To better understand the Extract Interface operation, let’s look at an example. Suppose you review your code and notice that a number of your domain objects share similar properties and methods. Let’s say the objects
Product all contain properties for
Name and methods for
Delete. In this case, you should consider extracting this commonality into a standard interface that each of your domain objects would implement. Let’s look at how the Extract Interface refactoring operation aids in this regard.
First, you position your cursor on the target class whose members you want to extract. In the example, choose the
Invoice class and position the cursor on the class name. Then press Ctrl+. to ...