PHP method chaining or fluent interface?

I am using PHP 5 and I’ve heard of a new featured in the object-oriented approach, called ‘method chaining’. What is it exactly? How do I implement it?

Answer

It’s rather simple, really. You have a series of mutator methods that all return the original (or other) object. That way, you can keep calling methods on the returned object.

<?php
class fakeString
{
    private $str;
    function __construct()
    {
        $this->str = "";
    }
    
    function addA()
    {
        $this->str .= "a";
        return $this;
    }
    
    function addB()
    {
        $this->str .= "b";
        return $this;
    }
    
    function getStr()
    {
        return $this->str;
    }
}


$a = new fakeString();


echo $a->addA()->addB()->getStr();

This outputs “ab”

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