Dependency Injection and passing arguments - php

Question

I have a question about Dependency Injection in PHP.
I currently have this 3 classes:
Staff.php
<?php
class Staff
{
public function name($id)
{
return 'returning staff with id ' . $id;
}
}
Projects.php
<?php
class Projects
{
..... projects related functions
}
ProjectsManager.php
<?php
class ProjectsManager
{
private $staff = null;
private $projects = null;
public function __construct(Staff $staff, Projects $projects)
{
$this->staff = $staff;
$this->projects = $projects;
}
public function staff()
{
return $this->staff;
}
public function projects()
{
return $this->projects;
}
}
Those classes are instantiated like this:
$staff = new Staff;
$projects = new Projects;
$app = new ProjectsManager($staff, $projects);
echo $app->staff()->name(5);
The above is working, but what I would like to do is something like this:
$employee = $app->staff(5);
echo $employee->name();
echo $employee->position();
echo $employee->email();
How can I handle the dependency to achieve this?

Answer 1

You can simply add the set function in Staff class and call it in ProjectsManager:
<?php
class Staff
{
private $id = null;
public function name()
{
return 'returning staff with id ' . $this->id;
}
public function setId($id)
{
$this->id = $id;
}
}
class Projects
{
//..... projects related functions
}
class ProjectsManager
{
private $staff = null;
private $projects = null;
public function __construct(Staff $staff, Projects $projects)
{
$this->staff = $staff;
$this->projects = $projects;
}
public function staff($id = null)
{
$this->staff->setId($id);
return $this->staff;
}
public function projects($val = null)
{
return $this->projects;
}
}
$staff = new Staff;
$projects = new Projects;
$app = new ProjectsManager($staff, $projects);
$employee = $app->staff(5);
echo $employee->name();

Answer 2

$employee = $app->staff()->name(5);
//$app is the ProjectsManager
//$app->staff() returns it's Staff object
//staff()->name(5) Invokes the Staff object's name function
//Returns 'Returning staff with id 5'
echo $employee->name();
echo $employee->position();
echo $employee->email();
To avoid confusion, I would also suggest prefix some of those functions with get (eg. $app->getStaff()->getFromId(#))
Also, be sure to modify staff()->name(#) to actually return an object and not a string.