hg/apidesign: samples/composition/src-api2.0-runtime/org/apidesign/math/Arithmetica.java@40cabcdcd2be

     1 package org.apidesign.math;

     3 import org.apidesign.runtime.check.RuntimeCheck;

     5 /** Class to simplify arithmetical operations, improved version to compute

     6  * the sum for ranges, but only if the virtual machine is configured to

     7  * run in incompatible mode.

     8  *

     9  * @author Jaroslav Tulach <jtulach@netbeans.org>

    10  * @version 2.0

    11  */

    12 // BEGIN: design.composition.arith.runtime

    13 public class Arithmetica {

    14     public int sumTwo(int one, int second) {

    15         return one + second;

    16     }

    18     public int sumAll(int... numbers) {

    19         if (numbers.length == 0) {

    20             return 0;

    21         }

    22         int sum = numbers[0];

    23         for (int i = 1; i < numbers.length; i++) {

    24             sum = sumTwo(sum, numbers[i]);

    25         }

    26         return sum;

    27     }

    29     public int sumRange(int from, int to) {

    30         if (calledByV2AwareLoader()) {

    31             return sumRange2(from, to);

    32         } else {

    33             return sumRange1(from, to);

    34         }

    35     }

    37     private int sumRange1(int from, int to) {

    38         int len = to - from;

    39         if (len < 0) {

    40             len = -len;

    41             from = to;

    42         }

    43         int[] array = new int[len + 1];

    44         for (int i = 0; i <= len; i++) {

    45             array[i] = from + i;

    46         }

    47         return sumAll(array);

    48     }

    50     private int sumRange2(int from, int to) {

    51         return (from + to) * (Math.abs(to - from) + 1) / 2;

    52     }

    54     private static boolean calledByV2AwareLoader() {

    55         // BEGIN: design.composition.arith2.6.runtime

    56         StackTraceElement[] arr = Thread.currentThread().getStackTrace();

    57         ClassLoader myLoader = Arithmetica.class.getClassLoader();

    58         for (int i = 0; i < arr.length; i++) {

    59             ClassLoader caller = arr[i].getClass().getClassLoader();

    60             if (myLoader == caller) {

    61                 continue;

    62             }

    63             if (RuntimeCheck.requiresAtLeast(

    64                 "2.0", "org.apidesign.math", caller

    65             )) {

    66                 return true;

    67             }

    68             return false;

    69         }

    70         return true;

    71         // END: design.composition.arith2.6.runtime

    72     }

    74 }

    75 // END: design.composition.arith.runtime

author	Jaroslav Tulach <jaroslav.tulach@apidesign.org>
	Thu, 30 Oct 2014 21:30:10 +0100
changeset 409	40cabcdcd2be
parent 321	06bf3a32eaa0
permissions	-rw-r--r--