Hibernate validations on save (insert) only

Question

We encountered a problem with legacy code. There is a validation set for a "username" field, validating its length and making sure it contains at least one letter: ``` @Column(name = "username") @Size(min = 4, max = 40) @Pattern(regexp = "^.*[a-zA-Z]+.*$") private String username; ``` The problem we have is that some existing legacy data do not fit these validations, and I'm trying to find a way to make these validations to be ignored for legacy data (old users), while still be applied to newly created users. I was thinking about moving the validations to `setUsername(...)` method (so value will be validated on an actual change only), but this caused an exception: ``` javax.validation.ValidationException: Annotated methods must follow the JavaBeans naming convention. setUsername() does not. ``` I also made sure the entity is set to `dynamicUpdate=true`, but this doesn't help since hibernate is validating all properties, even if no change occurred. How can I prevent these validations t…

Accepted Answer

After two days of research I found out how to make this work. Apparently, specifying validations that would be validated on `INSERT` only is not that difficult. The only changes required are to set these validations to a specific validation group and to validate this group during `INSERT`/`pre-persist` events.

First of all I created an interface called `platform.persistence.InsertOnlyValidations` to be used as a group which will be validated during pre-persist only.

Than, I added the group to the `username` field validations:

```
@Column(name = "username")
@Size(min = 4, max = 40, groups = {InsertOnlyValidations.class})
@Pattern(regexp = "^.*[a-zA-Z]+.*$", groups = {InsertOnlyValidations.class})
private String username;
```

This instructs hibernate not to use these validations as part of the default group. Now, I needed to instruct hibernate to validate these validation rules during insert only. The way to do that is very simple, I needed to pass the property `javax.persistence.validation.group.pre-persist`, while indicating which groups will be validated during a `pre-persist` event:

```
javax.persistence.validation.group.pre-persist=javax.validation.groups.Default,platform.persistence.InsertOnlyValidations
```

This instructs hibernate that during a `pre-persist` event all default validations will be validated (`javax.validation.groups.Default`) in addition to all the validations included in the `InsertOnlyValidations` group.

Hibernate validations on save (insert) only

Solution

Problem