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   More information at http://www.thekode.net/ruby/rjni

                    rjni: Java binding for Ruby through JNI

   Copyright (c) 2003 Mauricio Julio Fern?ndez Pradier
   <batsmanDOTgeoATyahooDOTcom>

   WARNING: This is a technology preview. The software is not even alpha
   quality at the moment and is not meant to be used yet. It is only
   provided to present the techniques employed and (hopefully) to
   accelerate the development.

   Feedback: please don't hesitate to contact me to criticize, suggest new
   features or help with the development :)

License

   For the time being, the same as Ruby. Might switch to LGPL in the future.

Status

     * The APIs are quickly stabilizing.
     * The base layer still needs some work and further testing.
     * Several low-level issues remain to be solved.
     * The higher-level APIs have yet to be documented and tested rigorously.

What is rjni?

   rjni exposes the Java Native Interface to Ruby. This allows the programmer
   to instantiate Java objects, manipulate them, define Java classes, etc..
   from Ruby.

   Note that rjni is not meant to embed Ruby into Java, although it can be
   used to ease integration in that case.

Building

   This technology preview is meant to illustrate the possibilities offered
   by rjni. It is by no means a usable library yet. The build process is
   quite tricky, as it involves linking against the Java libraries and is
   therefore highly system-dependent.

   The steps are:
    1. creating the Makefile. This is done by executing

  ruby extconf.rb \
     --with-jsdk-include=/usr/local/java/j2sdk1.4.1/include/ \
     --with-jsdk-lib=/usr/local/java/j2sdk1.4.1/jre/lib/i386/ \
         --with-jsdk-so-include=/usr/local/java/j2sdk1.4.1/include/linux/

       You have to replace the paths above by the appropriate values for your
       local Java installation. Note that rjni has been tested with Blackdown
       1.4.1, and, although it should be possible to build it with other
       JSDKs, compilation and/or linking might fail unless you get the above
       options right and/or modify extconf.rb itself (or end up modifying the
       Makefile by hand :)
    2. Compiling

    make
   

    3. You can now run the tests:

   
    ./tc_all.sh

       You will notice a short pause after the execution of the script. This
       is normal and expected at the moment.
    4. High-level API demo:

   
    ./test_reflect.sh

Problems

  Compilation

       Were you to experience difficulties when compiling, you'd have to make
       sure that the appropriate -rpath and/or -L options are passed to gcc.

  Execution

       Sometimes ld.so will be unable to resolve symbols at runtime; you will
       then need to set the LD_LIBRARY_PATH environment variable
       to some sensible value.

APIs

       RJNI will have at least 3 APIs:
          * RJNI: a low-level straight-forward mapping of the Java Native
            Interface to Ruby. All operations on Java objects and classes are
            ultimately performed through this layer.
          * RJNI::Java: a direct conversion of java.lang.reflect and
            associated classes to Ruby. It is built upon RJNI.
          * RJNI::Reflect: magic reflection of Java objects to Ruby, such
            that they can seemingly be manipulated exactly like Ruby objects.
            This involves automatic method dispatching, singleton class
            abstraction (static methods become singleton methods of the class
            object), some automatic type conversions, attribute setters and
            getters, etc.

-- 
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	Running Debian GNU/Linux Sid (unstable)
batsman dot geo at yahoo dot com

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