Indice
grammatica
Commenti |
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|
Letterali |
|
number |
Type int |
number[l | L] |
Type long |
0xhex |
Hex integer |
0Xhex |
Hex integer |
0octal |
Octal integer |
[ number ].number |
Type double |
number[ f | f] |
Type float |
number[ d | D] |
Type double |
[ + | - ] number |
Signed |
numberenumber |
Exponent |
numberEnumber |
Exponent |
‘character’ |
Single character |
“characters” |
String |
“” |
Empty string |
\b |
Backspace |
\t |
Tab |
\n |
Line feed |
\f |
Form feed |
\r |
Carriage return |
\” |
Double quote |
\’ |
Single quote |
\\ |
Backslash |
\uNNNN |
Unicode escape (NNNN is hex) |
true |
Boolean |
false |
Boolean |
Dichiarazione
di Variabili |
|
[ byte | short | int |
long ] varname |
Integers |
[ float | double ] varname |
Floats |
char varname |
Characters |
boolean varname |
Boolean |
classname varname |
Class types |
interfacename varname |
Interface types |
type varname1,
varname2, varname3 |
Multiple variables |
Le
seguenti opzioni sono disponibili solo per
variabili
istanza e di classe |
|
[ static ] variableDeclaration |
Class variable |
[ final ] variableDeclaration |
Constants |
[ public | private | protected
] variableDeclaration |
Access control |
[volatile] varname |
Modified asynchro-nously |
[transient] varname |
Not persistent |
Assegnamento |
|
variable = value |
Assignment |
variable++ |
Postfix Increment |
++variable |
Prefix Increment |
variable– – |
Postfix Decrement |
– –variable |
Prefix Decrement |
variable += value |
Add and assign |
variable –= value |
Subtract and assign |
variable *= value |
Multiply and assign |
variable /= value |
Divide and assign |
variable %= value |
Modulus and assign |
variable &= value |
AND and assign |
variable |= value |
OR and assign |
variable ^= value |
XOR and assign |
variable <<= value |
Left-shift and assign |
variable >>= value |
Right-shift and assign |
variable >>>= value |
Zero-fill right-shift and assign |
Operatori |
|
arg + arg |
Addition |
arg – arg |
Subtraction |
arg * arg |
Multiplication |
arg / arg |
Division |
arg % arg |
Modulus |
arg < arg |
Less than |
arg > arg |
Greater than |
arg <= arg |
Less than or equal to |
arg >= arg |
Greater than or equal to |
arg = = arg |
Equal |
arg != arg |
Not equal |
arg && arg |
Logical AND |
arg || arg |
Logical OR |
! arg |
Logical NOT |
arg & arg |
AND |
arg | arg |
OR |
arg ^ arg |
XOR |
arg << arg |
Left-shift |
arg >> arg |
Right-shift |
arg >>> arg |
Zero-fill right-shift |
~ arg |
Complement |
(type)thing |
Casting |
arg instanceof class |
Instance of |
test ? trueOp : falseOp |
Tenary (if) operator |
Oggetti |
|
new class() |
Create new instance |
new class(arg1, arg2, arg3, ...) |
New instance with parameters |
object.variable |
Instance variable |
object.classvar |
Class variable |
object.method() |
Instance method (no args) |
object.method(arg1, arg2, arg3, ...) |
Instance method |
object.classmethod() |
Class method (no args) |
object.classmethod(arg1 ,arg2 ,arg3,
...) |
Class method |
Class.classmethod() |
Class method (no args) |
Class.classmethod(arg1, arg2, arg3,
...) |
Class method |
Array |
|
type varname[] |
Array variable |
type[] varname |
Array variable |
new type[numElements] |
New array object |
array[index] |
Element access |
array.length |
Length of array |
Cicli
e istruz. condizionali |
|
if ( test) block |
Conditional |
if ( test ) block
else block |
Conditional with else |
switch (test) {
case value : statements
[break]
case value : statements
[break]
...
default : statement
} |
switch (only with integer or
char types) |
for (initializer; test; change ) block |
for loop |
while ( test ) block |
while loop |
do block
while (test) |
do loop |
break [ label ] |
break from loop or switch |
continue [ label ] |
continue loops |
label: |
Labeled loops |
Definizione
di Classi |
|
class classname block |
Simple Class definition |
[ final ] class classname block |
Class cannot be subclassed |
[ abstract ] class classname block |
Class cannot be instantiated |
[ public ] class classname block |
Class accessible outside package |
class classname [ extends Superclass
] block |
Extends superclass |
class classname [ implements interfaces
] block |
Implement one or more
interfaces |
Metodi
e Costruttori |
|
returnType methodName() block |
Basic method |
returnType methodName(parameter, parameter,
...) block |
Method with parametersMethod with
parameters |
[ abstract ] returnType methodName()
block |
Abstract method |
[ static ] returnType methodName()
block |
Class method |
[ native ] returnType methodName()
block |
Native method |
[ final ] returnType methodName()
block |
Ifinal method |
[ synchronized ] returnType methodName()
block |
Thread lock before executing |
[ public | private | protected ] returnType
methodName() block |
Access control |
super.methodName() |
Call a superclass’s method |
classname() block |
basic constructor |
classname(parameter, parameter, parameter...)
block |
constructor with parameters |
[ public | private | protected] classname()
block |
Access control |
this(...) |
Calls class’s constructor |
super(...) |
Calls superclass’s constructor |
Package
e Interfacce |
|
import package.className |
Imports specific class name |
import package.* |
Imports all public classes in package |
package packagename |
Classes in this file belong
to this package |
[ public ] interface interfaceName
block |
Simple Interface definition |
interface interfaceName [ extends
anotherInterface ] block |
Extends interface |
Eccezioni
e Controlli |
|
synchronized ( object ) block |
Waits for lock on object |
try block
catch ( exception ) block
[ finally block ] |
Guarded statements
Executed if exception is thrown
Cleanup code |
try block
[ catch ( exception ) block ]
finally block |
Same as previous example (can use
optional catch or finally) |
Riferimenti
Bibliografici
-
"The Java ™ Language
Specification" disponibile
sul sito FTP di javasoft: ftp://ftp.javasoft.com/docs/specs
-
"Teach yourself
Java in 21 days" L. Lemay C.L. Perkins - SAMS.NET Publishing
(Edito in Italia da Apogeo)
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