Java Reference
In-Depth Information
P
A
Operator
Operand type(s)
Operation performed
+=
,
-=
,
<<=
,
>>=
,
>>>=
,
&=
,
^=
,
|=
1
R
→
arglist, method body
lambda expression
Operand number and type
The fourth column of
Table 2-4
specifies the number and type of the operands
expected by each operator. Some operators operate on only one operand; these are
called unary operators. For example, the unary minus operator changes the sign of a
single number:
-
n
// The unary minus operator
Most operators, however, are binary operators that operate on two operand values.
The
-
operator actually comes in both forms:
a
-
b
// The subtraction operator is a binary operator
Java also defines one ternary operator, often called the conditional operator. It is like
an
if
statement inside an expression. Its three operands are separated by a question
mark and a colon; the second and third operands must be convertible to the same
type:
x
>
y
?
x
:
y
// Ternary expression; evaluates to larger of x and y
In addition to expecting a certain number of operands, each operator also expects
particular types of operands. The fourth column of the table lists the operand types.
Some of the codes used in that column require further explanation:
Number
An integer, floating-point value, or character (i.e., any primitive type except
boolean
). Autounboxing (see
“Boxing and Unboxing Conversions” on page 87
)
means that the wrapper classes (such as
Character
,
Integer
, and
Double
) for
these types can be used in this context as well.
Integer
A
byte
,
short
,
int
,
long
, or
char
value (
long
values are not allowed for the
array access operator
[ ]
). With autounboxing,
Byte
,
Short
,
Integer
,
Long
,
and
Character
values are also allowed.
Reference
An object or array.
