RFR 8056084: Refactor Hashtable to allow implementations without rehashing support

[Coleen Phillimore]

Yes, your new comment is fine.
Coleen

On 8/29/14, 7:17 AM, Mikael Gerdin wrote:
> Coleen,
>
> On 2014-08-29 09:06, Mikael Gerdin wrote:
>> Coleen,
>>
>> On 2014-08-28 23:56, Coleen Phillimore wrote:
>>>
>>> Mikael, Thank you for doing this.
>>>
>>> Can you remove the comments in hashtable.hpp:
>>>
>>>    34 // This is a generic hashtable, designed to be used for the 
>>> symbol
>>>    35 // and string tables.
>>
>> Will do.
>>
>>>
>>> also this comment is outdated so should be removed.
>>>
>>>    38 //
>>>    39 // %note:
>>>    40 //  - TableEntrys are allocated in blocks to reduce the space
>>> overhead.
>>>    41
>>
>> That comment is still correct for callers of
>> BasicHashtableEntry<F>* BasicHashtable<F>::new_entry
>
> I changed it to:
> +// HashtableEntrys are allocated in blocks to reduce the space overhead.
> +template <MEMFLAGS F> BasicHashtableEntry<F>* 
> BasicHashtable<F>::new_entry(unsigned int hashValue) {
> +  BasicHashtableEntry<F>* entry = new_entry_free_list();
> +
>
> Is that ok?
>
> /Mikael
>
>>
>>
>>>
>>> This refactoring looks good.
>>
>> Thanks
>> /Mikael
>>
>>>
>>> Thanks!
>>> Coleen
>>>
>>>
>>> On 8/26/14, 11:26 AM, Mikael Gerdin wrote:
>>>> Hi all,
>>>>
>>>> For JDK-8048268 I need to do some refactoring of the Hashtable class
>>>> template.
>>>>
>>>>  From the bug description:
>>>> In order to simplify usage of the Hashtable<T, F> class the code to
>>>> perform
>>>> rehashing of the SymbolTable and StringTable should be factored out
>>>> to an
>>>> intermediate class common to those two tables.
>>>> Also factor out HashtableEntry freelist allocation to allow
>>>> implementors an
>>>> easier route for providing their own memory management.
>>>>
>>>> Introducing the new intermediary superclass requires some calls to
>>>> superclass
>>>> functions to be qualified using the "this->" syntax due to the C++
>>>> template
>>>> name lookup rules.
>>>>
>>>> a comment about hashtable.cpp RehashableHashtable::dump_table:
>>>>
>>>> -  int bucket_bytes = (int)num_buckets * sizeof(bucket(0));
>>>> +  int bucket_bytes = (int)num_buckets * sizeof(HashtableBucket<F>);
>>>>
>>>> I decided to change the sizeof to count the size of the hashtable
>>>> bucket class
>>>> instead of the HashtableEntry* returned by bucket(0), even though they
>>>> may be
>>>> of the same size currently.
>>>>
>>>> Note that the webrev url refers to another bug.
>>>> Webrev:
>>>> http://cr.openjdk.java.net/~mgerdin/8048268/hashtable-refactor/webrev/
>>>> Buglink: https://bugs.openjdk.java.net/browse/JDK-8056084
>>>>
>>>> Testing: JPRT.
>>>>
>>>