Rjb (Ruby Java Bridge) loader with before_load and after_load hooks
When working with multiple gems or several rails initializer files that use Rjb, you need to make sure that all java dependencies are set up before running Rjb::load. This is necessary because Rjb can only be loaded once.
As an example, you could use rjb-loader to change classpath and java options. You can do this by adding a 'before_load' hook to your gem or rails initializer.
The 'after_load' hook, on the other hand, should be used when your code needs to run after Rjb::load. For instance, when you need to use java classes.
gem install rjb-loader
Add rjb-loader to your Gemfile:
gem "rjb-loader"For any issues related to the java/ruby integration, please check out: http://rjb.rubyforge.org/. You will find here plenty tips that might help you to solve your problem.
Example from jasper-rails:
...
RjbLoader.before_load do |config|
# This code changes the JVM classpath, so it has to run BEFORE loading Rjb.
Dir["#{File.dirname(__FILE__)}/java/*.jar"].each do |path|
config.classpath << File::PATH_SEPARATOR + File.expand_path(path)
end
# We can also change java options here, if we want to.
config.java_options += ['-Xms256M', '-Xmx512M']
end
RjbLoader.after_load do |config|
# This code needs java classes, so it has to run AFTER loading Rjb.
_Locale = Rjb::import 'java.util.Locale'
JasperRails.config[:report_params]["REPORT_LOCALE"] = _Locale.new('en', 'US')
end
...Copyright (C) 2013 Marlus Saraiva
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