Annotations to detect method calls with wrong order of String parameters

Question

We have a big application which uses a lot of Strings:

• for serial numbers
• for product names
• for order number
• for customer references
• ... and many more ...

Unfortunately our developers are only human. Sometimes the String values get mixed up when calling methods. For example:

// this method
public void addProductToOrder(String order, String productname, String serialnumber);

// should be called like:
addProductToOrder(order, productname, serialnumber);

// but is sometimes mistakenly called as:
addProductToOrder(productname, serialnumber, order);

Switching 2 parameters is hard to detect when your method takes about 30 of these parameters. (Yes, it's one of those heavy business applications)

Sidenote: We wouldn't have this problem if we created our own class SerialNumber which just acts as a wrapper around String. But that seems so wrong.

Recently, I started to wonder if there is a way to detect mix-ups using custom annotations. After all, there are already annotations like Nullable, NonNull ... And this is not very different.

We would like to annotate our source code, for example like this:

public void addProductToOrder(@OrderReference String order, @ProductName String productname, @SerialNumber String serialnumber);

Next, we would like to find a way to make our IDE detect that 2 parameters were switched here.

@OrderReference String order = "ORDER_001";
@SerialNumber String sn = "0001-1213-007";
@ProductName String productname = "beer";
addProductToOrder(productname, serialnumber, order);
// should have been: addProductToOrder(order, productname, serialnumber);

We are using IntelliJ IDE. What is possible without writing IDE plugins ?

Answer 1

While you should go with ControlAltDel's comment as an ultimate solution, Intelij does have an inspection "Suspicious variable/parameter name combination" that might help. You can enter common parameter names and it will warn you if it thinks the local variables do not match.