sample.php

class NullObject
{
    public function __call($name, $arguments)
    {
        return $this;
    }
}

class Klass
{
    public function process1()
    {
        try {
            // do something
            // throw exception if error occurs
            return $this;
        } catch (Exception $e) {
            return new NullObject;
        }
    }

    public function process2()
    {
        // do something
    }
}