package org.apidesign.sidemeanings.math;

 /** Rewrite of original

  * <a href="http://source.apidesign.org/hg/apidesign/diff/4e59b6b0e907/samples/composition/src-api1.0/org/apidesign/math/Arithmetica.java">

  * Arithmetica</a>

  * class from the composition project

  * to follow the <q>eliminate fuzzy modifiers</q> rule.

  *

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

  * @version 5.0

  */

 // BEGIN: design.sidemeanings.arith

 public abstract class Arithmetica {

     // BEGIN: design.sidemeanings.arith.sumTwo

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

         return overridableSumTwo(one, second);

     }

     protected abstract int overridableSumTwo(int one, int second);

     protected final int defaultSumTwo(int one, int second) {

         return one + second;

     }

     // END: design.sidemeanings.arith.sumTwo

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

         return overridableSumAll(numbers);

     }

     protected abstract int overridableSumAll(int... numbers);

     protected final int defaultSumAll(int... numbers) {

         if (numbers.length == 0) {

             return 0;

         }

         int sum = numbers[0];

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

             // do I want to call sumTwo or defaultSumTwo? 

             // That is a question!

             sum = openUpToSubclasses() ?

                 sumTwo(sum, numbers[i]) :

                 defaultSumTwo(sum, numbers[i]);

         }

         return sum;

     }

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

         return overridableSumRange(from, to);

     }

     protected abstract int overridableSumRange(int from, int to);

     protected final int defaultSumRange(int from, int to) {

         int len = to - from;

         if (len < 0) {

             len = -len;

             from = to;

         }

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

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

             array[i] = from + i;

         }

         // BEGIN: design.sidemeanings.arith.the.question

         // Again, an API author has to ask what sumAll one wants to call?

         // Am I about to open up to subclasses or do I want default impl?

         return openUpToSubclasses() ?

             sumAll(array) :

             defaultSumAll(array);

         // END: design.sidemeanings.arith.the.question

     }

     boolean openUpToSubclasses = true;

     boolean openUpToSubclasses() {

         return openUpToSubclasses;

     }

     // BEGIN: design.sidemeanings.arith.factory

     public static Arithmetica create() {

         return new Arithmetica.Impl();

     }

     private static class Impl extends Arithmetica {

         @Override

         protected int overridableSumTwo(int one, int second) {

             return defaultSumTwo(one, second);

         }

         @Override

         protected int overridableSumAll(int... numbers) {

             return defaultSumAll(numbers);

         }

         @Override

         protected int overridableSumRange(int from, int to) {

             return defaultSumRange(from, to);

         }

     }

     // END: design.sidemeanings.arith.factory

 }

 // END: design.sidemeanings.arith