hbm2java equals generation

basca · **Posted:** Tue Jan 10, 2006 12:47 pm

Hibernate version: 3.1-beta

Dear list,

When I trigger generation of the equals method in my mappings like this:

Code:

      <id name="id" type="java.lang.Long">
         <meta attribute="use-in-equals">true</meta>
         <generator class="native" />
      </id>

then hbm2java produces the following code:

Code:

   public boolean equals(Object other) {
                 if ( (this == other ) ) return true;
       if ( (other == null ) ) return false;
       if ( !(other instanceof BaseRelatie) ) return false;
       BaseRelatie castOther = ( BaseRelatie ) other; 
         
       return ( (this.getId()==castOther.getId()) || 
                           ( this.getId()!=null && castOther.getId()!=null
                             && this.getId().equals(castOther.getId()) ) );
   }

The

Code:

(this.getId()==castOther.getId()) ||

fragment implies that 2 instances are equal when both ids are null. So when I add 2 (not yet persisted) instances to a Collection, this fragment will cause the first instance to be overwritten by the second. Therefore this fragment should be removed IMO.

Kind regards,
Bas

max · **Posted:** Tue Jan 10, 2006 1:46 pm

eh - then don't use id in equals! (see hibernate.org about equals and hashcode)