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