[jboss-as7-dev] Attribute meta-data: max-length

[Brian Stansberry]

To provide some context:

In subsystems coded using current best practices, the definition of a 
string attribute is created using a SimpleAttributeDefinition.

static final SimpleAttributeDefinition FOO = new 
SimpleAttributeDefinitionBuilder("foo", ModelType.STRING).build();

By default, that attribute will be constrained to having a min-length of 
1 and a max-length of Integer.MAX_LENGTH.

Support for null/undefined is separate:

static final SimpleAttributeDefinition FOO = new 
SimpleAttributeDefinitionBuilder("foo", ModelType.STRING)
   .setAllowNull(true)
   .build();

You can also constrain the max-length of the string by passing in a 
custom validator to override the default:

static final SimpleAttributeDefinition FOO = new 
SimpleAttributeDefinitionBuilder("foo", ModelType.STRING)
   .setAllowNull(true)
   .setValidator(new StringLengthValidator(1, 10))
   .build();

With Heiko's proposal, if you didn't specify a StringLengthValidator or 
the one you specify didn't pass a max-length param to the constructor, 
the default would change from Integer.MAX_LENGTH to something smaller 
(e.g. 245, 1024). If you needed something larger you'd need to modify 
your subsystem to declare it.

On 1/22/13 9:56 AM, Heiko Braun wrote:
>
> We have the case within the UI that the client needs to distinguish text input types. I most cases a simple text inout is sufficient, but in some cases a text area is more appropriate (i.e. datasource>new connection sql).  I am wondering, if the max-length attribute could be used for it.
> It's currently tight to ModelType.STRING, which is fine.
>
> In order to show the expected results, we would need to decrease the default value for max-length, to something smaller (245, 1024). This way we could provide text input for for anything below that size and text area for anything else.
>
> Some implications I would like to hear your thoughts about:
>
> a) lowering the default max-length might break your subsystem and/or specific clients
> b) keeping the current default and doing it case-by-case will result in text input (opposed to text area) for all String attributes once we switch to a dynamic UI (usability drawback).
>
>
> Regards, Heiko
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-- 
Brian Stansberry
Principal Software Engineer
JBoss by Red Hat