Grails Domain modification on save

Say I have a user domain class with fields username and password. For simplicity say I would like to store the passwords as a SHA-512 hash. I also want to validate the password prior to hashing it, but also transparently hash the password before saving it. Is there a way to do this in the domain object?

static constraints = 
{
    username(blank: false, unique: true);
    password(minSize: 10);
}

Instead of saying:

def user = new User(username: "joe", password: createHash("joepass"));

where I can't validate the hash

def user = new User(username: "joe", password: "joepass");
if(user.validate())
{
    user.save(); // Would then turn password into a hash on save
}
else
{
    // Handle validation errors
}

Following GORM Ev开发者_高级运维ents I've come up with the following:

def beforeInsert = { doHash(); }
def beforeUpdate = { doHash(); }
void doHash()
{
    if(this.password.size() != 32)
    {
        this.password = this.password.encodeAsHash(); // I wrote a codec for this
    }
}

Now this works fine when creating new users. However, if I create a user, give them a password, and save them, then change the password and re-save neither of these methods gets called and the plain test password gets stored.

---

Use the GORM Events

On the save or update events you can do the create hash

   def beforeInsert = {
       // do hash magic
   }
   def beforeUpdate = {
        // do hash magic
   }