where getOrderStrategy wraps the order in a DisputeAcceptedStrategy, DisputeCancelledStrategy, DisputeOlderThan7DaysStrategy, etc. each of which know how to handle the given situation

where getOrderStrategy wraps the order in a DisputeAcceptedStrategy, DisputeCancelledStrategy, DisputeOlderThan7DaysStrategy, etc. each of which know how to handle the given situation.

Edit, to answer question in comments.

could you please elaborate more on your code. What I understood is that getOrderStrategy is a factory method that returns a strategy object depending on the order status, but what are the preProcess() and preProcess() functions. Also why did you pass $this to updateOrderHistory($this)?

You're focussing on the example, which could be completely inappropriate for your case. I don't have enough detail to be sure of the best implementation, so I came up with a vague example.

The one common piece of code you have is insertRecordInOrderHistoryTable, so I chose to use that (with a slightly more generic name) as the central point of the strategy. I pass $this to it, because it is calling a method on this, with $order and a different string per strategy.

So, basically, I envision each of those looking like this:

public function updateOrderHistory($auth) {
    $auth.insertRecordInOrderHistoryTable($order, 'cancelled');
}

Where $order is a private member of the Strategy (remember I said it should wrap the order) and the second argument is different in each class. Again, this might be entirely inappropriate. You might want to move insertRecordInOrderHistoryTable to a base Strategy class and not pass the Authorization class in. Or you might want to do something entirely different, it was just an example.

Likewise, I limited the rest of the differing code to pre- and postProcess methods. This is almost certainly not the best you can do with it. Give it more appropriate names. Split it down into multiple methods. Whatever makes the calling code more readable.

You might prefer to do this:

var $strategy = $this.getOrderStrategy($order);
$strategy->setStatus();
$strategy->closeDisputeIfNecessary();
$strategy->refundIfNecessary();
$strategy->insertRecordInOrderHistoryTable($this);                        
$strategy->rollBackRefundIfNecessary();

And have some of your Strategies implement empty methods for the "IfNecessary" methods.

Whatever makes the calling code more readable.