Foreign Function Calls to Java
What provisions does LispWorks make for calling Java functions? What solutions have people found useful and effective?
What provisions does LispWorks make for calling Java functions? What solutions have people found useful and effective?
John C. Mallery wrote: >What provisions does LispWorks make for calling Java functions? > >What solutions have people found useful and effective? > > > Two theoretical paths are: (1) Java JNI -> LispWorks FLI (ie via C). You use javah to generate ..c/.h files that define the Java interface and then use the LispWorks FLI generator to convert those into definitions you can call from Lisp. You probably have to write some extra glue code too. You have to load the JVM into LispWorks. (2) Java-to-IDL -> IDL-to-Lisp (ie via CORBA). Unlike all other languages with a CORBA binding, Java has a reverse mapping to IDL (normally the mapping are from IDL to the language). So you could generate the IDL description of your Java interfaces and then use the IDL to generate Lisp code that will call that. You may also need to write some extra glue code. PROs and CONs (1) is more efficient (2) would enable you to dynamically choose whether to load the JVM runtime into LispWorks or run it as a separate executable (2) would enable you to run the processes remotely from each other on different machines (2) would enable you to change the implementation language of either end more easily __Jason
I am nearing completion of jfli - a fairly extensive interface to Java from
LispWorks, which I intend to release as open source under the Common Public
License.
The approach I took was to embed a JVM instance in the Lisp process using
JNI. I was able to do this using LispWorks' own FLI and no C (or Java! *)
code, which is a tribute to the LW FLI. On top of the JNI layer (essentially
a wrapper around the entire JNI API), I built the user-level API using Java
reflection.
My objective was to provide comprehensive, safe, dynamic and Lisp-y access
to Java and Java libraries as if they were Lisp libraries, for use in Lisp
programs, i.e. an emphasis on working in Lisp rather than in Java.
jfli ("jay fly") provides:
Automatic function generation for constructors, fields and methods, either
by named class, or entire package (sub)trees given a jar file.
Java -> Lisp package and name mapping with an eye towards lack of surprise,
lack of conflict, and useful completion
setf-able setter generation for fields as well as for methods that follow
the JavaBeans property protocol
Java array creation and aref-like access to Java arrays
A 'new' macro that allows for keyword-style field and property
initialization.
Typed references to Java objects with an inheritance hierarchy on the Lisp
side mirroring that on the Java side - allowing for Lisp methods specialized
on Java class and interface types.
Implementation of arbitrary Java interfaces in Lisp, and callbacks from Java
to Lisp via those interfaces. (* this required a single 5-line dummy Java
proxy stub, provided with jfli)
Automatic lifetime maintenance of Lisp-referenced Java objects,
boxing/unboxing of primitive args/returns, string conversions, Java
exception handling, overload resolution etc.
I built jfli using LWM and LWW (using Apple's and Sun's JVMs respectively),
and it works fine on both. Should be a trivial port to other LispWorks, and
a possible port to any Common Lisp with a robust FLI. Should also work with
any JVM with a conformant JNI implementation.
-----Original Message-----
From: owner-lisp-hug@xanalys.com [mailto:owner-lisp-hug@xanalys.com] On
Behalf Of John C. Mallery
Sent: Wednesday, June 23, 2004 6:55 AM
To: lisp-hug@xanalys.com
Subject: Foreign Function Calls to Java
What provisions does LispWorks make for calling Java functions?
What solutions have people found useful and effective?
On Wed, 23 Jun 2004 09:50:45 -0400, "Rich Hickey" <rich@richhickey.com> wrote:
> I am nearing completion of jfli - a fairly extensive interface to
> Java from LispWorks, which I intend to release as open source under
> the Common Public License.
>
> The approach I took was to embed a JVM instance in the Lisp process
> using JNI. I was able to do this using LispWorks' own FLI and no C
> (or Java! *) code, which is a tribute to the LW FLI. On top of the
> JNI layer (essentially a wrapper around the entire JNI API), I built
> the user-level API using Java reflection.
>
> My objective was to provide comprehensive, safe, dynamic and Lisp-y
> access to Java and Java libraries as if they were Lisp libraries,
> for use in Lisp programs, i.e. an emphasis on working in Lisp rather
> than in Java.
>
> jfli ("jay fly") provides:
>
> Automatic function generation for constructors, fields and methods,
> either by named class, or entire package (sub)trees given a jar
> file.
>
> Java -> Lisp package and name mapping with an eye towards lack of
> surprise, lack of conflict, and useful completion
>
> setf-able setter generation for fields as well as for methods that
> follow the JavaBeans property protocol
>
> Java array creation and aref-like access to Java arrays
>
> A 'new' macro that allows for keyword-style field and property
> initialization.
>
> Typed references to Java objects with an inheritance hierarchy on
> the Lisp side mirroring that on the Java side - allowing for Lisp
> methods specialized on Java class and interface types.
>
> Implementation of arbitrary Java interfaces in Lisp, and callbacks
> from Java to Lisp via those interfaces. (* this required a single
> 5-line dummy Java proxy stub, provided with jfli)
>
> Automatic lifetime maintenance of Lisp-referenced Java objects,
> boxing/unboxing of primitive args/returns, string conversions, Java
> exception handling, overload resolution etc.
>
> I built jfli using LWM and LWW (using Apple's and Sun's JVMs
> respectively), and it works fine on both. Should be a trivial port
> to other LispWorks, and a possible port to any Common Lisp with a
> robust FLI. Should also work with any JVM with a conformant JNI
> implementation.
Wow, that sounds cool! I'm looking forward to that.
Edi.
On Jun 23, 2004, at 9:50 AM, Rich Hickey wrote: > I am nearing completion of jfli - a fairly extensive interface to Java > from > LispWorks, which I intend to release as open source under the Common > Public > License. > This sounds really good. Sorry, but I have to ask... What do you think the timing is on this? Do I understand what you are saying properly? LW using jfli starts a jvm, can create a bunch of objects, call methods on those objects, implement Java interfaces so can set up lisp handlers for callbacks in a gui say, or a web application, which themselves can call back into Java. What happens across invocations of the LW program -- lisp has an image which can be re-started, Java doesn't? Let me tell you, I'd be happy to have such problems :-) I'm also curious what your intended use is for this... what problem are you trying to solve? Cheers, Bob
I hope to have a beta up on SourceForge within a month. Yep, Lisp starts the JVM, you create objects, can fire up a GUI and receive events. I've successfully called JDBC and SWT (some Mac hiccups, Windows OK) so far. It can load any classes, as normally done in Java, so is not limited to the core Java API. Extending the Lisp image notion to Java is beyond the initial scope of the project. For all the dynamism of Java class loading etc, the VM loading support in JNI is fairly rigid (one JVM instance, no unloads, no restarts etc). So Java is inferior to Lisp in that regard, but still useful. What I'm trying to do is increase the practicality of Lisp (for me, personally, I know it's quite powerful on its own), for a wide variety of projects. I'm interested in SWT as a portable UI for Lisp (no slight to CAPI, a very nice library); better integration with the outside world; access to vast libraries of stuff I'd rather not roll on my own. I want to do more real-world work in Lisp and not spend a lot of time wheel-reinventing while doing so. With jfli, Lisp will always have a library that is a superset of Java's, and everyone working on libraries for Java is working on libraries for Lisp. -----Original Message----- From: owner-lisp-hug@xanalys.com [mailto:owner-lisp-hug@xanalys.com] On Behalf Of Bob Hutchison Sent: Thursday, June 24, 2004 6:40 AM To: Rich Hickey Cc: lisp-hug@xanalys.com; Bob Hutchison Subject: Re: Foreign Function Calls to Java On Jun 23, 2004, at 9:50 AM, Rich Hickey wrote: > I am nearing completion of jfli - a fairly extensive interface to Java > from > LispWorks, which I intend to release as open source under the Common > Public > License. > This sounds really good. Sorry, but I have to ask... What do you think the timing is on this? Do I understand what you are saying properly? LW using jfli starts a jvm, can create a bunch of objects, call methods on those objects, implement Java interfaces so can set up lisp handlers for callbacks in a gui say, or a web application, which themselves can call back into Java. What happens across invocations of the LW program -- lisp has an image which can be re-started, Java doesn't? Let me tell you, I'd be happy to have such problems :-) I'm also curious what your intended use is for this... what problem are you trying to solve? Cheers, Bob
On Jun 24, 2004, at 8:16 AM, Rich Hickey wrote: > I hope to have a beta up on SourceForge within a month. This sounds wonderful! Have you considered applying for hosting at common-lisp.net? I'm sure they'd be interested in this project. CL.net is a great place to host CL code and offers more flexible VCS options (CVS, Arch, Darcs, etc). -- Brian Mastenbrook bmastenb@cs.indiana.edu http://cs.indiana.edu/~bmastenb/
On Jun 24, 2004, at 9:16 AM, Rich Hickey wrote: > I hope to have a beta up on SourceForge within a month. Wonderful! > > What I'm trying to do is increase the practicality of Lisp (for me, > personally, I know it's quite powerful on its own), for a wide variety > of > projects. I'm interested in SWT as a portable UI for Lisp (no slight to > CAPI, a very nice library); better integration with the outside world; > access to vast libraries of stuff I'd rather not roll on my own. This is similar to the situation I'm in. For the foreseeable future I can only consider a mixed Java and lisp environment -- my company has a quite large java code base that we cannot ignore. Jfli looks as though we could start using LW where it makes sense. Any thoughts as to how to make lisp programs appear to java? For example, it might be interesting to dress up a lisp program as a servlet, or a bunch of servlets. Or simply to wrap it in a java class. Dave (Fox), what do you and others at Xanalys think of this project? What about some of the lisp projects out there -- some of these would be more than a little interesting to the java community (personally, I'm thinking of Marc Battyani's cl-typesetting and cl-pdf). Cheers, Bob
To the extent LispWorks can create dynamic libraries on the desired platform (I haven't used that feature myself yet) it should be very possible to call Lisp from Java programs, i.e. where the JVM is started outside of jfli/Lisp. One could create a Lisp DLL that implements a native Java method (jfli does this to implement interface proxies). In this method you could (with an as-yet-unwritten-but-trivial function) bind jfli to the JVM that called the method. At that point all of jfli's functionality would become available to the Lisp code. If the method returned an implementation of some sort of factory interface, one could continue to use that from Java to create Lisp-implemented objects. That's just one scenario. If you wanted an out-of-proc connection I guess there's RMI as well as XML-RPC and SOAP. -----Original Message----- From: owner-lisp-hug@xanalys.com [mailto:owner-lisp-hug@xanalys.com] On Behalf Of Bob Hutchison Sent: Friday, June 25, 2004 7:11 AM To: Rich Hickey Cc: <lisp-hug@xanalys.com> Bob Hutchison; davef@xanalys.com Subject: Re: Foreign Function Calls to Java .... Any thoughts as to how to make lisp programs appear to java? For example, it might be interesting to dress up a lisp program as a servlet, or a bunch of servlets. Or simply to wrap it in a java class. ....
On 2004/06/23, Rich Hickey announced the pending release of jfli, a comprehensive Lisp-y interface to the Java Native Interface (JNI). Rich estimated jfli will be in beta in a month. Thanks, Rich! I need to commit to a direction before then, so I wrote a minimal test bed to prove to myself that I can meet my promises even if jfli is delayed for any reason. This testbed is not a substitute for jfli in any manner. I look forward eagerly to jfli's release. If anyone is interested in a "sneak peek" at Java-Lisp integration, you may download the code from: http://199.234.154.207/jni-lisp.html The code is tested in Lispworks for Windows. The Lisp and Java code is portable. The C code, in c2lisp.c, is Windows-specific but should easily be portable. The C code is minimal. Only functions FillVMArgs and Java_Lisp_callVoidPtrJstring are required. FillVMArgs could be replaced with FLI calls from Lispworks. Except for 3 lines of debug code, Java_Lisp_callVoidPtrJstring is a 4-line function enabling callbacks to Lisp from Java. Jeff __________________________________ Do you Yahoo!? New and Improved Yahoo! Mail - Send 10MB messages! http://promotions.yahoo.com/new_mail