package histogram; import java.util.Observable; public class ObservableValues extends Observable implements Values { private Values values; public ObservableValues(Values values) { this.values = values; } @Override public int size() { return values.size(); } @Override public double sum() { return values.sum(); } @Override public double value(int i) { return values.value(i); } @Override public void changeValue(int i, double v) throws NegativeValueException { values.changeValue(i, v); setChanged(); notifyObservers(i); } }