RFR: 8209937: Enhance java.io.Console - provide methods to query console width and height

[Xueming Shen]

To the core-libs ...

On 8/24/18, 9:56 AM, Xueming Shen wrote:
> Hi Langer,
>
> I would suggest to add explicit wording to emphasize the "size" means 
> the rows
> and columns in characters, not the pixels.
>
> It appears attractive to have a Console.Dimension to abstract the size 
> and make it
> an "atomic" access but I'm not sure if it's really worth the cost to 
> have an extra
> class merely for this purpose. getWidth/Height might be just good 
> enough for most
> possible use scenario for Console class. Maybe we can add a getSize() 
> when we
> have a better abstract/choice later, for example, "tuples/pair" ? :-)
>
> A little background, the design decision of the Console class back 
> then was to avoid
> those platform dependent term curses related stuff, so those size, 
> cursor related
> functionality were purposely removed from the final API and 
> implementation ...
>
> Thanks,
> Sherman
>
> On 8/24/18, 6:41 AM, Peter Levart wrote:
>>
>>
>> On 08/24/2018 03:18 PM, Langer, Christoph wrote:
>>> Hi Rémi, Hi Peter,
>>>
>>> thanks for your quick answers.
>>>
>>> What you've suggested, Rémi, is perfectly right. I've updated my 
>>> webrev. The methods were copied from our old implementation (of a 
>>> different class) where they were provided as static.
>>>
>>> I will also think of using an optional. I'm furthermore wondering if 
>>> we should provide a method "dimensions()" returning an (optional) 
>>> java.io.Console.Dimension object that contains both height and width...
>>
>> Yes, a good idea. In AWT/Swing such methods are called getSize() or 
>> size():
>>
>>     /**
>>      * @deprecated As of JDK version 1.1,
>>      * replaced by <code>getSize()</code>.
>>      */
>>     @Deprecated
>>     public Dimension size() {
>>         return new Dimension(width, height);
>>     }
>>
>> It seems that at some stage, methods like size() have been 
>> @Deprecated and replaced with getSize(). Now we're going back from 
>> getSize() to size() as the preferred name...
>>
>> I suggest you create a private native method that returns both 
>> dimensions (encoded in a jlong for example, with non-existence being 
>> -1L) and then do the conversion (to Optional<Console.Dimension>) in a 
>> public Java method. It would be much simpler than creating objects in 
>> native code...
>>
>> Regards, Peter
>>
>>>
>>> Here is a new webrev: 
>>> http://cr.openjdk.java.net/~clanger/webrevs/8209937.1/
>>>
>>> Best regards
>>> Christoph
>>>
>>>> -----Original Message-----
>>>> From: Peter Levart <peter.levart at gmail.com>
>>>> Sent: Freitag, 24. August 2018 13:06
>>>> To: Remi Forax <forax at univ-mlv.fr>; Langer, Christoph
>>>> <christoph.langer at sap.com>
>>>> Cc: core-libs-dev <core-libs-dev at openjdk.java.net>; Baesken, Matthias
>>>> <matthias.baesken at sap.com>
>>>> Subject: Re: RFR: 8209937: Enhance java.io.Console - provide 
>>>> methods to
>>>> query console width and height
>>>>
>>>>
>>>>
>>>> On 08/24/2018 12:09 PM, Remi Forax wrote:
>>>>> Hi Christoph,
>>>>> getWidth() and getHeight() should be instance methods and not static
>>>> methods, providing the weight or the height if there is no console 
>>>> seems
>>>> weird.
>>>>> Also, they should be named width() and height() given the rest of the
>>>> methods of java.io.Console doesn't use the "get" convention.
>>>>> regards,
>>>>> Rémi
>>>> They could also return OptionalInt to force user to think about
>>>> "not-available" situations.
>>>>
>>>> Regards, Peter
>>>>
>>>>> ----- Mail original -----
>>>>>> De: "Christoph Langer" <christoph.langer at sap.com>
>>>>>> À: "core-libs-dev" <core-libs-dev at openjdk.java.net>
>>>>>> Cc: "Baesken, Matthias" <matthias.baesken at sap.com>
>>>>>> Envoyé: Vendredi 24 Août 2018 11:33:05
>>>>>> Objet: RFR: 8209937: Enhance java.io.Console - provide methods to 
>>>>>> query
>>>> console width and height
>>>>>> Hi,
>>>>>>
>>>>>> please review and give feedback for this augmentation of 
>>>>>> java.io.Console.
>>>>>>
>>>>>> We have users that have the need to query for Width and Height of 
>>>>>> the
>>>> console
>>>>>> device in Java. In our own JVM implementation we had given them this
>>>> hook as a
>>>>>> custom extension already quite some time ago. We think, however, 
>>>>>> that
>>>> it is a
>>>>>> worthwhile augmentation of java.io.Console.
>>>>>>
>>>>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8209937
>>>>>> Webrev: http://cr.openjdk.java.net/~clanger/webrevs/8209937.0/
>>>>>>
>>>>>> I'll also open a CSR for this, but I'll wait for some feedback on 
>>>>>> our proposal
>>>>>> first.
>>>>>>
>>>>>> Thanks & Best regards
>>>>>> Christoph
>>
>