jtulach@148: package api;
jtulach@148: 
jtulach@148: /** Class to simplify arithmetical operations, improved version to compute
jtulach@148:  * the sum for ranges, but only if the virtual machine is configured to
jtulach@148:  * run in incompatible mode.
jtulach@148:  *
jtulach@148:  * @author Jaroslav Tulach <jtulach@netbeans.org>
jtulach@148:  * @version 2.0
jtulach@148:  */
jtulach@148: // BEGIN: design.composition.arith2.0.property
jtulach@148: public class Arithmetica {
jtulach@148:     public int sumTwo(int one, int second) {
jtulach@148:         return one + second;
jtulach@148:     }
jtulach@148:     
jtulach@148:     public int sumAll(int... numbers) {
jtulach@187:         if (numbers.length == 0) {
jtulach@187:             return 0;
jtulach@187:         }
jtulach@148:         int sum = numbers[0];
jtulach@148:         for (int i = 1; i < numbers.length; i++) {
jtulach@148:             sum = sumTwo(sum, numbers[i]);
jtulach@148:         }
jtulach@148:         return sum;
jtulach@148:     }
jtulach@148:     
jtulach@148:     public int sumRange(int from, int to) {
jtulach@149:         // BEGIN: design.composition.arith2.0.property.if
jtulach@148:         if (Boolean.getBoolean("arithmetica.v2")) {
jtulach@148:             return sumRange2(from, to);
jtulach@148:         } else {
jtulach@148:             return sumRange1(from, to);
jtulach@148:         }
jtulach@149:         // END: design.composition.arith2.0.property.if
jtulach@148:     }
jtulach@148: 
jtulach@148:     private int sumRange1(int from, int to) {
jtulach@148:         int len = to - from;
jtulach@210:         if (len < 0) {
jtulach@210:             len = -len;
jtulach@210:             from = to;
jtulach@210:         }
jtulach@148:         int[] array = new int[len + 1];
jtulach@148:         for (int i = 0; i <= len; i++) {
jtulach@148:             array[i] = from + i;
jtulach@148:         }
jtulach@148:         return sumAll(array);
jtulach@148:     }
jtulach@148:     
jtulach@148:     private int sumRange2(int from, int to) {
jtulach@210:         return (from + to) * (Math.abs(to - from) + 1) / 2;
jtulach@148:     }
jtulach@152: }
jtulach@148: // END: design.composition.arith2.0.property