The Free implementation of CORBA standard

Transcription

1 Content licensed under GFDL The Free implementation of CORBA standard Audrius Meška uskas GNU Classpath

2 Why do we need this?... their need for better integration, rapid development tools, and easier-to-manage systems are drawing them to Windows...

3 What kind of interoperability is provided by CORBA standard? Call remote methods Access server that uses the different OS. Access server that has the different processor. Call the code, written in another language. Send smaller messages without the intermediate text encoding Easily balance the loads CORBA standard was suggested by OMG

4 We needed the implementation that would be: 1. Free, without classes with restricted license. 2. Fully workable, interoperable and pass tests, recognized by the user community as serious 3. Properly commented, being ready for the long life in the Free world. 4. Put no pressure to use the outdated approaches. Jdk We also need a trademark - neutral abbreviation for naming the Free applications that use this implementation.

5 Several Free implementations exist for Java platform. JacORB OpenORB Jonathan Orbas MyORB EJCCM some others None of them seemed matching all our requirements

6 The OMG code segment The problem is that it seems that most ORBs, including Free ones, consider the source code provided by the OMG to be "free enough". This source is under a "freely redistributable but unmodifiable" license.

7 The OMG code segment Web talk: Every single class in the public API is under an unacceptable license. Every single bit of green in the CORBA packages in those oh-so-encouraging Japi results is worthless /pm 18/

8 1. Reimplementing the omg.org We used formal / pdf document. Each of the copyright holders listed above has agreed that no person shall be deemed to have infringed the copyright in the included material of any such copyright holder by reason of having used the specification set forth herein or having conformed any computer software to the specification.

9 2. How to test it properly? We used the CORBA Open Source Testing package (COST), LGPL license. The test were adapted, removing features, not supported by the official API. The tests were converted into the Mauve test form.

10 3. How to comment it? When nobody understands, nobody uses. When nobody understands, nobody improves. Web talk: Complexity (or "It Probably Won't Work")... that if these sites also had to depend on two ORBs being up and running? Netscape hasn't yet figured out how to make a browser that can run a simple Java animation without crashing, but we're supposed to trust the complicated Java ORB that they are putting into their latest browsers?...

11 Bad news: Not all org.omg classes in the Sun 's API have at least some comments

12 Commenting problems OMG formal / has the reputation of the difficult document. Not all classes in Sun's API have at least some comments. In the tested Free projects these classes also were near undocumented Citing

13 There is a solution, how to create a well commented code Solution: write working implementation. In this way the purpose of unclear classes become obvious.

14 What new features appear in the java API versions? 1.2 basic communication over GIOP 1.3 RMI over IIOP (javax.rmi.corba) 1.4 lots of new features: load balancing, request intercepting, servants, DynAnys. 1.5 comparatively minor extensions. Conclusion: if the aim to have 1.4, it is not difficult to have 1.5 as well. This is why we have it.

15 How should we call Free applications, using this GNU Classpath package? CORBA, IIOP and OMG are registered marks. GIOP is not a registered mark and would probably better fit for the Free world because of this reason

16 What is GIOP? General Inter ORB protocol (ORB = Object Request Broker). GIOP IIOP To other interacting systems CORBA

17 The work is now largely done OMG assigns GNU Classpath the Vendor Minor Code Id (VMCID): 0x47430xxx ("GC\x00\x00" - "GC\x0f\xff").

18 Still missing functionality Remote class loading Reason: security Missing tool We still have no our own IDL to Java compiler (but have GIOP stub and tie generator for javax.rmi.corba). Reason: were expected to start as a separate initiatives More documentation and examples needed

19 Sun GNU and Sun playing together GNU Classpath + JamVM

20 Some further ideas SSH, HTTP and other bridges. Get rid of rmic code generator for RMI/IIOP. Support fault tolerant behavior and other CORBA standard features beyond 1.5 java API. Reduce the footprint by constructing trivial classes like single field interfaces on the fly.