ManyToMany association and and join table

ainz · **Joined:** Fri Jan 12, 2007 10:41 am **Posts:** 4

Hello

I have an issue that I hope someone may be able to shed some light on.

I have a problem modelling the security concepts of principals and roles with a many-to-many association.

I am using Hibernate Core & Hibernate Annotations 3.2.1.GA on MySQL 5.0.

My entities are as follows:

Code:

@Entity()
@Table()
public class Authority {
   ...
   
   @Column(unique = true, nullable = false)
   private String name;

   ...
}

@Entity()
@Table()
public class Principal {
   ...
   
   @Column(unique = true, nullable = false)
   private String identity;

   private String password;

   @ManyToMany(
      cascade = {CascadeType.PERSIST, CascadeType.MERGE}, 
      fetch=FetchType.EAGER, 
      targetEntity=Authority.class
   )
   private Set<Authority> authorities;
   
   ...
}

I create authorities first, then create principals later. When I create a principal, I find the exisiting authority I want to assign to the principal using a query, then add it to his authorities set.

But the join table, principal_authorities, remains empty.

I believe I am missing something simple here, but I just can't see it.

Thanks in advance.

emmanuel · **Posted:** Fri Jan 12, 2007 8:22 pm

you need to show your code

ainz · **Joined:** Fri Jan 12, 2007 10:41 am **Posts:** 4

Thanks for the response.
Okay, more of the code follows, which builds on the classes above.

The class that manages Principals is as follows:

Code:

public class PrincipalManager {

   private PrincipalDao principalDao;
   private AuthorityDao authorityDao;
   
   public Principal createPrincipal(String accountIdentifier, String password, String[] authorityNames) {
      Principal principal = constructPrincipal(accountIdentifier, password, authorityNames);
      principalDao.create(principal);
      return principal;
   }

   private Principal constructPrincipal(String accountIdentifier, String password, String[] authorityNames) {
      Principal principal = new Principal(accountIdentifier, password);
      if (authorityNames.length > 0) {
         for (String authName : authorityNames) {
            List<Authority> matchingAuthorities = authorityDao.findByName(authName);
            Authority matchingAuthority = (matchingAuthorities.size() > 0) ? matchingAuthorities.get(0) : null;
            if (null != matchingAuthority) {
               principal.addAuthority(matchingAuthority);
            } 
         }
      }
      return principal;
   }

   public Set<Authority> addAuthorities(String[] authorityNames) {
      Set<Authority> createdAuthorities = new HashSet<Authority>();
      for (String authname : authorityNames) {
         createdAuthorities.add(addAuthority(authname));
      }
      return createdAuthorities;
   }
   
   public Authority addAuthority(String name) {
      Authority dba = new Authority(ROLE_PREFIX + name.toUpperCase());
      authorityDao.create(dba);
      return dba;
   }
}

The code snippet used to create the authorities and the principal is as follows:

Code:

// create set of available roles
String[] authorities = { "SITE.USER", "SITE.ADMIN" };
principalManager.addAuthorities(authorities);

// create principal with a single role assigned
String[] authoritiestToGrant = { "SITE.USER" };
Principal principal = principalManager.createPrincipal("someone@somewhere.com", "pass1234", authoritiestToGrant);

And the code snippet used to create entities (within each DAO class) is as follows:

Code:

boolean allowCreate = true;
SessionFactoryUtils.getSession(sessionFactory, allowCreate).save(object);

I think the problem is somehow related to the fact that each Principal contains a set of authorities, but I create the 'master list' of authorities before creating the principal.

As you can see when the Principal is constructed, I search for a matching role and assign it to the Principal.

After this code has executed, the join table principal_authorities remains empty.

ainz · **Joined:** Fri Jan 12, 2007 10:41 am **Posts:** 4

The addAuthority method on Principal is simple and looks like this:

Code:

   
public void addAuthority(Authority authority) {
   this.authorities.add(authority);
}

ainz · **Joined:** Fri Jan 12, 2007 10:41 am **Posts:** 4

This was down to transaction management error: case closed.