From: Cliff Schmidt
Date: May 20, 2005 10:07:56 AM PDT
To: [email protected]
Cc: [email protected]
Subject: Fwd: Proposal for xmlbeanscxx
Hey Axis Folks!
I'm forwarding this proposal for a C++ version of XMLBeans, which is
now being discussed on the xmlbeans dev list. If any of you think
this could be useful to your community, please let us know.
Thanks,
Cliff
---------- Forwarded message ----------
From: Heidi Buelow
Date: May 15, 2005 11:11 AM
Subject: Proposal for xmlbeanscxx
To: "dev at xmlbeans . apache . org"
This is a proposal for an xmlbeans subproject which should be
discussed here
and voted on at the xmlbeans PMC before going to the incubator for
a vote.
Proposal to create a C++ version of the Apache XMLBeans project
Submission date: 15 May 2005, Tim Triemstra, Heidi Buelow (TimT @
RogueWave
dot-com, Buelow @ RogueWave dot-com)
(0) rationale
Apache currently maintains the XMLBeans/Java project, a tool that
uses XML
Schema as a basis for generating Java classes used to easily access
XML
instance data. The goal of the XMLBeans/C++ project is to provide a
very
similar user experience for C++ developers as that provided by the
XMLBeans/Java version. This includes generating strongly-typed C++
classes
for the XML binding as well as providing low-level C++ APIs
enabling access
to the raw, underlying XML content. Where possible, the XMLBeans/C+
+ project
will provide a nearly identical API and parallel architecture to that
provided by the Java counterpart, and will closely mimic both
features and
schedule.
Rogue Wave Software will help jump start this project by
contributing the
existing XML to C++ binding code distributed as part of the LEIF
product to
the Apache community. This product has been in production for over two
years, and will provide a solid foundation for a C++ version of
XMLBeans.
(0.1) criteria
Meritocracy: The C++ version of the project should adhere to the
same open,
merit-based community standards as other Apache projects.
Contributions and Core Developers: Code being contributed is
actually a
subset of the LEIF product. Currently, work is underway to remove any
proprietary dependencies from within the code. A "cleaned" version
that is
ready for contribution will be made available to the community
around the
middle of May 2005. This initial contribution will be fully
functioning, but
missing a few key features of the Java version of XMLBeans.
The community should be able to immediately jump in and begin work,
along
side dedicated Rogue Wave personnel, to turn the initial
contribution into a
feature-compatible version of XMLBeans for C++.
Community: The community around the Java version of XMLBeans is
already
vibrant and growing. There is every reason to believe many of those
within
the existing community have experience and/or general interest in a
successful, compatible C++ implementation of the toolset. This
should ensure
an immediately active and vocal community, even if the primary
interest is
in ensuring a similar experience between versions. There is already
a large
group of developers "in the wild" using the original XML to C++
binding tool
that is serving as the original contribution for this project.
These users
will be migrating to the XMLBeans/C++ code over time and have already
indicated a keen interest in tracking, and even participating in the
Apache-led project.
Apache Alignment: The XML binding tool from which the XMLBeans/C++
port will
morph does not include a full XML parser, but instead uses a small,
focused
parser designed expressly for tight C++ to XML binding support. The
general
purpose XML instance data APIs within XMLBeans will require
additional code
and may be a good fit for the Xerces parser to enable some required
features.
Additionally, at least one member of an existing Apache project has
expressed interest in a project like XMLBeans/C++ to aid in his
current
work. Higher-level projects such as Axis for C++ seem to be natural
beneficiaries of this work.
(0.2) known risks
Orphaned Products: One of the first questions when a commercial entity
offers code to the public is "will this code be abandoned?" To be
clear,
Rogue Wave decided to initiate this process due to its own significant
interest in the XMLBeans feature set already present in Java, and
its need
for similar features in C++. We have significant product goals moving
forward around XML for which the XMLBeans model fits perfectly.
Rather than
simply copy the design and keep the project closed, we felt that the
downstream products would reap significant benefits from opening
the XML
layer to the community. Keeping the C++ version in sync with the Java
version, even if it were to not be accepted as an Apache project,
can only
help its overall adoption.
Additionally, a diverse committer base is a strong goal for this
project.
Numerous users of the contributed XML to C++ binding tool have
indicated
interest in participating, many of whom have critical projects
dependant on
this work and resources available to continue to ensure the
viability of the
project well into the future.
Inexperience with Open Source: Like many companies entering this
arena, we
have limited experience working on open source projects. Our
primary goal is
to foster an active community around XMLBeans/C++ so advice will be
taken to
heart, and significant resources will be dedicated to the project
to get it
off the ground. However, we hope that our experience working in open
standards groups will aid in the transition to the open source
community.
Initial Reliance on Salaried Workers: Due to the rapid process of
transitioning to work on the open source XMLBeans/C++ project, only
a few of
the listed contributors will be outside the commercial realm. We
expect this
list of external volunteers to grow significantly after the initial
public
code drop.
Licensing, Patents, Miscellaneous Legal: We are conducting a legal
review of
the code and existing contracts. This review should be done shortly
and any
code contributed will be licensed under the latest ASF terms.
Commercial Interest: XMLBeans/C++ will be maintained as an open source
Apache project, with all relevant enhancements contributed to the
community.
Additionally, there is every intention to use XMLBeans/C++ within
future
commercial products, thereby resulting in even greater testing and
user
exposure. It is expected that other companies may well wish to use the
project's code within their own commercial endeavors, which of
course would
be fine.
(1) scope of the subproject
The XMLBeans/C++ subproject will conform to the identical scope as
that laid
out for the partner Java project. Special care will be taken to
implement
features and add conveniences that would be expected by a C++
developer.
For clarity, the goals of the XMLBeans/C++ project are:
Generation of plain C++ classes to model XML Schema Validation of C++
objects against the source XML Schema Access to partial document
instance
data (fragments) Efficient "parse as necessary" access that
forgives extra
data Access to the full XML infoset
(2) identify the initial source for subproject code
Some background information may be found on the LEIF product and the
associated Data Tier.
LEIF product page (http://www.roguewave.com/products/leif)
The C++/XML binding contribution code can be found at the following
link:
xmlBeans open source information
(http://www.roguewave.com/opensource/XMLbeans.cfm)
(3) identify the ASF resources to be created
(3.1) mailing list(s)
xmlbeanscxx-dev
xmlbeanscxx-user
xmlbeanscxx-commits
(3.2) SVN repositories
xml-xmlbeanscxx
(3.3) Bugzilla
xml xmlbeanscxx
(4.0) identify the initial set of committers
This is a preliminary list that will be updated with volunteer
members.
Tim Triemstra (TimT @ RogueWave dot-com)
John Hinke (Hinke @ RogueWave dot-com)
Heidi Buelow (Buelow @ RogueWave dot-com)
Allen Brookes (ABrookes @ RogueWave dot-com)
David Haney (David.Haney @ RogueWave dot-com)
Michael Yoder (Michael.Yoder @ RogueWave dot-com)
(5) identify apache sponsoring individual
Cliff Schmidt, of the XMLBeans/Java project, has volunteered to
sponsor this
project.
Cliff Schmidt (CliffS @ Apache dot-org)
(6) open issues for discussion
The original code contribution has a lot of proven code for creating a
binding between XML Schema and C++ classes. However, the
contribution will
require a significant overhaul, and even complete re-writes in some
areas,
in order to reach compatibility with the XMLBeans/Java version.
Detailed
differences will be discussed openly within the community so that an
appropriate plan for each area can be reached. This proposal is not
the best
place to lay out all the technical details, however you will find
below a
preliminary list of issues, priorities, and estimated timelines.
API discrepencies between contributed code and XMLBeans 2.0 The
contributed
code includes a very similar type-binding API in C++ to that
provided in
XMLBeans for Java. However, the XMLBeans cursor access to the
underlying
infoset has no equivilant in the contributed code and will require
extensive
work to the underlying object model to support.
Addressing this deficiency is considered the highest priority task
facing
the C++ project.
Several options are available including porting the XMLBeans object
model
completely over to C++ or looking for ways to augment the
contributed code.
Most likely a near-complete rewrite of this section will be the best
approach.
Rough estimates for a working implementation of the cursor feature are
between three and five months Code generator
The contributed C++ code is based on a proprietary code generator,
although
it too is written in Java (not C++). The long-term plan is to
consolidate
both C++ and Java projects under the same code generator, most
likely the
one already included in the Java version of the XMLBeans.
This is not considered a priority-1 task at this point, more of a
long term
goal and convenience. If it saves time in other priority tasks it
will be
looked at closely, however.
Timeline for this transition is 5-7 months, but may be very much
sooner
depending on available resources.
Platform support
Unlike Java, the C++ port will have significant issues around
platform and
compiler support. In order to help with this the project will be
using the
C++ standard library, and may in fact benefit greatly from the
proposed
Apache C++ StdLib (STDCXX). Initially the native StdLib will be used.
Good platform support will be very important so even the early
builds should
be done on Windows and Linux, and preferably at least one Unix
variety. Long
term the matrix should be very large.
The initial contribution is working on Linux but it is really just
a preview
look at code, not a true product build. Windows and Linux support
should
accompany the initial beta release, with Solaris, HP-UX, AIX, and
other
Linux distros following within three months.
Estimated timeline (very rough)
Initial submission of proposal and example code: 12 May 2005 Apache
structure in place and code building: 1 July 2005 Re-write of internal
object model building: 1 September 2005 XMLBeans/Java 2.0 feature
equivilant
beta: 1 December 2005
This timeline is based on a very preliminary discovery of issues
and is
based on limited resource information. There is little chance for this
schedule to be elongated by very much time as there are already a few
dedicated resources assigned to the project, but there is also
little known
about how much a concerted community effort could speed things up. In
general the feeling is that a greater community involvement will
greatly
improve the test suite, identified bugs, and platform support - not
necessarily the initial speed of feature development.
--------------------
Heidi Buelow
Rogue Wave, a division of Quovadx
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