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

[Roger Riggs]

Hi,

This feels like a pretty slippery slope; not enough for real terminal 
emulation;
what kind of terminal is it?, etc.  Not enough for jshell/nashorn, which 
imported a whole
package to support command line editing.   (jline - module 
jdk.internal.le/ed)

Regardless, keep it simple! There are very few terminals in the cloud.

On 8/24/18 12:58 PM, Xueming Shen wrote:
> 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" ? :-)
+1
>>
>> 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
>>>
>>
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