dbradbury-20100406-0.txt

Blog Title:  JRuby Helps Us Craft Quality Software
Author:      Doug Bradbury
Date:        April 6th, 2010

dbradbury-20100406-1.java

//The Java Interface
public interface ConfigurationStore
{
 void put(Map<string> pairs);
 void put(String key, String value);
 String get(String name);
}

dbradbury-20100406-2.rb

#The Ruby Implementation
class ConfigurationStore
 include Java::package.ConfigurationStore
  def get(key)
  .....
  end
# Notice how we were able to implement the function 
# overloading present in the interface by
# using a variable arguments in one ruby method.
 def put(*args)
  if args.size == 2
   ....
  elsif args.size == 1
   .....
  else
   raise ArgumentError.new("put() takes a Hash
                (or a Java Map) or a key and value pair")
  end
 end
end

dbradbury-20100406-3.java

// instantiating a Ruby object in Java
RubyInstanceConfig config = new RubyInstanceConfig();
Ruby runtime = JavaEmbedUtils.initialize(new ArrayList(), config);
RubyRuntimeAdapter evaler = JavaEmbedUtils.newRuntimeAdapter();
IRubyObject result = evaler.eval(runtime, "require 'configuration_store';" +
                                "config_store = ConfigurationStore.new"); 
store = (ConfigurationStore) result.toJava(ConfigurationStore.class);