Question

In the code snippet below when I originally designed it, the “next number” needed to send the next incremented value throughout the execution of the application. So I made the class a singleton. However, with some recent change in requirements I needed to do a reset on the “next number”. I just added a reset method to do that. However, it definitely violates the Singleton pattern and also I know it is not a good idea to initialize a static member this way.

What do you think I should do instead?

public final class GetNextNumber {
    private static GetNextNumber instance; 
    private static Integer nextNumber=1;
    private GetNextNumber() {
    }
    public static synchronized GetNextNumber getInstance() {
        if(instance==null){
            instance = new GetNextNumber();
        }
        return instance;
    } 
    protected Integer getNextNumber(){
        return nextNumber++;
    }
    protected synchronized void reset(){
        nextNumber=1;
    }
    public Object clone() throws CloneNotSupportedException {
        throw new CloneNotSupportedException();
    }
}

Answer 1

why aren’t the fields just instance variables? theres no need for static here.

reset doesn’t need to be synchronized either, unless getNextNumber is as well.