DivModPresenterObs.java - Model klassen med tilkobling og notification af observer.

Lecture 12 - slide 25 : 30 Program 1

class DivModCalculator extends Observable{ private DivModPresenterObs viewObject; IntPair inputMemory, outputMemory; public DivModCalculator(DivModPresenterObs viewObject) { this.viewObject = viewObject; addObserver(viewObject); inputMemory = null; outputMemory = null; } private IntPair divMod(int x, int y){ // require x > 0 && y > 0 ; int rest = x; int quotient = 0; while (rest >= y) { // invariant rest + quotient * y = x ; rest = rest - y; quotient = quotient + 1; } return (new IntPair(quotient,rest)); // ensure rest + quotient * y = x && rest < y && rest >= 0 ; } // end div public void doCalculate(int input1, int input2){ inputMemory = new IntPair(input1, input2); if (input1 > 0 && input2 > 0) outputMemory = divMod(input1, input2); else outputMemory = new IntPair(-1, -1); setChanged(); // now I am changed notifyObservers(); // ... and therefore I notifiy my observers } public IntPair getResult(){ return outputMemory; } } // end DivModCalculator