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Subject: Re: [ApacheDS] how can a partition return more than one result ?
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 <4FD1E8D9.80409@gmail.com>
From: Garbage <garbage@gmx.de>
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Date: Fri, 8 Jun 2012 14:05:57 +0200
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Am 08.06.2012 um 13:58 schrieb Emmanuel L=C3=A9charny <elecharny@gmail.com>:=


> Le 6/8/12 1:49 PM, Garbage a =C3=A9crit :
>> I learned a lot about the implementation of custom partitions and see the=
 changes in the API from search and lookup returning an Entry in 1.5.x and a=
n EntryFilteringCursor later on.
>> I even was able to change an existing partition (shame on me: based on th=
e 1.5.5 example, but I will switch to 2.0 soon) in a way that lets it return=
 a fake group object that was created in my custom POJO.
>>=20
>> But I am only able to return ONE entry, I didn't find or understand the c=
oncept how MULTIPLE entries can be returned. Can someone show me the right d=
irection ?
> The idea is to use a Cursor that maps around the partition and fetch the e=
ntries one by one.
>=20
> The way the server works is that based on your filter, you select the righ=
t index to use to fetch the entries. There are may possibilities here :
> - first, you may have to do a full scan (the filter is not selective enoug=
h, for instance). In this case, you don't use any index, you just use the Ma=
sterTable to get the entries. Now, for each entry you fetch, you'll have to f=
ilter them to see if it's a valid entry - or not.
> - or you can select an index. You will fetch the index elements, and for e=
ach of them, fetch the associated entry.  Once done, you can check against t=
he filter if the entry is valid - or not
>=20
> In any case, the cursor is your friend here : it maps the next() operation=
 on top of your index.
>=20
> Now, if your Partition is a Btree, it's easier, as the AbstractBTreePartit=
ion class already handles everyting for you. If you don't inherit from this A=
bstract class, then it's way more complicated. I'll suggest you have a look a=
t the AbstractBTreePartition to get a clue about how we process a search ove=
r a BTree based partition.
>=20
> --=20
> Regards,
> Cordialement,
> Emmanuel L=C3=A9charny
> www.iktek.com
>=20

Thanks, I will investigate this. What a pity, I am able to map searches to s=
tring arrays containing the name of groups I want to return. But I understan=
d why you don't support arrays directly, I will somehow manage to map to the=
 Bree example. And if not I will show up here again ;-)