Proxy object issue

gpani · **Posted:** Tue Apr 13, 2004 10:20 am

I am using Hibernate 2.1.2.

The mapping is question is the following:

Code:

<hibernate-mapping>
  <class name="com.foo.bar.beans.user.User" table="USERS" proxy="com.foo.bar.beans.user.User" dynamic-update="false" dynamic-insert="false" mutable="true">
    <id name="userId" column="USERID" type="java.lang.Long" unsaved-value="null">
      <generator class="sequence">
        <param name="sequence">SEQ_USERID</param>
      </generator>
    </id>
    <property name="firstName" type="java.lang.String" update="true" insert="true" column="FIRSTNAME" not-null="true"/>
    ...
    ...
  </class>
</hibernate-mapping>

This is a sample section of code

Code:

  Long userId = new Long(1);
  UserDAO userDAO = new UserDAO();
  User user = userDAO.searchByPrimaryKey(userId);
  logger.debug("Class: " + user.getClass());
  if (user.getClass().isInstance(new User()))
  {
    logger.debug("Result is an instance of the User object.");
  }
  else
  {
    logger.debug("Result is NOT an instance of the User object.");
  }

The following is the output

Code:

Class: com.foo.bar.beans.user.User$$EnhancerByCGLIB$$f0dddb0d
Result is NOT an instance of the User object.

I am guessing that this is a result of Proxy setting. Does anyone know how I can get the result to be an instance of my User object. I have tried to typecast it but it makes no difference.

Any suggestions?

baliukas · **Posted:** Tue Apr 13, 2004 12:00 pm

Quote:

I am guessing that this is a result of Proxy setting. Does anyone know how I can get the result to be an instance of my User object. I have tried to typecast it but it makes no difference.

Why do you think result is not an instance of your User class ? User class is a superclass for com.foo.bar.beans.user.User$$EnhancerByCGLIB$$f0dddb0d , so result is an instance of User class, but User instance is not an instace of result class. Is it a problem ?

gpani · **Posted:** Tue Apr 13, 2004 12:09 pm

Quote:

Why do you think result is not an instance of your User class ? User class is a superclass for ?

The problem is that when I pass the User object into a separate method and do the following

Code:

object.getClass().isInstance(new User())

it returns a false. Consequently, I can't process further in my code. I do similar processing in other parts of my code and it works fine. The User object is the only one that is proxy loaded.

baliukas · **Posted:** Tue Apr 13, 2004 12:23 pm

Yes, proxy is a subclass.
"User.class.isInstance(myObject)" must return true.
"if(myObject instanceof User)" is a right way too.

max · **Posted:** Tue Apr 13, 2004 1:51 pm

or if you want a dynamic instanceof then use isAssignableFrom instead

gpani · **Posted:** Tue Apr 13, 2004 3:41 pm

Both isAssignableFrom and instanceof worked. Thank you very much. I am still surprised that isInstance doesn't work.

baliukas · **Posted:** Tue Apr 13, 2004 4:26 pm

gpani wrote:

Both isAssignableFrom and instanceof worked. Thank you very much. I am still surprised that isInstance doesn't work.

JAVA compiler implements "instanceof" as "isInstance", but "isInstance" and
"isAssignableFrom" sometimes confuses, it is more clear to use "instanceof" operator.