since:
    8.0
  See Also:
    Constant Field Values

### CR

    public static final byte CR

  Carriage Return ('\r'): A format effector which controls the movement of the printing position to the first printing position on the same printing line. (Applicable also to display devices.)

  Since:
    8.0
  See Also:
    Constant Field Values

### SO

    public static final byte SO

  Shift Out: A control character indicating that the code combinations which follow shall be interpreted as outside of the character set of the standard code table until a Shift In character is reached.

  Since:
    8.0
  See Also:
    Constant Field Values

### SI

    public static final byte SI

  Shift In: A control character indicating that the code combinations which follow shall be interpreted according to the standard code table.

  Since:
    8.0
  See Also:
    Constant Field Values

### DLE

    public static final byte DLE

  Data Link Escape: A communication control character which will change the meaning of a limited number of contiguously following characters. It is used exclusively to provide supplementary controls in data communication networks.

  Since:
    8.0
  See Also:
    Constant Field Values

### DC1

    public static final byte DC1

  Device Control 1. Characters for the control of ancillary devices associated with data processing or telecommunication systems, more especially switching devices "on" or "off." (If a single "stop" control is required to interrupt or turn off ancillary devices, DC4 is the preferred assignment.)

  Since:
    8.0
  See Also:
    Constant Field Values

### XON

    public static final byte XON

  Transmission On: Although originally defined as DC1, this ASCII control character is now better known as the XON code used for software flow control in serial communications. The main use is restarting the transmission after the communication has been stopped by the XOFF control code.

  Since:
    8.0
  See Also:
    Constant Field Values

### DC2

    public static final byte DC2

  Device Control 2. Characters for the control of ancillary devices associated with data processing or telecommunication systems, more especially switching devices "on" or "off." (If a single "stop" control is required to interrupt or turn off ancillary devices, DC4 is the preferred assignment.)

  Since:
    8.0
  See Also:
    Constant Field Values

### DC3

    public static final byte DC3

  Device Control 3. Characters for the control of ancillary devices associated with data processing or telecommunication systems, more especially switching devices "on" or "off." (If a single "stop" control is required to interrupt or turn off ancillary devices, DC4 is the preferred assignment.)

  Since:
    8.0
  See Also:
    Constant Field Values

### XOFF

    public static final byte XOFF

  Transmission off. See `XON` for explanation.

  Since:
    8.0
  See Also:
    Constant Field Values

### DC4

    public static final byte DC4

  Device Control 4. Characters for the control of ancillary devices associated with data processing or telecommunication systems, more especially switching devices "on" or "off." (If a single "stop" control is required to interrupt or turn off ancillary devices, DC4 is the preferred assignment.)

  Since:
    8.0
  See Also:
    Constant Field Values

### NAK

    public static final byte NAK

  Negative Acknowledge: A communication control character transmitted by a receiver as a negative response to the sender.

  Since:
    8.0
  See Also:
    Constant Field Values

### SYN

    public static final byte SYN

  Synchronous Idle: A communication control character used by a synchronous transmission system in the absence of any other character to provide a signal from which synchronism may be achieved or retained.

  Since:
    8.0
  See Also:
    Constant Field Values

### ETB

    public static final byte ETB

  End of Transmission Block: A communication control character used to indicate the end of a block of data for communication purposes. ETB is used for blocking data where the block structure is not necessarily related to the processing format.

  Since:
    8.0
  See Also:
    Constant Field Values

### CAN

    public static final byte CAN

  Cancel: A control character used to indicate that the data with which it is sent is in error or is to be disregarded.

  Since:
    8.0
  See Also:
    Constant Field Values

### EM

    public static final byte EM

  End of Medium: A control character associated with the sent data which may be used to identify the physical end of the medium, or the end of the used, or wanted, portion of information recorded on a medium. (The position of this character does not necessarily correspond to the physical end of the medium.)

  Since:
    8.0
  See Also:
    Constant Field Values

### SUB

    public static final byte SUB

  Substitute: A character that may be substituted for a character which is determined to be invalid or in error.

  Since:
    8.0
  See Also:
    Constant Field Values

### ESC

    public static final byte ESC

  Escape: A control character intended to provide code extension (supplementary characters) in general information interchange. The Escape character itself is a prefix affecting the interpretation of a limited number of contiguously following characters.

  Since:
    8.0
  See Also:
    Constant Field Values

### FS

    public static final byte FS

  File Separator: These four information separators may be used within data in optional fashion, except that their hierarchical relationship shall be: FS is the most inclusive, then GS, then RS, and US is least inclusive. (The content and length of a File, Group, Record, or Unit are not specified.)

  Since:
    8.0
  See Also:
    Constant Field Values

### GS

    public static final byte GS

  Group Separator: These four information separators may be used within data in optional fashion, except that their hierarchical relationship shall be: FS is the most inclusive, then GS, then RS, and US is least inclusive. (The content and length of a File, Group, Record, or Unit are not specified.)

  Since:
    8.0
  See Also:
    Constant Field Values

### RS

    public static final byte RS

  Record Separator: These four information separators may be used within data in optional fashion, except that their hierarchical relationship shall be: FS is the most inclusive, then GS, then RS, and US is least inclusive. (The content and length of a File, Group, Record, or Unit are not specified.)

  Since:
    8.0
  See Also:
    Constant Field Values

### US

    public static final byte US

  Unit Separator: These four information separators may be used within data in optional fashion, except that their hierarchical relationship shall be: FS is the most inclusive, then GS, then RS, and US is least inclusive. (The content and length of a File, Group, Record, or Unit are not specified.)

  Since:
    8.0
  See Also:
    Constant Field Values

### SP

    public static final byte SP

  Space: A normally non-printing graphic character used to separate words. It is also a format effector which controls the movement of the printing position, one printing position forward. (Applicable also to display devices.)

  Since:
    8.0
  See Also:
    Constant Field Values

### SPACE

    public static final byte SPACE

  Alternate name for `SP`.

  Since:
    8.0
  See Also:
    Constant Field Values

### DEL

    public static final byte DEL

  Delete: This character is used primarily to "erase" or "obliterate" erroneous or unwanted characters in perforated tape.

  Since:
    8.0
  See Also:
    Constant Field Values

### MIN

    public static final char MIN

  The minimum value of an ASCII character.

  Since:
    9.0 (was type `int` before 12.0)
  See Also:
    Constant Field Values

### MAX

    public static final char MAX

  The maximum value of an ASCII character.

  Since:
    9.0 (was type `int` before 12.0)
  See Also:
    Constant Field Values

Method Detail

### toLowerCase

    public static String toLowerCase(String string)

  Returns a copy of the input string in which all uppercase ASCII characters have been converted to lowercase. All other characters are copied without modification.

### toLowerCase

    public static char toLowerCase(char c)

  If the argument is an uppercase ASCII character returns the lowercase equivalent. Otherwise returns the argument.

### toUpperCase

    public static String toUpperCase(String string)

  Returns a copy of the input string in which all lowercase ASCII characters have been converted to uppercase. All other characters are copied without modification.

### toUpperCase

    public static char toUpperCase(char c)

  If the argument is a lowercase ASCII character returns the uppercase equivalent. Otherwise returns the argument.

### isLowerCase

    public static boolean isLowerCase(char c)

  Indicates whether `c` is one of the twenty-six lowercase ASCII alphabetic characters between `'a'` and `'z'` inclusive. All others (including non-ASCII characters) return `false`.

### isUpperCase

    public static boolean isUpperCase(char c)

  Indicates whether `c` is one of the twenty-six uppercase ASCII alphabetic characters between `'A'` and `'Z'` inclusive. All others (including non-ASCII characters) return `false`.

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