Re: comparison of protected members vs abstract classes

 Daniel Pitts <>
Thu, 20 Sep 2007 21:55:20 -0000
On Sep 12, 5:28 pm, Roedy Green <>

On Wed, 12 Sep 2007 18:57:23 -0000, Sideswipe
<> wrote, quoted or indirectly quoted
someone who said :

I was looking for more discussion on this subject. Any thoughts?

In the example you gave I don't see enough difference to fret over it.
Perhaps with messier examples the difference would become obvious.

With constructors, the specification is positional, terse, but
confusing with a large number of parms.

In both schemes you ensure all data is provided.

I tend to like the abstract method approach. It gives flexibility to
the implementor to use either constructors, constants or complex
Roedy Green Canadian Mind Products
The Java Glossary

If all you want is to encapsulate data, then you might consider using
an Argument object. approach.

final class MyNoLongerBaseClass {
   public static final class Argument {
      // necessary parameters as fields, with getters and setters

   public MyNoLongerBaseClass(Argument argument) {
      // use argument data, throw IllegalArgumentException if its not
configured properly.

From that, you might say, Oh, why don't I just make Argument a Factory

object, that can create my no longer base class objects. Well, the
answer is, you should! You can still have the constructor that
accepts the "Argument" object, but it would only be called from within
the Argument (now called Factory) class.

In this case, using the Builder pattern tends to be useful as well,
allowing chaining of method calls (think StringBuilder/ProcessBuilder)

public class MNLBBuilder {
   public MNLBBuilder someProperty(String value) {
       someProperty = value;
       return this;
   // ... etc...

MNLB mnlb = new MNLBBuilder().someProperty("Foo!").createMNLB();

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