Hi Marcel,
thank you for your fast response! Reading your response i realized that
i forgot some points in my last mail.
Am 06.08.2013 14:37, schrieb Marcel Offermans:
Hello Elmar,
On Aug 6, 2013, at 13:19 , Elmar Zeeb<[email protected]> wrote:
i'm looking into apache ace to check if i can use it as backend for a web based
market to install software extensions on an osgi based application. In this use
case i can't use the vaadin based ui but started to implement a java based
client for the client REST API.
Underneath the Vaadin, REST and (very recently) GoGo client API's lies the same Java
Client API. In other words, that's a good place to start with your own client. In this
case, the "Workspace" class that is an abstraction on top of that (part of the
REST client) can be used to start.
I didn't mention that my client can't run inside apache ace, but should
use a remote api.
The next point is, that i can't use osgi to run the client.
From my explorations the java client api can run remotely but depends
on osgi. That's why i looked at the REST API first.
I'm aware of the amdatu ace client, but i wanted to implement a client on my
own to understand the api and apache ace. Currently i'm able to create, modify
and delete different client resources (artifact, feature, distribution and
target) but have problems with associations. I have looked at the client rest
api docu on ace.apache.org and athttps://issues.apache.org/jira/browse/ACE-151
to get a better understanding of associations filters and queries.
Ok.
I don't understand how to set the leftEndpoint and rightEndpoint attributes of
associations. As written on the web site these attributes are LDAP filters.
Does this mean that i have to parse the LDAP filter on the client side to check
which resources are associated?
Yes, they are LDAP filters.
No you don't need to parse them yourself, that is something the associations
will do for you. Just provide the filter condition and it will be evaluated
against objects on the left or right hand side of the association.
Is there a way to let ace do the filtering and return resource ids? I'm aware of
the ace/clients/tmp/9876/artifact2feature?left=&right=query. Is there something
like ace/clients/tmp/9876/artifact2feature/12345/leftResourceIdsto query all left
resource ids of an association?
If you create an association, you can set the left and right hand filters
yourself.
The vaadin UI uses attribute based LDAP filters to create associations. I would like to
have static associations based on resource ids - so i use LDAP filters like
"(id=[resource id])" to specify endpoints.
Take a look at the Workspace.cas() method (a generic way to create an
association) where you can do something like:
ws.cas("distribution2target", "(name=foo)", "(id=bar)");
I setup the ace rest client to run in a debugger and found out, that
setting "leftEndpoint" and "rightEndpoint" attributes during association
creation does not work. The associations are created successfully but
the ldap filters are not used to associate resources. That may be the
cause why the vaadin ui doesn't show this associations.
Now I set "left" and "right" attributes. If I use ressource ids for left
and right ace automatically fills in corresponding ldap filters for
leftEndpoint and rightEndpoint. So setting leftEndpoint and
rightEndpoint attributes directly doesn't seem to work.
Optional arguments to specify the cardinality can be used to force ACE to use a
1:1 (or 1:N, N:1 or N:N) cardinality.
The vaadin ui can't display these associations.
Actually, if you click on some object, it will always highlight everything that
is associated, even if you do it via these programmatically created
associations.
My programmatically created associations with leftEndpoint and
rightEndpoint attributes don't show up in the vaadin ui, but
associations with left and right attributes show up in the vaadin ui -
problem solved.
ACE-151 mentions that there are no checks for LDAP filters so the filter may
not work.
So my question is how to specify association endpoints and how to query
resource ids of associates resources with the client REST API?
My advice is to use the Java API. If you have an Assocation object, you can
simply ask it to getLeft() or getRight() and you will get a list of all
associated objects on either side.
So now I have a working client for 1:1 associations as I can read the
left and right attribute of associations. But when I use 1:n
associations i can't easily get the list of related objects - besides
using the java api. I'm looking for query similar to getLeft() and
getRight() in the REST API. Is there something similar? Or does the left
and right attribute contain a list of resource ids in this case ?
When i was debugging the rest api i also saw that the target resource as
special operations: register and approve.
I can imagine what these operations do, but how do i call them ?
At the moment i register a target by recreating a target resource and
unregister the a target by deleting a target resource. But i have no way
to approve changes without setting the auto approve attribute.
Regards,
Elmar
