JavaのInterfaceをJRubyのクラスに実装してJavaから呼びだす

GUIはJava、処理はRubyで書きたくて、RubyとJavaのクラスを相互に扱う必要があったのでメモ

$ tree
.
├── out
│   └── production
│       └── JRubyTest
│           └── JrubyTest
│               ├── Main.class
│               └── TestInterface.class
├── ruby
│   ├── TestInterface.jar
│   └── test_class.rb
└── src
    └── JrubyTest
        ├── Main.java
        └── TestInterface.java

TestInterface.java

package JrubyTest;

public interface TestInterface {
    java.lang.String hello();
}

TestClass.rb

java_import 'JrubyTest.TestInterface'

class TestClass
  include TestInterface
  def initialize name
    @name = name
  end

  def hello
    "hello #{@name}"
  end
end

Main.java

package JrubyTest;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptContext;
import javax.script.ScriptException;

public class Main {
    public static void main(String[] args) {
        ScriptEngineManager m = new ScriptEngineManager();
        ScriptEngine rubyEngine = m.getEngineByName("jruby");
        ScriptContext context = rubyEngine.getContext();
        try {
            File file = new File("ruby/test_class.rb");
            try {
                FileReader reader = new FileReader(file);
                rubyEngine.eval(reader);
                String name = "'Taro'";
                Object testClass = rubyEngine.eval("TestClass.new " + name, context);
                if (testClass instanceof TestInterface){
                    TestInterface test = (TestInterface) testClass;
                    System.out.println(test.hello());
                }
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }

        } catch (ScriptException e) {
            e.printStackTrace();
        }
    }
}