Groups > comp.lang.java.programmer > #6403

Re: Why "lock" functionality is introduced for all the objects?

Date	2011-07-22 09:45 -0700
From	Patricia Shanahan <pats@acm.org>
Newsgroups	comp.lang.java.programmer
Subject	Re: Why "lock" functionality is introduced for all the objects?
References	(1 earlier) <alpine.DEB.2.00.1106302251380.3024@urchin.earth.li> <4e28c4c4$0$308$14726298@news.sunsite.dk> <j0atr0$vph$2@speranza.aioe.org> <4e298683$0$315$14726298@news.sunsite.dk> <D4Cdna1YPbEkOLTTnZ2dnUVZ_s2dnZ2d@earthlink.com>
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On 7/22/2011 9:30 AM, Patricia Shanahan wrote:
> On 7/22/2011 7:17 AM, Arne Vajhøj wrote:
>> On 7/22/2011 12:20 AM, Henderson wrote:
>>> On 21/07/2011 8:30 PM, Arne Vajhøj wrote:
>>>> On 6/30/2011 6:04 PM, Tom Anderson wrote:
>>>>> On Tue, 28 Jun 2011, Alex J wrote:
>>>>>> The better decision, IMHO, would be to introduce lock/wait mechanics
>>>>>> for only, say, the Lockable descendants.
>>>>>
>>>>> I agree with this, actually. There might be some small performance
>>>>> improvement, but it would also make the locking behaviour of code more
>>>>> explicit, and so clearer.
>>>>
>>>> Given that Java does not allow multiple inheritance then that would
>>>> have been tough restriction.
>>>
>>> Others suggested that Lockable could have been a marker interface with
>>> special significance to the compiler, ala Serializable. Java allows
>>> multiple inheritance of interfaces.
>>
>> It could be, but does that provide any space in the data structure?
>
> Compiler magic. Just as the compiler reacts the lack of any constructor
> by generating a default constructor, it would react to the Lockable
> interface by generating a field to contain the lock data.

More precisely, it would generate the field if the class is Lockable and
its immediate superclass is not Lockable. There should be at most one
lock field in the object.

Patricia

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Thread

Re: Why "lock" functionality is introduced for all the objects? Arne Vajhøj <arne@vajhoej.dk> - 2011-07-21 20:30 -0400
  Re: Why "lock" functionality is introduced for all the objects? Henderson <h1@g1.f1> - 2011-07-22 00:20 -0400
    Re: Why "lock" functionality is introduced for all the objects? Arne Vajhøj <arne@vajhoej.dk> - 2011-07-22 10:17 -0400
      Re: Why "lock" functionality is introduced for all the objects? Patricia Shanahan <pats@acm.org> - 2011-07-22 09:30 -0700
        Re: Why "lock" functionality is introduced for all the objects? Patricia Shanahan <pats@acm.org> - 2011-07-22 09:45 -0700
        Re: Why "lock" functionality is introduced for all the objects? Arne Vajhøj <arne@vajhoej.dk> - 2011-07-22 14:53 -0400
  Re: Why "lock" functionality is introduced for all the objects? v_borchert@despammed.com (Volker Borchert) - 2011-07-22 04:39 +0000
    Re: Why "lock" functionality is introduced for all the objects? Arne Vajhøj <arne@vajhoej.dk> - 2011-07-22 10:19 -0400

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