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Opensource API beta including a MIDP2 midlet

 
serge masse
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Version 0.7 of the Leafy API and its demo Leafyseadragon are released
at http://leafy.dev.java.net/
The downloadable files are in the *File sharing* section of the project; the link is in the left-hand side of the home page. V.0.7 also contains the Leafyseadragon demo, version 0.3.
Leafy version 0.7 has some known defects to be corrected in the next release (0.7.1). The readme file has yet to be written for this release.
The demo has been tested with file run.bat (in leafyseadragonj2se/run) for Windows using configuration file c_standalone.properties and with the MIDP 2.0 MIDlet running in the J2ME Wireless Toolkit (WTK20) from Sun, on the same computer (Windows XP). The demo uses the thinlet API for the H node gui (a J2SE 1.4 component).
The tested demo configuration is for rapid testing with the 3 backbone nodes (H, C2H, and C) on the same host.
To run the demo in the basic configuration (standalone):
1. start the 3 backbone nodes (on the same host): run file run.bat in the leafyseadragonj2se/run directory.
2. optionnally run the MIDlet in the simulator (WTK20) from Sun Microsystems: create a project in your version of the simulator, copy the J2ME (tm) source code of the demo in the project, build the application, run it. You could also run the MIDlet in a MIDP2 device such as a Sony Ericsson P900.
3. The 3 predefined signals that can be used in the demo are: signal1, signal2, and signal3.
With the Leafy api, a Java developer can more quickly write a socket-based distributed application that includes non-Java, or J2SE, as well as J2ME MIDP 2 nodes on mobile devices such as the Motorola A760 Linux smart phone (when equipped with a MIDP2 runtime, e.g., from esmertec or IBM) or the Sony Ericsson P900 (which contains the Symbian MIDP2-capable runtime).
The Leafy api contains much code to help make the distributed application usable by the general public (i.e., non technical users).
Using sockets and XML for communication, the application may include nodes developed with other languages than Java.
I need feedback on Leafy and on Leafyseadragon.
Thanks,
serge
 
Michael Yuan
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Originally posted by serge masse:
Using sockets and XML for communication, the application may include nodes developed with other languages than Java.

Hi Serge,
I have not tried Leafy. But aren't Jabber and JXTA both make use of this XML-over-sockets idea as well? What is the advantage of the new P2P framework?
cheers
 
serge masse
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Originally posted by Michael Yuan:

I have not tried Leafy. But aren't Jabber and JXTA both make use of this XML-over-sockets idea as well? What is the advantage of the new P2P framework?
cheers

Hi Michael,
excellent question.
I'll be brief in this reply and can explain further later if needed.
1) Jabber appears to be a pure chat application, it has a very interesting design and I did consider it in 2002, but I did not want to limit Leafy to a chat-like topology, and I did not want the API to require a server for the application using it, and Jabber appears to require servers. It did provide confidence in my early design to observe that Jabber was operational. Leafy is a pure decentralized, p2p, distributed framework, although the application using it may be somewhat centralized. For example, the Leafyseadragon demo for Leafy is a p2p network that contains 3 backbone nodes that must be present in this application and that may be considered to be servers from the users point of view. So Leafy can be used to develop servers components also, but it does not require servers.
2) JXTA: I did try hard to use JXTA 1.x and I did write some prototypes on top of it in 2002, before JXTA 2 came along, but was disappointed by some of the limitations of the 1.x implementation. It was nevertheless very useful in helping me to finalyze the requirements for my early API. I am hoping to use at least some JXTA protocols in future versions of Leafy and ideally in Leafy 1.0, e.g., the universal node id is nice. I have yet to try and look at JXTA 2's code, which is very interesting and seems to contain many of the features that I needed in 2002. Integrating JXTA 2 in Leafy is a priority of the Leafy open-source project on java.net.
thanks,
serge
 
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