PHP 7.2.7 Released

Componere\Abstract\Definition::addTrait

(Componere 2 >= 2.1.0)

Componere\Abstract\Definition::addTraitAdd Trait

Description

public Definition Componere\Abstract\Definition::addTrait ( string $trait )

Shall use the given trait for the current definition

Parameters

trait

The case insensitive name of a trait

Return Values

The current Definition

Exceptions

Warning

Shall throw RuntimeException if Definition was registered

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User Contributed Notes 1 note

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ASchmidt at Anamera dot net
3 months ago
Adding a trait is an efficient way to extend a "final" class, overriding methods and adding new ones, without having to individually add each method as a closure. It also results in more readable code.

<?php
declare(strict_types=1);

/*
*  Final class would normally prevent extending.
*/
final class ParentC
{
    public
$parentvar;
    public
$secondvar;
   
    function
__construct() { echo( "\r\n<br/>".$this->parentvar = 'set by '.get_class().'->parentconstruct' ); }
    function
parentf() { echo( "\r\n<br/>".get_class().'->parentf >> '.$this->parentvar ); }
}

/*
*  Extended class members.
*/
trait ChildC /* extends ParentC */
{
    function
__construct() {
       
// Call parent constructor.
       
parent::__construct();
       
// Access an inherited property set by parent constructor.
       
echo( "\r\n<br/>".get_class().'->overridden_constructor >> '.$this->parentvar );
    }
   
    function
parentf() {
       
// Call overridden parent method.
       
parent::parentf();
       
// Access an inherited property set by constructor.
       
echo( "\r\n<br/>".get_class().'->overridden_parentf >> '.$this->parentvar );
    }
   
    function
dynamicf( $parm = null ) {
       
// Populate a parent class property.
       
$this->secondvar = empty( $parm ) ? 'set by '.get_class().'->dynamicf' : $parm;
       
// Access an inherited property set by parent constructor.
       
echo( "\r\n<br/>".get_class().'->dynamicf >> '.$this->parentvar );
    }
}

/*
*  Register the dynamic child class "ChildC", which is
*  derived by extending "ParentC" with members supplied as "ChildC" trait.
*/
$definition = new \Componere\Definition( 'ChildC', ParentC::class );
$definition->addTrait( 'ChildC' );
$definition ->register();

/*
*  Instantiate the dynamic child class,
*  and access its own and inherited members.
*/
$dyno = new ChildC;
$dyno->parentf();
$dyno->dynamicf( 'myvalue ');

// Our object is also recognized as instance of parent!
var_dump( $dyno instanceof ChildC, $dyno instanceof ParentC, is_a( $dyno, 'ParentC') );
var_dump( $dyno );
?>

will output:

set by ParentC->parentconstruct
ChildC->overridden_constructor >> set by ParentC->parentconstruct
ParentC->parentf >> set by ParentC->parentconstruct
ChildC->overridden_parentf >> set by ParentC->parentconstruct
ChildC->dynamicf >> set by ParentC->parentconstruct

boolean true
boolean true
boolean true

object(ChildC)[2]
  public 'parentvar' => string 'set by ParentC->parentconstruct' (length=31)
  public 'secondvar' => string 'myvalue ' (length=8)
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