When you don't realize you need a Comparable

[In 2012, I wrote]({% post_url 2012-10-20-replacing-a-hashset-with-a-bitset %}) about how you always learn something new by following the Apache dev mailing lists.

After about five years, I am still learning, and still getting impressed by the knowledge of other developers. Days ago I was massaging some code in a pull request and a developer suggested me to simplify my code.

The suggestion was to make a class a Comparable type to both simplify the code, and also have a better design. I immediately agreed, and looking back in hindsight, it was the most logical choice. Yet, I simply did not think about that.

// What the code was
case VSPACE_SORTKEY :
    int cmp = 0;
    String c1 = nv1.getCollation();
    String c2 = nv2.getCollation();
    if (c1 != null && c2 != null && c1.equals(c2)) {
        // locales are parsed. Here we could think about caching if necessary
        Locale desiredLocale = Locale.forLanguageTag(c1);
        Collator collator = Collator.getInstance(desiredLocale);
        cmp = collator.compare(nv1.getString(), nv2.getString());
    } else {
        cmp = XSDFuncOp.compareString(nv1, nv2) ;
    }
    return cmp;
}

// What the code is now
case VSPACE_SORTKEY :
    return ((NodeValueSortKey) nv1).compareTo((NodeValueSortKey) nv2);
}

This moved the logic to a method in the NodeValueSortKey class. This reduced the complexity of the class with the switch statement. And it also made it easier to write unit tests.

If you are not involved in Open Source projects yet, I keep my suggestion from five years ago. Find a project related to something you like, and start reading the code, lurk in the mailing list or watch GitHub repositories.

You can always learn more!

♥ Open Source

Categories: Blog

Tags: Apache Software Foundation, Java, Opensource, Programming