jtulach@325: package org.apidesign.sidemeanings.math;
jtulach@325: 
jtulach@325: /** Rewrite of original
jtulach@325:  * <a href="http://source.apidesign.org/hg/apidesign/diff/4e59b6b0e907/samples/composition/src-api1.0/org/apidesign/math/Arithmetica.java">
jtulach@325:  * Arithmetica</a>
jtulach@325:  * class from the composition project
jtulach@325:  * to follow the <q>eliminate fuzzy modifiers</q> rule.
jtulach@325:  *
jtulach@325:  * @author Jaroslav Tulach <jtulach@netbeans.org>
jtulach@325:  * @version 5.0
jtulach@325:  */
jtulach@325: // BEGIN: design.sidemeanings.arith
jtulach@325: public abstract class Arithmetica {
jtulach@325:     // BEGIN: design.sidemeanings.arith.sumTwo
jtulach@325:     public final int sumTwo(int one, int second) {
jtulach@325:         return overridableSumTwo(one, second);
jtulach@325:     }
jtulach@325:     protected abstract int overridableSumTwo(int one, int second);
jtulach@325:     protected final int defaultSumTwo(int one, int second) {
jtulach@325:         return one + second;
jtulach@325:     }
jtulach@325:     // END: design.sidemeanings.arith.sumTwo
jtulach@325:     
jtulach@325:     public final int sumAll(int... numbers) {
jtulach@325:         return overridableSumAll(numbers);
jtulach@325:     }
jtulach@325:     protected abstract int overridableSumAll(int... numbers);
jtulach@325:     protected final int defaultSumAll(int... numbers) {
jtulach@325:         if (numbers.length == 0) {
jtulach@325:             return 0;
jtulach@325:         }
jtulach@325:         int sum = numbers[0];
jtulach@325:         for (int i = 1; i < numbers.length; i++) {
jtulach@376:             // do I want to call sumTwo or defaultSumTwo? 
jtulach@376:             // That is a question!
jtulach@325:             sum = openUpToSubclasses() ?
jtulach@325:                 sumTwo(sum, numbers[i]) :
jtulach@325:                 defaultSumTwo(sum, numbers[i]);
jtulach@325:         }
jtulach@325:         return sum;
jtulach@325:     }
jtulach@325:     
jtulach@325:     public final int sumRange(int from, int to) {
jtulach@325:         return overridableSumRange(from, to);
jtulach@325:     }
jtulach@325:     protected abstract int overridableSumRange(int from, int to);
jtulach@325:     protected final int defaultSumRange(int from, int to) {
jtulach@325:         int len = to - from;
jtulach@325:         if (len < 0) {
jtulach@325:             len = -len;
jtulach@325:             from = to;
jtulach@325:         }
jtulach@325:         int[] array = new int[len + 1];
jtulach@325:         for (int i = 0; i <= len; i++) {
jtulach@325:             array[i] = from + i;
jtulach@325:         }
jtulach@325:         // BEGIN: design.sidemeanings.arith.the.question
jtulach@325:         // Again, an API author has to ask what sumAll one wants to call?
jtulach@325:         // Am I about to open up to subclasses or do I want default impl?
jtulach@325:         return openUpToSubclasses() ?
jtulach@325:             sumAll(array) :
jtulach@325:             defaultSumAll(array);
jtulach@325:         // END: design.sidemeanings.arith.the.question
jtulach@325:     }
jtulach@325: 
jtulach@325:     boolean openUpToSubclasses = true;
jtulach@325:     boolean openUpToSubclasses() {
jtulach@325:         return openUpToSubclasses;
jtulach@325:     }
jtulach@325: 
jtulach@325: 
jtulach@325:     // BEGIN: design.sidemeanings.arith.factory
jtulach@325:     public static Arithmetica create() {
jtulach@325:         return new Arithmetica.Impl();
jtulach@325:     }
jtulach@325:     private static class Impl extends Arithmetica {
jtulach@325:         @Override
jtulach@325:         protected int overridableSumTwo(int one, int second) {
jtulach@325:             return defaultSumTwo(one, second);
jtulach@325:         }
jtulach@325: 
jtulach@325:         @Override
jtulach@325:         protected int overridableSumAll(int... numbers) {
jtulach@325:             return defaultSumAll(numbers);
jtulach@325:         }
jtulach@325: 
jtulach@325:         @Override
jtulach@325:         protected int overridableSumRange(int from, int to) {
jtulach@325:             return defaultSumRange(from, to);
jtulach@325:         }
jtulach@325:     }
jtulach@325:     // END: design.sidemeanings.arith.factory
jtulach@325: 
jtulach@325: }
jtulach@325: // END: design.sidemeanings.arith