hg/apidesign: samples/composition/src-api2.0-runtime/api/Arithmetica.java@acf2c31e22d4

     1 package api;

     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 public class Arithmetica {

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

    14         return one + second;

    15     }

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

    18         if (numbers.length == 0) {

    19             return 0;

    20         }

    21         int sum = numbers[0];

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

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

    24         }

    25         return sum;

    26     }

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

    29         if (calledByV2AwareLoader()) {

    30             return sumRange2(from, to);

    31         } else {

    32             return sumRange1(from, to);

    33         }

    34     }

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

    37         int len = to - from;

    38         if (len < 0) {

    39             len = -len;

    40             from = to;

    41         }

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

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

    44             array[i] = from + i;

    45         }

    46         return sumAll(array);

    47     }

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

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

    51     }

    53     private static boolean calledByV2AwareLoader() {

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

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

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

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

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

    59             if (myLoader == caller) {

    60                 continue;

    61             }

    62             if (RuntimeCheck.requiresAtLeast("2.6", "api.Arithmetica", caller)) {

    63                 return true;

    64             }

    65             return false;

    66         }

    67         return true;

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

    69     }

    71 }

author	Jaroslav Tulach <jtulach@netbeans.org>
	Sat, 14 Jun 2008 10:04:53 +0200
changeset 210	acf2c31e22d4
parent 209	1c999569643b
permissions	-rw-r--r--