Java IO.pdf - Nguyen Dang Binh

Java I/O
The isWhitespace() method returns true if a character is a Unicode space separator
character other than a nonbreaking space (160 and 65,279). It also returns true if the
specified character is a line separator, a paragraph separator, a horizontal tab (\t, ASCII 9), a
vertical tab (ASCII 11), a formfeed (ASCII 12), a carriage return (\r, ASCII 13), a linefeed
(\n, ASCII 10), a file separator (ASCII 28), a group separator (ASCII 29), a record separator
(ASCII 30), or a unit separator (ASCII 31).
public static boolean isWhitespace(char ch)
The isSpace() method is a less accurate version of isWhitespace() held over from Java
1.0. It returns true if its argument is a carriage return, linefeed, horizontal tab, formfeed, or
ASCII space. Otherwise, it returns false. It's deprecated and should not be used in new code.
public static boolean isSpace(char c)
The isISOControl() method returns true if the specified character is an ISO Latin-1 control
character; in other words, if it's in the range to 31 or 127 to 159.
public static boolean isISOControl(char c)
14.5.1.4 Identifiers
Until Java, most programming languages were explicitly based on ASCII. Identifiers—e.g.,
variable names, class names, method names, and so forth—were defined as being composed
of some particular subset of these characters, generally allowing alphanumeric characters and
some punctuation marks like the underscore but excluding the rest of ASCII. Furthermore,
some languages distinguish between characters allowed in the middle of an identifier and
characters that may start an identifier.
The Unicode standard makes some suggestions for which Unicode characters should be
allowed in programming language identifiers. Generally, all the alphanumeric characters from
any script as well as certain joining characters and bidirectional indicators are allowed in
identifiers, while most other characters are not. However, programming language designers
are free to accept or reject the Unicode standard's suggestions in these matters.
Character.isUnicodeIdentifierStart() returns true if the specified character may be
the first character of an identifier; that is, if it is a Unicode letter.
Character.isUnicodeIdentifierPart() returns true if the specified character may be
part of the interior of a Unicode identifier; that is, the specified character is a letter, a digit, a
numeric letter like a Roman numeral, a combining mark, an underscore, a nonspacing mark,
or an ignorable control character.
public static boolean isUnicodeIdentifierStart(char c)
public static boolean isUnicodeIdentifierPart(char c)
Java's identifier syntax is not exactly the same as the Unicode identifier syntax, though they
are similar; the Java identifier characters are a superset of the Unicode identifier characters.
As well as the Unicode identifier characters, Java identifiers include currency symbols ($, £,
¢, ¥, , the Bengali rupee sign, the Thai currency symbol baht, the EC sign, the colon sign,
the cruzeiro sign, the French franc sign, the lira sign, the mill sign, the naira sign, the peseta
sign, the Indian rupee sign, the won sign, the new shekel sign, the dong sign, etc.). Java start
identifiers also include the connecting punctuation characters underscore, undertie, character
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