Guice should never ever inject a null value about guice

[gissuebot]

From limpbizkit on February 27, 2007 21:28:01

I imagine there are scenarios where null is reasonable. Suppose you have a service that checks permissions
against a Guice-provided user. No user might imply non-interactive use, such as by a batch process:

public class AccountService {
  @Inject User user;
  @Inject Customer customer;
  public Account getAccount() {
    Account account = lookupCustomerAccount(customer.getId());
    if(user != null && !account.isViewableBy(user)) {
      throw new InsufficientPermissionsException();
    }
    return account;
  }
}

IMHO, this particular situation doesn't really lend itself to a null-object pattern.

But I do think injecting null is something you'd want to do very rarely. So perhaps instead of banning it
outright, we should make it on-by-default and users could opt-out (like required=false):
  @Inject(nullable=true) User user;

[gissuebot]

From kevinb9n on February 28, 2007 11:17:34

I don't see why a null-object pattern wouldn't work here.  But actually in this case
you don't really want a User at all, you want a ThingThatDecidesPermissions or
PermissionProfile or Authorizations or some such object, and that should never be null.

Null is stinky...

[gissuebot]

From crazyboblee on February 28, 2007 12:24:17

Or an anonymous/guest user. Down with null.

[gissuebot]

From crazyboblee on February 28, 2007 14:45:08

(No comment was entered for this change.)

Labels: 1.0RC3

[gissuebot]

From kevinb9n on March 01, 2007 02:58:35

Fixed with revision 248 .

Status: Fixed