package genericity;

public class ArrayOps {

	/**
	 * @requires A.length >= 1
	 * @param A a non-empty array of some type
	 * @return the middle element of the array
	 */
	static <T> T midpoint (T[] A) {
		assert A.length >= 1;
		return A[A.length/2];
	}

	<T> int nonNullLength (T[] A) {
		int count = 0;
		for (T t : A) {
			if (t != null) {
				count++;
			}
		}
		return count;
	}
	
	public static void main(String[] args) {
		String result;
		int count;
		ArrayOps arrayWorker = new ArrayOps();
		
		//correct usage:
		result = ArrayOps.midpoint(args);
		result = ArrayOps.<String>midpoint(args);
		count = arrayWorker.nonNullLength(args);
		count = arrayWorker.<String>nonNullLength(args);
		
		//correct syntax, poor style
		result = arrayWorker.midpoint(args); //static member via reference
		result = arrayWorker.<String>midpoint(args); //static member via reference

		//compile-time errors
//		result = <String>midpoint(args); //syntax error
//		result = ArrayOps.<Integer>midpoint(args); //type mismatch
//		count = <String>nonNullLength(args); //syntax error
//		count - arrayWorker.<Integer>nonNullLength(args); //type mismatch
		
		System.out.println(result + count);
	}
}