From: SAKURAI Masashi <m.sakurai@...>
Date: 2005-06-22T07:38:50+09:00
Subject: Re: Ruby and Java

Hi,

> I have a vendor product with Java APIs that I need to write against
> and would like to use Ruby.
> 
> Does anyone have an opinion on the most reliable way to interact with
> Java from Ruby?  I've seen some different projects, but can't tell if
> there is any major difference between how they are implemented or
> which are actively maintained.

I have another implementation Java-Ruby bridge that is written in pure
Java and Ruby. 

YAJB
http://www.cmt.phys.kyushu-u.ac.jp/~M.Sakurai/cgi-bin/fw/wiki.cgi?page=YAJB

This bridge is implemented by Javassist and xmlrpc communication.
Javassist is bytecode engineering tool. I used xmlrpc to connect java
and ruby.  Although the communication is very slow, the bridge can
establish connection on the many environment.

The YAJB is designed for achievement of following goals:

* easy to use (at least for me, on cygwin/windows XP)
* allowing simple and complete GUI code as we write in Java
* writing implementation of Java interfaces and any class in Ruby.

I wrote the code for my own purpose, analyzing numerical data and 
visualizing it with my plot library, not general use.
So I'm sorry if you meet troubles. (I'm not sure using gem or setup.rb...)


Here is the sample YAJB code, handling modal JDialog:

=============================

#!/usr/bin/ruby

require 'yajb/jbridge'
include JavaBridge

jimport "java.awt.*"
jimport "java.awt.event.*"
jimport "javax.swing.*"

label = jnew :JLabel, "Hello World!"

button = jnew :JButton, "open!"
action = jextend :ActionListener
button.addActionListener(action)

panel = jnew :JPanel, jnew(:GridLayout,2,1)
panel.add(label)
panel.add(button)

frame = jnew :JFrame, "JDialog DEMO"
frame.getContentPane.add(panel)
frame.pack

class << action
  def init(f,l)
	@frame = f
	@label = l
  end

  def actionPerformed(event)
	dlg = jnew :JDialog, @frame, "Modal Dialog!", true

	text = jnew :JTextField,12

	okbtn = jnew :JButton,"OK"
	action = jextend :ActionListener
	class << action
	  def init(d,t,l)
		@dlg = d; @text = t; @label = l
	  end
	  def actionPerformed(e)
		@label.setText(@text.getText())
		@dlg.dispose()
	  end
	end
	action.init(dlg,text,@label)
	okbtn.addActionListener(action)

	panel = jnew :JPanel
	panel.add(text)
	panel.add(okbtn)

	dlg.getContentPane.add(panel)
	dlg.pack
	dlg.show
  end
end

action.init(frame,label)

wc = jextend :WindowAdapter
class << wc
  def windowClosing(e)
	break_bridge
	wakeup_thread
  end
end
frame.addWindowListener(wc)
frame.show()

stop_thread

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