JInterface

Sean Hinde <>
Tue Jan 9 20:37:05 CET 2001


When faced with this problem here (interfacing business system to Erlang
system) we looked at:

CORBA - concluded it was overkill

Jinterface - The Java guys here couldn't quite figure out how to make it run
asynchronous - and didn't want to take on lots of "proprietary ericsson Java
code" apparently. In your case it doesn't seem to be an option.

Simple wireline protocol over a raw socket stream - I use a simple LF
terminated protocol to talk from an Applet into an erlang gen_server - ok,
but a bit grubby and low level. A feasible option and very easy in Erlang
:-).

XML over HTTP - this is what we chose. The Java side sends Erlang a HTTP
POST containing some XML with the data. Erlang responds with an XML result.
It's not very efficient but it does work and is quick to implement and
change.

I also saw something somewhere about a sun rpc implemenmtation for Erlang

And I head of someone implementing a SOAP interface pretty easily (in effect
XML over HTTP)

- Sean

> -----Original Message-----
> From: Francesco Cesarini [mailto:]
> Sent: 9 January 2001 19:12
> To: Ciaran Johnston; 
> Subject: Re: JInterface
> 
> 
> > Thus all we need is for the syntax of the messages to be
> > consistent from R5B to R7B (at least that is what we are hoping). Is
> > this the case?
> 
> Nope.. Does not work, as there are also changes and 
> improvements in the
> Erlang distribution among releases, different versions of 
> Erlang can not
> talk to each other (Unless of course, the distribution went 
> untouched..
> Which is definitively not the case between R5 and R7).
> 
> 
> I'm going home!
> 
> Ciao,
> Francesco
> 
> > 
> > Chris Williams wrote:
> > >
> > > Hi Ciaran,
> > > If you use R5B you havce to use jinteface (R5B) for it....
> > > If you use R7B you should use jinteface (R7B) for it....
> > > One can not coppy files from R7B to R5B this will not work and
> > > will not be supported by erlang/OTP and probably will not work!
> > > Ciaran Johnston wrote:
> > > >
> > > > Hi,
> > > >         I am looking at ways of interfacing a java 
> application with an Erlang
> > > > node, and one of the better options appears to be 
> JInterface. However
> > > > the situation we want to use it in offers a few 
> possible sticking
> > > > points. Here's the lowdown:
> > > >
> > > > The Java application is running on a different system 
> to the one running
> > > > the Erlang node(s). We want to be able to communicate 
> from this system
> > > > to many other systems running an Erlang node. We don't 
> want to have
> > > > Erlang in any form installed on the system running the 
> Java. We came up
> > > > with this solution: to copy the Java source files from 
> the R7B source
> > > > code and build the JInterface application locally, on 
> the relevant
> > > > machine. We have done this but haven't managed to test 
> it yet - we've
> > > > had no end of software configuration problems. Can 
> anyone anticipate a
> > > > problem with this?
> > > >
> > > > Our other problem, a more worrying one, is the 
> compatibility between R7B
> > > > and R5B - the Erlang nodes are all running R5B. Are there any
> > > > compatibility issues between these two versions bearing 
> in mind that we
> > > > are only using JInterface to send messages between the 
> Java application
> > > > and the Erlang node? In other words, can we do what we 
> are trying to do?
> > > > As I mentioned, we haven't been able to test it here yet.
> > > >
> > > > Thanks in advance,
> > > >
> > > > Ciaran.
> > >
> > > --
> > > 
> ====================================================================
> > > Christopher Williams Phone:    +353 902 31365
> > > Ericsson Systems     ECN:      83021365
> > > Expertise Limited,   Mob:      +353 87 64 888 04
> > > Athlone,             Fax:      +353 902 31304
> > > Co.Westmeath,        http://nosc.eei.ericsson.se/pdu_access/Lynx
> > > Ireland              
> > > 
> ====================================================================
> > 
> > --
> > Ciaran Johnston
> > Ericsson Systems Expertise Ltd.,
> > Athlone
> > Co. Westmeath
> > Eire
> > 
> > email: 
> > Phone: +353 902 31274
> 
> -- 
> Francesco Cesarini
> 
> Erlang/OTP consultant
> Cellular: INT+44-7776 250381 
> ECN: 832-707192
> http://welcome.to/cesarini.consulting
> 



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