Using getters within class methods

Question

If you have a class with some plain get/set properties, is there any reason to use the getters within the class methods, or should you just use the private member variables? I think there could be more of an argument over setters (validation logic?), but I'm wondering just about getters.

For example (in Java) - is there any reason to use option 2?:

public class Something
{
    private int messageId;
    public int getMessageId() { return this.messageId; }
    public void setMessage(int messageId) { this.messageId = messageId; }

    public void doSomething()
    {
        // Option 1:
        doSomethingWithMessageId(messageId);

        // Option 2:
        doSomethingWithMessageId(getMessageId());
    }
}

Answer 1

Java programmers in general tend to be very consistent about using getter methods. I program multiple languages and I'm not that consistent about it ;)

I'd say as long as you don't make a getter it's ok to use the raw variable - for private variables. When you make a getter, you should be using only that. When I make a getter for a private field, my IDE suggests that it replace raw field accesses for me automatically when I introduce a getter. Switching to using a getter is only a few keystrokes away (and without any chance of introducing errors), so I tend to delay it until I need it.

Of course, if you want to stuff like getter-injection, some types of proxying and subclassing framworks like hibernate, you have to user getters!

Answer 2

With getters you wont accidentally modify the variables :) Also, if you use both getters and the "raw" variable, your code can get confused.

Also, if you use inheritance and redefined the getter methods in child classes, getter-using methods will work properly, whereas those using the raw variables would not.