构建一个单身人士班

Question

An ethical question here.

I'm planning on using several manager classes in my new project that will be performing various tasks across the whole project. These classes are singletons, but require construction based on parameters.

As to when/where this construction has to happen, I have mixed feelings. I have these options so far:

Option A

It's easy to just pass these parameters to the getInstance method while having a default null value. On the very first call the parameters will be used, and any additional calls completely ignore them.

While this works, doing so feels rather unlogical, for the following reasons:

• It makes documentation unclear. getInstance' first parameter must be of type Collection, but can be null... what's going on here? You can argue that writing a line about this in the description will clear it up, but I'd prefer clarification to be unneccesary.

• It feels faulty to pass getInstance any construction parameters. This is due to the fact that the method name does not explicity hint towards construction, making it unclear it will happen.

Option B

I'm thinking about a setup method. This method takes all parameters, calls the class constructor, and changes the internal class state to initialized.

When calling the getInstance method prior to setup, it will throw a NotInitializedException. After setup has been called, any additional calls to setup will result in a PreviouslyInitializedException.

After setup has been called, getInstance becomes available.

Personally, this option appeals more to me. But it feels excessive.

What option do you prefer? And why?

Answer 1

I would probably try and ditch the singleton approach and pass manager classes around to whatever needs them.

$manager = new Manager( $collection, $var, $var2 );

$other_class = New OtherClass( $manager );
//or
$other_class = New OtherClass;
$other_class->manager = $manager;
//or
$other_class = New OtherClass;
$other_class->setManager( $manager );