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jtulach@321
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package org.apidesign.math;
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jtulach@155
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jtulach@155
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import org.apidesign.runtime.check.RuntimeCheck;
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jtulach@155
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jtulach@155
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/** Class to simplify arithmetical operations, improved version to compute
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jtulach@155
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* the sum for ranges, but only if the virtual machine is configured to
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jtulach@155
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* run in incompatible mode.
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jtulach@155
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*
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jtulach@155
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* @author Jaroslav Tulach <jtulach@netbeans.org>
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jtulach@155
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* @version 2.0
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jtulach@155
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*/
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jtulach@323
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// BEGIN: design.composition.arith.runtime
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jtulach@155
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public class Arithmetica {
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jtulach@155
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public int sumTwo(int one, int second) {
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jtulach@155
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return one + second;
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jtulach@155
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}
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jtulach@155
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jtulach@155
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public int sumAll(int... numbers) {
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jtulach@187
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if (numbers.length == 0) {
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jtulach@187
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return 0;
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jtulach@187
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}
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jtulach@155
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int sum = numbers[0];
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jtulach@155
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for (int i = 1; i < numbers.length; i++) {
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jtulach@155
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sum = sumTwo(sum, numbers[i]);
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jtulach@155
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}
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jtulach@155
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return sum;
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jtulach@155
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}
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jtulach@155
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jtulach@155
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public int sumRange(int from, int to) {
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jtulach@155
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if (calledByV2AwareLoader()) {
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jtulach@155
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return sumRange2(from, to);
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jtulach@155
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} else {
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jtulach@155
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return sumRange1(from, to);
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jtulach@155
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}
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jtulach@155
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}
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jtulach@155
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jtulach@155
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private int sumRange1(int from, int to) {
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jtulach@155
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int len = to - from;
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jtulach@210
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if (len < 0) {
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jtulach@210
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len = -len;
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jtulach@210
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from = to;
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jtulach@210
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}
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jtulach@155
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int[] array = new int[len + 1];
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jtulach@155
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for (int i = 0; i <= len; i++) {
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jtulach@155
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array[i] = from + i;
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jtulach@155
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}
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jtulach@155
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return sumAll(array);
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jtulach@155
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}
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jtulach@155
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jtulach@155
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private int sumRange2(int from, int to) {
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jtulach@210
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return (from + to) * (Math.abs(to - from) + 1) / 2;
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jtulach@155
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}
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jtulach@155
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jtulach@155
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private static boolean calledByV2AwareLoader() {
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jtulach@155
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// BEGIN: design.composition.arith2.6.runtime
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jtulach@155
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StackTraceElement[] arr = Thread.currentThread().getStackTrace();
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jtulach@155
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ClassLoader myLoader = Arithmetica.class.getClassLoader();
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jtulach@155
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for (int i = 0; i < arr.length; i++) {
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jtulach@155
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ClassLoader caller = arr[i].getClass().getClassLoader();
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jtulach@155
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if (myLoader == caller) {
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jtulach@155
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continue;
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jtulach@155
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}
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jtulach@323
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if (RuntimeCheck.requiresAtLeast(
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jtulach@323
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"2.0", "org.apidesign.math", caller
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jtulach@323
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)) {
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jtulach@155
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return true;
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jtulach@155
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}
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jtulach@155
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return false;
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jtulach@155
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}
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jtulach@155
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return true;
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jtulach@155
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// END: design.composition.arith2.6.runtime
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jtulach@155
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}
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jtulach@155
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jtulach@155
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}
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jtulach@323
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// END: design.composition.arith.runtime
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