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Re: Why it necessary to implement clonealbe interface?

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On 11/25/2015 2:01 PM, Eric Douglas wrote:
> On Tuesday, November 24, 2015 at 7:50:28 PM UTC-5, Arne Vajhøj wrote:
>> To this excellent explanation I would just like to add that
>> today (today as in last decade) instead of a marker interfaces
>> one would usually use an annotation. But Cloneable goes back
>> to Java 1.0.
>
> So you think it does just look stupid because it was written into Java 1.0?

I think it looks the way it does because that was the only way in
Java 1.0-1.4 and that it would have been made differently in Java 1.5-.

Nothing stupid really.

> My only other thought for wanting an interface class was to say whether or not you want your cloneable object to return the condition
> if (myObject instanceof Cloneable) {

With annotation you would use:

if(myObject.getClass().getAnnotation(Cloneable.class) != null) {

That in itself does not look like an improvement.

But first it uses the mechanism intended for such thing:
- interfaces specify what methods implementing classes must have
- annotations provide meta-data about class (and other)

It is meta-data not required methods that we need here.

And secondly it provides additional capabilities.

One could define an mode attribute so you could use:

@Cloneable(mode=CloneMode.SHALLOW)

and:

@Cloneable(mode=CloneMode.DEEP)

and access it from the processing code.

Arne

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Thread

Why it necessary to implement clonealbe interface? Xue Feng <xf.lotus@yahoo.com> - 2015-11-24 23:28 +0800
  Re: Why it necessary to implement clonealbe interface? Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-11-24 11:03 -0500
    Re: Why it necessary to implement clonealbe interface? Arne Vajhøj <arne@vajhoej.dk> - 2015-11-24 19:49 -0500
      Re: Why it necessary to implement clonealbe interface? Eric Douglas <e.d.programmer@gmail.com> - 2015-11-25 11:01 -0800
        Re: Why it necessary to implement clonealbe interface? Arne Vajhøj <arne@vajhoej.dk> - 2015-11-25 16:41 -0500
  Re: Why it necessary to implement clonealbe interface? Lew <lewbloch@gmail.com> - 2015-11-29 23:00 -0800

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