@GwtCompatible public final class Ascii extends Object
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.
Modifier and Type | Field and Description |
---|---|
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.
|
Modifier and Type | Method and Description |
---|---|
static boolean |
equalsIgnoreCase(CharSequence s1,
CharSequence s2)
Indicates whether the contents of the given character sequences
s1 and s2 are
equal, ignoring the case of any ASCII alphabetic characters between 'a' and 'z'
or 'A' and 'Z' inclusive. |
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(CharSequence chars)
Returns a copy of the input character sequence in which all uppercase ASCII characters have been converted to lowercase.
|
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(CharSequence chars)
Returns a copy of the input character sequence in which all lowercase ASCII characters have been converted to uppercase.
|
static String |
toUpperCase(String string)
Returns a copy of the input string in which all lowercase ASCII
characters have been converted to uppercase.
|
static String |
truncate(CharSequence seq,
int maxLength,
String truncationIndicator)
Truncates the given character sequence to the given maximum length.
|
public static final byte NUL
Although RFC 20 names this as "Null", note that it is distinct from the C/C++ "NULL" pointer.
public static final byte SOH
public static final byte STX
public static final byte ETX
public static final byte EOT
public static final byte ENQ
public static final byte ACK
public static final byte BEL
public static final byte BS
public static final byte HT
public static final byte LF
public static final byte NL
LF
. (LF
is preferred.)public static final byte VT
public static final byte FF
public static final byte CR
public static final byte SO
public static final byte SI
public static final byte DLE
public static final byte DC1
public static final byte XON
public static final byte DC2
public static final byte DC3
public static final byte XOFF
XON
for explanation.public static final byte DC4
public static final byte NAK
public static final byte SYN
public static final byte ETB
public static final byte CAN
public static final byte EM
public static final byte SUB
public static final byte ESC
public static final byte FS
public static final byte GS
public static final byte RS
public static final byte US
public static final byte SP
public static final byte SPACE
SP
.public static final byte DEL
public static final char MIN
int
before 12.0)public static final char MAX
int
before 12.0)public static String toLowerCase(String string)
public static String toLowerCase(CharSequence chars)
public static char toLowerCase(char c)
public static String toUpperCase(String string)
public static String toUpperCase(CharSequence chars)
public static char toUpperCase(char c)
public static boolean isLowerCase(char c)
c
is one of the twenty-six lowercase ASCII alphabetic characters
between 'a'
and 'z'
inclusive. All others (including non-ASCII characters)
return false
.public static boolean isUpperCase(char c)
c
is one of the twenty-six uppercase ASCII alphabetic characters
between 'A'
and 'Z'
inclusive. All others (including non-ASCII characters)
return false
.public static String truncate(CharSequence seq, int maxLength, String truncationIndicator)
maxLength
, the returned string will be exactly maxLength
chars in length and will end with the given truncationIndicator
. Otherwise,
the sequence will be returned as a string with no changes to the content.
Examples:
Ascii.truncate("foobar", 7, "..."); // returns "foobar"
Ascii.truncate("foobar", 5, "..."); // returns "fo..."
Note: This method may work with certain non-ASCII text but is not safe for use with arbitrary Unicode text. It is mostly intended for use with text that is known to be safe for use with it (such as all-ASCII text) and for simple debugging text. When using this method, consider the following:
IllegalArgumentException
- if maxLength
is less than the length of truncationIndicator
public static boolean equalsIgnoreCase(CharSequence s1, CharSequence s2)
s1
and s2
are
equal, ignoring the case of any ASCII alphabetic characters between 'a'
and 'z'
or 'A'
and 'Z'
inclusive.
This method is significantly faster than String.equalsIgnoreCase(java.lang.String)
and should be used
in preference if at least one of the parameters is known to contain only ASCII characters.
Note however that this method does not always behave identically to expressions such as:
string.toUpperCase().equals("UPPER CASE ASCII")
string.toLowerCase().equals("lower case ascii")
due to case-folding of some non-ASCII characters (which does not occur in String.equalsIgnoreCase(java.lang.String)
). However in almost all cases that ASCII strings are used, the author
probably wanted the behavior provided by this method rather than the subtle and sometimes
surprising behavior of toUpperCase()
and toLowerCase()
.
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