Re: Updates to a single class instance
Thomas Hawtin <usenet@tackline.plus.com> writes:
It's better to write code that doesn't use static variables,
whether Singletons or not. That is easier if the code is
coherent.
The first Java-Program a programmer encounters:
public class Main
{ public static void main( final java.lang.String[] args )
{ java.lang.System.out.println( "Hello world!" ); }}
uses a static variable ?out?.
To avoid it, we might need a new Java with:
public class Main
{ public static void main( final System system )
{ system.out.println( "Hello world!" ); }}
Then, ?system? needs to be passed to many methods and
constructors, whereever it possibly might be needed.
Or private static variables with static get/set methods. That
is to all intents and purposes the same thing as a singleton,
only there is no pretend OO.
An example would be the getter:
java.lang.Thread.currentThread()
It is not the same as a singleton, because there is no
intention that the result is the /only/ instance of its
class.
To avoid it, we'd need to pass another object, because,
logically, the current thread is not a system property.
public class Main
{ public static void main( final System system, final Thread currentThread )
{ system.out.println( "Hello world!" ); }}
This also would have to be passed to every method that
possibly might need it some day or otherwise many signatures
will need to change in order to add it as a parameter.