[Dltk-dev] Calling Java from Ruby

[Andrew Mickish <mickish@xxxxxxx>]

How can I call static Java methods located in a different project than 
my Ruby script?

I have a Java project named ZooGlue containing the class 
zoo.util.Truthiness, and a Ruby project named Zuby containing the script 
TestTruthiness.rb starting with these lines:

   include Java
   include_class Java::zoo.utils.Truthiness

When I run TestTruthiness.rb, I get
   
C:/downloads/Ruby/jruby-1.1.4/lib/ruby/site_ruby/1.8/builtin/javasupport.rb:49:
   in `method_missing': cannot load Java class zoo.utils.Truthiness 
(NameError)
   from C:\Workspace\Zuby\TestTruthiness.rb:9

I probably ought to put ZooGlue on Zuby's build path somehow, but the 
Build Path dialog box for the Ruby project does not list any of my Java 
projects as eligible to add to the build path.  Should I explicitly 
refer to  C:\Workspace\ZooGlue\bin\zoo\utils\Truthiness.class in the 
Ruby script somehow?

I am using Eclipse 3.4, DLTK 9.5, and my Ruby Interpreter executable is 
C:\downloads\Ruby\jruby-1.1.4\bin\jruby.bat

######################################################################
# Project: Zuby
# File: TestTruthiness.rb

include Java
include_class Java::zoo.utils.Truthiness

def show(it)
 println "" + it + ":\t" + isTrue(it) + "\t" + isFalse(it);
 println "\t" + (it ? "true":"false") + "\t" + ((!it)?"true":"false")
end

0 ? "TRUE" : "FALSE"

show( true )
show( false )
show( 0 )
show( 1 )
show( null )
show( "bye" )
show( "" )
show( 'x' )

######################################################################

//////////////////////////////////////////////////////////////////////
// Project: ZooGlue
// File: Truthiness.java

package zoo.utils;

/**
* Everything is true except false and null.
*/
public class Truthiness {
  
   static public boolean isFalse (Object o)
   {
       return o == null || Boolean.FALSE.equals(o);
   }

   static public boolean isTrue (Object o)
   {
       return isFalse(o) == false;
   }
}

//////////////////////////////////////////////////////////////////////