PHP Magic 1

PHP magic methods summary 1PHP in addition to a large number of magic variables, there are also a lot of magic methods at the beginning of the _, a simple summary of this article: construct and _ destruct will not talk about, structure and analysis structure. 2_call and _ callStatic & nbsp; example: & nbsp; & lt ;? Php & nb PHP magic methods summary 1
In addition to a large number of magic variables, PHP also has a lot of magic methods starting with _. This article briefly summarizes:

1 _ construct and _ destruct won't be mentioned, structure and analysis structure.

2 _ call and _ callStatic
Example:
Class myClass (){
Private $ a = true;
}

$ MyObj = new myClass ();
$ MyObj-> showValue ();

?>
Errors will be mentioned here. of course they are not defined. they can be used.
Class Greetings {
Function _ call ($ functionName, $ argumentsArray ){
Echo "Hello,". ucfirst ($ functionName )."!!! ";
}
}
$ SayHello = new Greetings ();
_ CALL is triggered when no method is defined in the CALL.

And _ callStatic
Class Greetings {
Static function _ callStatic ($ functionName, $ argumentsArray ){
Echo "Hello,". ucfirst ($ functionName )."!!! ";
}
}

Greetings: steve ();


3 _ set and _ get
This is to force variables declared in the class to be used. for example:
Class myClass {
Private $ onlyDataMember = 0;
}
$ ClassObj = new myClass ();
$ ClassObj-> undefinedDataMember = 'some value ';
Echo $ classObj-> undefinedDataMember;
?>
This is an undefined value directly output, which is not very good. you can change it to this, which is mandatory:
Class myClass {
Private $ onlyDataMember = 0;

Function _ set ($ dataMemberName, $ dataMemberValue ){
Throw new Exception ("Object property $ dataMemberName is not writable! ");
}

Function _ get ($ dataMemberName ){
Throw new Exception ("Object property $ dataMemberName is not defined! ");
}
}

Another example:
Class UserInfo2 {

Private $ aData = array ();

}

$ OUserInfo2 = new UserInfo2;

$ OUserInfo2-> aData ['username'] = 'Mu Muzi ';

$ OUserInfo2-> aData ['password'] = '000000 ';

$ OUserInfo2-> aData ['birthdat '] = '2017-08-16 ';

Echo "UserName:". $ oUserInfo2-> aData ['username']."
\ N ";

Echo "PassWord:". $ oUserInfo2-> aData ['password']."
\ N ";

Echo "Birthdate:". $ oUserInfo2-> aData ['birthday']."
\ N ";

Obviously, this code will cause an error. because aData is a private property of UserInfo and cannot be used externally, the problem is that aData must be paid, in this case, _ set and _ get come in handy:

Class UserInfo3 {

// Private $ aData = array ();

Private $ aData = array ();

Function _ set ($ property, $ value ){

$ This-> aData [$ property] = $ value;

}

Function _ get ($ property ){

Return $ this-> aData [$ property];

}

}

$ OUserInfo3 = new UserInfo3;

$ OUserInfo3-> aData ['username'] = 'Mu Muzi ';

$ OUserInfo3-> aData ['password'] = '000000 ';

$ OUserInfo3-> aData ['birthdat '] = '2017-08-16 ';

Echo "UserName:". $ oUserInfo3-> aData ['username']."
\ N ";

Echo "PassWord:". $ oUserInfo3-> aData ['password']."
\ N ";

Echo "Birthdate:". $ oUserInfo3-> aData ['birthday']."
\ N ";




$ ClassObj = new myClass ();
$ ClassObj-> undefinedDataMember = 'some value ';
Echo $ classObj-> undefinedDataMember;

?>
In this way, an error is forcibly reported during the call.

4) _ invoke
An object is used as a function. a typical example is:
Class myDbUsersClass {
Private $ recordsArray = array ();

Function _ construct ($ fetchThisMuchUsers ){
// Code for fetching $ fetchThisMuchUsers number of records from 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 use the following code:
Class myDbUsersClass {
Private $ recordsArray = array ();

Function _ construct ($ fetchThisMuchUsers ){
// Code for fetching $ fetchThisMuchUsers number of records from database and store them to $ recordsArray.
}

Function _ invoke ($ onlyArgumentItAccepts ){
Return $ recordsArray;
}
}

$ ClassObj = new myDbUsersClass (10 );
Foreach ($ classObj () as $ user ){
Echo $ user ['username'].'
';
}
?>