Question: AmazonOrderItemList::setOrderId fails, though I'm giving it a string

[mehgcap]

I'm pretty new to working with Amazon, so I hope this isn't a very stupid question. I have an order ID, and I'm trying to get a list of items so I can then get a list of available services. Some of my code is below, slightly modified as the actual code is spread across multiple files and classes:

$amazonOrderNumber = "123-8765432-1234567";
try {
	//first, we need the list of items and quantities
	$logger->debug("Setting up the object to get item details for order {$amazonOrderNumber}.");
	$itemsListObj = new \AmazonOrderItemList();
	if(!$itemsListObj->setOrderId($amazonOrderNumber))
		throw new \Exception("Invalid order number used when getting the list of items. Order number: {$amazonOrderNumber}. Order number variable type: " . gettype($amazonOrderNumber) . ".");
	$logger->debug("Fetching the items/quantities for order $amazonOrderNumber.");

Every time I run this, the exception is thrown. My order number is a string, as the debug log statement shows in my log, but setOrderId won't accept it for some reason. The function seems only to care that the order ID be a string or a number, so I can't imagine why I am getting stuck at this stage. What is the very obvious, simple thing I'm doing wrong? :) Thanks in advance for any ideas!

[mehgcap]

As is so often the case, I figured out the problem soon after posting my question. However, I would now like to make a suggestion.

The problem was that I used the "if(!$obj->function())" syntax. As the functions I was testing return false on failure, but nothing on success, PHP was interpreting the null response from the functions as false. If I instead use "if($obj->function() === false)", things work perfectly.

This leads me to my suggestion. If a function can return a boolean, and returns false on failure, it should return true on success. I'm not a PHP expert, so there may well be a good reason this library is set up this way. Please ignore me if this is the case. It just seems like it would make more sense to return a boolean value no matter what, rather than not returning anything on success. Thanks.

[Peardian]

You're right, returning true in the setter functions would make the design much better. Thank you for the suggestion.