Le 3/28/12 5:31 PM, Alex Karasulu a écrit :
On Thu, Mar 22, 2012 at 8:38 PM, Emmanuel Lécharny<elecha...@gmail.com>wrote:
Hi,
one last mail...
I will just mention that we alreadu discussed this mater (ie should we
keep oneLevel and sublevel index) last year with Stefan, and he thinks that
we can get rid of those two guys :
http://mail-archives.apache.**org/mod_mbox/directory-dev/**
201110.mbox/%3CCAPz8h_**WfA2Wa2iZpSdwSswKGoFw9aun1---**
pUvorVpduSLKFgQ@mail.gmail.**com%3E<http://mail-archives.apache.org/mod_mbox/directory-dev/201110.mbox/%3ccapz8h_wfa2wa2izpsdwsswkgofw9aun1---puvorvpduslk...@mail.gmail.com%3E>
and
http://mail-archives.apache.**org/mod_mbox/directory-dev/**
201110.mbox/%3CCAPz8h_**VTUQKRtgaN4QZ+**4PX3KJTu6DPPjAw6k9roMXvnD7Ok_**
q...@mail.gmail.com%3E<http://mail-archives.apache.org/mod_mbox/directory-dev/201110.mbox/%3ccapz8h_vtuqkrtgan4qz+4px3kjtu6dppjaw6k9romxvnd7o...@mail.gmail.com%3E>
No need to rehash them, it's probably time to get the branch merged with
the trunk?
We should review this then proceed accordingly.
So, I have made progress !
Stefan's idea was to add markers (ParentIdAndRdn with RDN : zzz=zzz) in
the index, to be able to find the children.
This is not even needed, as soon as each element knows how many children
it has.
What I did was to add such an information in the ParentIdAndRdn class,
information which gets updated every time we add/remove/move an entry,
and to use it while browsing the index.
The thing is that a Table contains couple of <Key, Value(s)> (Values if
the Table allows duplicates, which is not the case for the RDN index).
We can get a cursor on this table, and set a position in it (the
position being the first element *before* one given as a marker).
Let's suppose we have such a hierarchy :
<root>[0]
|
+-- <0, cn=A>[1]
|
+-- <1, cn=B>[2]
|
+--<1, cn=A>[3]
The forward index will be :
<0, cn=A> : 1
<1, cn=B> : 2
<1, cn=A> : 3
and the reverse index :
1 : <0, cn=A>
2 : <1, cn=B>
3 : <1, cn=A>
So I get a cursor, and considering we are looking for, say, all the
children for cn=A, which ID is 1, I asked the cursor to be positionned
before <1, null>, where 1 is the ID for the cn=A element.
Now, I can fetch the context entry and ask how many children it has.
Here, it has 2. I just have to browe the tree starting at the given
position (ie, cn=A), and browse the tree until I have fetched 2
elements. The cursor will return <1, cn=B> and <1, cn=A> which are the
children of <0, cn=A>.
How do I get the browser to fetch the element in the right order ? It's
easy : the ParentIdAndRdn class has a compareTo() method which is used
to compare two instances. I just modified it so that if the ID are not
equals, then I don't even bother using the RDN. If ID1 = 7 and ID2 = 10,
then the two instances are not common children of an entry. OTOH, if the
two instances ID are equals, then that means they have the same parent.
In this case, in order to insert the elements in the ordered tree, the
RDN is used to inject the new instance in the right place in the tree.
It works well for the OneLevel scope, and it will also work well for the
sub-level, except that we will need to use a recursive call for each
found children.
I will continue my experiments in the index branch, I've not yet removed
the oneLevel and sublevel indexes...
More to come !
--
Regards,
Cordialement,
Emmanuel Lécharny
www.iktek.com
