ruby block interface for anonymous class

java_example.java

// ex. Java invocation
public void save() {
   txTemplate.execute(new TxCallback() {
      public Object execute(TransactionHolder tx) throws Exception {
         //do stuff
         return something;
      }
   });
}

ruby_example.rb

# ex. ruby invocation
Transaction.execute { something }

transaction.rb

class Transaction
  class CallbackWrapper
    include Java::org.aps.eop.hibernate.springtx.TxCallback
       
    def initialize(&blk)
      @blk = blk
    end
       
    def execute(tx) 
      @blk.call
    end
  end
    
  def self.execute(&blk)
    txTemplate = SpringAppContext.get_bean(bean_name)    
    txTemplate.execute(CallbackWrapper.new(&blk))
  end
end

TxCallback.java

public interface TxCallback {
    public Object execute(TransactionHolder txHolder) throws Exception;
}

TxTemplate.java

public class TxTemplate {
   ....

   public Object execute(TxCallback callback) throws Exception {

       return callback.execute(txUtil.getTransaction());
   }
   ....
}