Use a wildcard.
class Stats<T extends Number> { T[] nums; Stats(T[] o) { nums = o; } double average() { double sum = 0.0; for (int i = 0; i < nums.length; i++) sum += nums[i].doubleValue(); return sum / nums.length; } boolean sameAvg(Stats<?> ob) { if (average() == ob.average()) return true; return false; } } class WildcardDemo { public static void main(String args[]) { Integer inums[] = { 1, 2, 3, 4, 5 }; Stats<Integer> iob = new Stats<Integer>(inums); double v = iob.average(); System.out.println("iob average is " + v); Double dnums[] = { 1.1, 2.2, 3.3, 4.4, 5.5 }; Stats<Double> dob = new Stats<Double>(dnums); double w = dob.average(); System.out.println("dob average is " + w); Float fnums[] = { 1.0F, 2.0F, 3.0F, 4.0F, 5.0F }; Stats<Float> fob = new Stats<Float>(fnums); double x = fob.average(); System.out.println("fob average is " + x); // See which arrays have same average. System.out.print("Averages of iob and dob "); if (iob.sameAvg(dob)) System.out.println("are the same."); else System.out.println("differ."); System.out.print("Averages of iob and fob "); if (iob.sameAvg(fob)) System.out.println("are the same."); else System.out.println("differ."); } }
1. | Java generic: Use a wildcard. | ||
2. | Java generic: Bounded Wildcard arguments | ||
3. | Bounded Wildcard arguments. | ||
4. | Generic cast | ||
5. | Generic structure with constraints | ||
6. | Return an implementation of a Comparable |