Il ven 3 nov 2017, 02:39 Sijie Guo <guosi...@gmail.com> ha scritto:
> Hi Enrico,
>
> In the new ledger api, we return Iterable<LedgerEntry> instead of
> Iterator<LedgerEntry>. In general, it is good to return Iterable, however
> it seems to be problematic in following use case:
>
> Iterable<LedgerEntry> entries = rh.read(...);
>
> Iterator<LedgerEntry> iter1 = entries.iterator();
> while (iter1.hasNext()) {
>
> LedgerEntry le = iter1.next;
> le.getEntryBuffer().release();
>
> }
>
> Iterator<LedgerEntry> iter2 = entries.iterator();
> while (iter2.hasNext()) {
>
> LedgerEntry le = iter2.next();
> le.getEntryBuffer().release();
>
> }
>
> Using Iterable opens up the chance that people will create multiple
> iterators and use them concurrently. I think we should not use
> Iterable<LedgerEntry>, which it might actually cause problems.
>
> I am thinking if we can create an interface LedgerEntries to extend
> Iterable<LedgerEntry>. so:
>
> - the implementation can create increase right buffer reference when
> creating an iterator
> - we can make LedgerEntries a recycleable object, and it is returned to
> the tool when people called #close()
> - on #close(), it releases all the references to release resources
>
> interface LedgerEntries extends Iterable<LedgerEntry>, AutoCloseable {
>
> long getEntry(long entryId);
>
> Iterator<LedgerEntry> iterator();
>
>
> }
>
I think this is a great idea. I remember we already talked about something
similar when we discovered the need to release buffers for v2 protocol but
it was not possible for 4.5.
Enrico
> --
-- Enrico Olivelli
