PriorityQueue

[Stuart Marks]

Hi Martijn/Ben/Mani,

Thanks for volunteering to help out Brett via the AdoptOpenJDK effort.

Hi Brett,

Thanks for picking this up. This is indeed an omission in the JDK and it would 
definitely be an improvement if this were added.

Also note this has gotten a bit confusing, as there is a parallel thread on 
core-libs-dev at openjdk.java.net. I'd suggest that further discussion take place 
there. (Setting Reply-To on this message; we'll see if that has any effect.)

Thanks.

s'marks

On 5/14/15 11:11 AM, Martijn Verburg wrote:
> Hi Brett,
>
> You can ask over at adoption-discuss about process, build etc. It is the
> case at times where doing the work to produce a patch is just a starting
> point for a discussion (it can be easier to discuss concrete code rather
> than abstract ideas).  One of the key things would be to have one of the
> core committers of jdk9 and/or core-libs respond on this thread as well
> (see jdk9 & core-libs membership at  http://openjdk.java.net/census#members).
> Also I'd search the archives for any previous discussions on this topic
> (possibly under core-libs as well).
>
> Cheers,
> Martijn
>
> On 14 May 2015 at 17:49, Brett Bernstein <brett.bernstein at gmail.com> wrote:
>
>> Thank you for the encouragement.  I wanted to make sure I wasn't missing
>> something silly before learning how the submission process works, how to
>> build the JDK on my machine, signed agreements, etc.  I will hopefully be
>> able to start down that road soon assuming my schedule accomodates.
>>
>> -Brett
>>
>> On Thu, May 14, 2015 at 12:01 PM, Ben Evans <benjamin.john.evans at gmail.com
>>>
>> wrote:
>>
>>> That sounds entirely plausible & will be of interest.
>>>
>>> Do you have a patch the community can review & contribute to?
>>>
>>> Thanks,
>>>
>>> Ben
>>>
>>>
>>> On Fri, May 15, 2015 at 12:52 AM, Brett Bernstein
>>> <brett.bernstein at gmail.com> wrote:
>>>> My motivation is essentially what you stated.  If someone needs to
>> make a
>>>> heap and their data is Comparable, the corresponding constructor gives
>> a
>>>> O(n) runtime.  If their data uses a Comparator, the corresponding
>> runtime
>>>> (using addAll) is O(n*log(n)).  It is true they will need to copy the
>>> data
>>>> into an array to use it (as initElementsFromCollection does), but that
>> is
>>>> unavoidable.
>>>>
>>>> On Thu, May 14, 2015 at 11:35 AM, Vitaly Davidovich <vitalyd at gmail.com
>>>
>>>> wrote:
>>>>
>>>>> What I mean is what could the PQ do more efficiently with your
>>> Collection
>>>>> vs you manually add()'ing each method? Are you looking to exploit the
>>> same
>>>>> behavior in its PriorityQueue(Collection), i.e. add and then heapify
>> in
>>>>> bulk? initElementsFromCollection() doesn't seem all that efficient in
>>> the
>>>>> first place if one were to invoke this on fast paths.
>>>>>
>>>>> On Thu, May 14, 2015 at 11:27 AM, Brett Bernstein <
>>>>> brett.bernstein at gmail.com> wrote:
>>>>>
>>>>>> I may not understand what static method you are suggesting.  If you
>>> have
>>>>>> a collection containing data and you wish to make it into a
>>> PriorityQueue
>>>>>> using a Comparator, there is no efficient method at the moment
>> (addAll
>>>>>> doesn't work).
>>>>>>
>>>>>>
>>>>>> On Thu, May 14, 2015 at 10:11 AM, Vitaly Davidovich <
>> vitalyd at gmail.com
>>>>
>>>>>> wrote:
>>>>>>
>>>>>>> What would be the intrinsic advantage of such a constructor? Why
>> not a
>>>>>>> simple static util method in your own code that emulates this?
>>>>>>>
>>>>>>> sent from my phone
>>>>>>> On May 14, 2015 1:17 AM, "Brett Bernstein" <
>> brett.bernstein at gmail.com
>>>>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> To whom this may concern:
>>>>>>>> I believe the list of PriorityQueue constructors has a glaring
>>> omission
>>>>>>>> that could be easily rectified.  That is, there is no constructor
>>> that
>>>>>>>> takes a Collection and a Comparator.  What steps should I go
>> through
>>> to
>>>>>>>> get
>>>>>>>> this suggested to be added to the class?
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Brett Bernstein
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>
>>