jtulach@155: package api;
jtulach@155: 
jtulach@155: import org.apidesign.runtime.check.RuntimeCheck;
jtulach@155: 
jtulach@155: /** Class to simplify arithmetical operations, improved version to compute
jtulach@155:  * the sum for ranges, but only if the virtual machine is configured to
jtulach@155:  * run in incompatible mode.
jtulach@155:  *
jtulach@155:  * @author Jaroslav Tulach <jtulach@netbeans.org>
jtulach@155:  * @version 2.0
jtulach@155:  */
jtulach@155: public class Arithmetica {
jtulach@155:     public int sumTwo(int one, int second) {
jtulach@155:         return one + second;
jtulach@155:     }
jtulach@155:     
jtulach@155:     public int sumAll(int... numbers) {
jtulach@187:         if (numbers.length == 0) {
jtulach@187:             return 0;
jtulach@187:         }
jtulach@155:         int sum = numbers[0];
jtulach@155:         for (int i = 1; i < numbers.length; i++) {
jtulach@155:             sum = sumTwo(sum, numbers[i]);
jtulach@155:         }
jtulach@155:         return sum;
jtulach@155:     }
jtulach@155:     
jtulach@155:     public int sumRange(int from, int to) {
jtulach@155:         if (calledByV2AwareLoader()) {
jtulach@155:             return sumRange2(from, to);
jtulach@155:         } else {
jtulach@155:             return sumRange1(from, to);
jtulach@155:         }
jtulach@155:     }
jtulach@155: 
jtulach@155:     private int sumRange1(int from, int to) {
jtulach@155:         int len = to - from;
jtulach@210:         if (len < 0) {
jtulach@210:             len = -len;
jtulach@210:             from = to;
jtulach@210:         }
jtulach@155:         int[] array = new int[len + 1];
jtulach@155:         for (int i = 0; i <= len; i++) {
jtulach@155:             array[i] = from + i;
jtulach@155:         }
jtulach@155:         return sumAll(array);
jtulach@155:     }
jtulach@155:     
jtulach@155:     private int sumRange2(int from, int to) {
jtulach@210:         return (from + to) * (Math.abs(to - from) + 1) / 2;
jtulach@155:     }
jtulach@155: 
jtulach@155:     private static boolean calledByV2AwareLoader() {
jtulach@155:         // BEGIN: design.composition.arith2.6.runtime
jtulach@155:         StackTraceElement[] arr = Thread.currentThread().getStackTrace();
jtulach@155:         ClassLoader myLoader = Arithmetica.class.getClassLoader();
jtulach@155:         for (int i = 0; i < arr.length; i++) {
jtulach@155:             ClassLoader caller = arr[i].getClass().getClassLoader();
jtulach@155:             if (myLoader == caller) {
jtulach@155:                 continue;
jtulach@155:             }
jtulach@155:             if (RuntimeCheck.requiresAtLeast("2.6", "api.Arithmetica", caller)) {
jtulach@155:                 return true;
jtulach@155:             }
jtulach@155:             return false;
jtulach@155:         }
jtulach@155:         return true;
jtulach@155:         // END: design.composition.arith2.6.runtime
jtulach@155:     }
jtulach@155:     
jtulach@155: }