PHP Magic Method Summary 1

PHP Magic Method Summary 1
PHP In addition to a large number of magic variables, there are many _ at the beginning of the Magic method, this article simple summary under:

1 _construct and _destruct did not say, construction and destruction.

2 _call and _callstatic
Example:
Class MyClass () {
Private $a = true;
}

$MYOBJ = new MyClass ();
$MYOBJ->showvalue ();

?>
There's going to be a mistake here, of course, no definition. can be used
Class Greetings {
function __call ($functionName, $argumentsArray) {
echo "Hello,". Ucfirst ($functionName). " !!!";
}
}
$sayHello = new Greetings ();
_call triggers when a call does not define any method

and a _callstatic.
Class Greetings {
static function __callstatic ($functionName, $argumentsArray) {
echo "Hello,". Ucfirst ($functionName). " !!!";
}
}

Greetings::steve ();


3 _set and _get
This is an example of forcing a variable declared in a class to be used:
Class MyClass {
Private $onlyDataMember = 0;
}
$CLASSOBJ = new MyClass ();
$CLASSOBJ->undefineddatamember = ' Some Value ';
Echo $CLASSOBJ->undefineddatamember;
?>
This is the direct output of the undefined value, not good, can be changed to such, mandatory:
Class MyClass {
Private $onlyDataMember = 0;

function __set ($dataMemberName, $dataMemberValue) {
throw new Exception ("Object property $dataMemberName was not writable!");
}

function __get ($dataMemberName) {
throw new Exception ("Object property $dataMemberName was not defined!");
}
}

One more example:
Class userinfo2{

Private $aData = Array ();

}

$oUserInfo 2 = new UserInfo2;

$oUserInfo 2->adata[' UserName '] = ' mu mu zi ';

$oUserInfo 2->adata[' PassWord '] = ' 123456 ';

$oUserInfo 2->adata[' birthdat '] = ' 1978-08-16 ';

echo "Username:". $oUserInfo 2->adata[' UserName '). "
\ n ";

echo "Password:". $oUserInfo 2->adata[' PassWord ']. "
\ n ";

echo "Birthday:" $oUserInfo 2->adata[' Birthday ']. "
\ n ";

Obviously, this code will go wrong, because Adata is a private property of userinfo and cannot be used directly externally, now the problem is that Adata must be paid for, and __set and __get will come in handy at this time:

Class userinfo3{

Private $aData = Array ();

Private $aData = Array ();

function __set ($property, $value) {

$this->adata[$property] = $value;

}

function __get ($property) {

return $this->adata[$property];

}

}

$oUserInfo 3 = new UserInfo3;

$oUserInfo 3->adata[' UserName '] = ' mu mu zi ';

$oUserInfo 3->adata[' PassWord '] = ' 123456 ';

$oUserInfo 3->adata[' birthdat '] = ' 1978-08-16 ';

echo "Username:". $oUserInfo 3->adata[' UserName '). "
\ n ";

echo "Password:". $oUserInfo 3->adata[' PassWord ']. "
\ n ";

echo "Birthday:" $oUserInfo 3->adata[' Birthday ']. "
\ n ";




$CLASSOBJ = new MyClass ();
$CLASSOBJ->undefineddatamember = ' Some Value ';
Echo $CLASSOBJ->undefineddatamember;

?>
This will force an error when the call is made.

4) _invoke
To use objects as functions, typical examples of which we usually use:
Class Mydbusersclass {
Private $recordsArray = Array ();

function __construct ($fetchThisMuchUsers) {
Code for fetching $fetchThisMuchUsers number of records from the database and store them to $recordsArray.
}

function Getusers () {
return $recordsArray;
}
}

$CLASSOBJ = new Mydbusersclass (10);
$users = $CLASSOBJ->getusers ();
foreach ($users as $user) {
echo $user [' UserName ']. '
';
}
?>
You can now use this:
Class Mydbusersclass {
Private $recordsArray = Array ();

function __construct ($fetchThisMuchUsers) {
Code for fetching $fetchThisMuchUsers number of records from the database and store them to $recordsArray.
}

function __invoke ($onlyArgumentItAccepts) {
return $recordsArray;
}
}

$CLASSOBJ = new Mydbusersclass (10);
foreach ($CLASSOBJ () as $user) {
echo $user [' UserName ']. '
';
}
?>

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