[Olap4j-devel] [Mondrian] Convert Connection to OlapConnection

Julian Hyde jhyde at pentaho.com
Tue Apr 6 19:49:24 EDT 2010


I stand by the comments I made in that forum post. MdxParser is part of
olap4j's public API, but DefaultMdxParserImpl is not and will never be.
 
http://www.olap4j.org/api/org/olap4j/mdx/parser/package-summary.html
 
The public API, remember, is for people building OLAP applications. To them,
olap4j needs to look like JDBC, but with one exception. JDBC drivers don't
supply a SQL parser, but parsing is more important to MDX applications so
every olap4j driver must supply an MDX parser that implements the MdxParser
interface.
 
The other important audience is developers of drivers. To a limited extent,
the olap4j code base gives them an SPI to help them build drivers.
DefaultMdxParserImpl is part of that SPI, as are the classes in
org.olap4j.impl. We will try to keep the SPI stable as olap4j eveolves but
we won't bust a gut over it.
 
Remember that different drivers might be talking to different OLAP engines,
and different engines have different dialects of MDX, so naturally the
driver writers might want to create their own parser. They can write a
parser from scratch, or they can start with the default MDX parser.
 
If you want to dismember the olap4j project to get the MDX parser, then go
ahead. olap4j is after all an open source project. But you're on your own.
You are in a small minority of olap4j users, and we don't intend to change
the olap4j API for your benefit.
 
It sounds like 
 
Julian
 


  _____  

From: Luc Boudreau [mailto:lucboudreau at gmail.com] 
Sent: Tuesday, April 06, 2010 3:58 PM
To: Mondrian developer mailing list
Cc: olap4j-devel at lists.sourceforge.net
Subject: Re: [Olap4j-devel] [Mondrian] Convert Connection to OlapConnection



As of olap4j revision 307 (
http://olap4j.svn.sourceforge.net/viewvc/olap4j?view=rev
<http://olap4j.svn.sourceforge.net/viewvc/olap4j?view=rev&revision=307>
&revision=307 ) the default MDX parser does not depend on OlapConnection. It
should not have been dependent on it in the first place. 

Mondrian developers: please modify the olap4j connection implementation and
remove the now deprecated call to DefaultMdxParserImpl(OlapConnection).
Modifications to the generic XML/A driver have already been performed.

This does not mean that DefaultMdxParserImpl is part of the public API yet.
There should be a default parser factory exposed to developers. In the
meanwhile, developers can directly instantiate it, but be advised that we do
not provide any guarantees on this object's signature and we reserve the
right to modify it in the future. To create a parser, developers can call
the empty constructor.

A compiled binary which includes those changes can be picked from the CI
server as of now :

http://ci.pentaho.com/view/Analysis/job/olap4j/258/

_____________________________
Luc Boudreau



On Tue, Apr 6, 2010 at 5:38 PM, Luc Boudreau <lucboudreau at gmail.com> wrote:



This topic was discussed in olap4j forums.

http://sourceforge.net/projects/olap4j/forums/forum/577988/topic/3545015

Although Julian's last comment mentioned that the parser is not officially
part of the public API, I for one would like to make it part of the public
API. There are many use cases for it and your request confirms it.

I'll see what I can do to detach the parser from the connection classes.

_____________________________
Luc Boudreau



On Tue, Apr 6, 2010 at 5:32 PM, Josh Chappelle <jchappelle at 4redi.com> wrote:


Hi,

 

We have a need to use the MdxParser component from the Olap4j project.
However up until this point we have not been using olap4j at all. To
instantiate a DefaultMdxParserImpl you have to provide an
org.olap4j.OlapConnection object in the constructor. Our software is using a
mondrian.olap.Connection. Is there a way to convert between these two
connection objects? If not does it mean that we will have to use the
org.olap4j.OlapConnection in order to use the MdxParser?

 

Thanks,

 

Josh 


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