Hibernate + Middlegen + generating code

dmitry · **Joined:** Thu Dec 15, 2005 3:03 pm **Posts:** 5

I use Hibernate and Middlegen for working with Oralce database. Middlegen generated java classes successfully. But I want to add some new methods and attributes to it. Can I specified that modification and apply it every time when I regenerate classes?
For example: it generates class A:

Code:

public class A {
  private BigDecimal xmlFile;
  public A() {};
  // ...
}

and i want to generate class as

Code:

public class A { 
  private BigDecimal xmlFile;
  // new property that is not mapped on the database. 
  int new_prop;
  public A() {
    // read data from file and specify new_prop. 
    new_prop = 2; 
  }
  // ....
}

kochcp · **Posted:** Thu Dec 15, 2005 3:39 pm

what you can do is the following. Have middlegen generate a base class and then write another class extending that base class and adding that extra bit of business logic. This way, if the db changes, you run middlegen and the whole class changes w/o having to write anything.

Code:

<class
    name="package.ClassA" 
    table="table_a"
    
>
    <meta attribute="generated-class" inherit="false">package.BaseClassA</meta>

this will generate a POJO named BaseClassA. Then, you write another class named ClassA which extends BaseClassA and adds that little bit of business logic you need. By declaring it this way you still call this in hibernate/hql using the orig. class name of ClassA.

dmitry · **Joined:** Thu Dec 15, 2005 3:03 pm **Posts:** 5

It seems great. Thanks. I'll test it now.

dmitry · **Joined:** Thu Dec 15, 2005 3:03 pm **Posts:** 5

I have added "meta" tag to the BaseClassA.hbm.xml.

But when i write in a code:

Code:

List list = session.createQuery("from table_a").list();
ClassA cl = (ClassA) list.get(0);

I have a java.lang.ClassCastException:
And

Code:

BaseClassA cl = (BaseClassA) list.get(0);

works correctly

kochcp · **Posted:** Fri Dec 16, 2005 10:16 am

Are you sure you declared it correctly? I think it'd be better if the mapping file was named ClassA.hbm.xml instead of BaseClassA.hbm.xml.

also, HQL runs off class names.

change that query to "from ClassA"