users@jersey.java.net

[Jersey] ClientResponse.getStatus() shouldn't return null

From: Gili <cowwoc_at_bbs.darktech.org>
Date: Sun, 18 Jan 2009 20:32:38 -0800 (PST)

As we discussed before, Response.Status is missing quite a few status codes.
As a result, it isn't rare to see ClientResponse.getStatus() return null.
This is problematic because we then end up with the following code:

if (response.getStatus()==null)
  throw new AssertionException("unexpected return code: " +
response.getStatus());
switch(response.getStatus())
{
  case NOT_FOUND:
...
  case NOT_MODIFIED:
...
  default:
    throw new AssertionException("unexpected return code: " +
response.getStatus());
}


1) We have to check for "unexpected return codes" twice.
2) Ideally we want to use enum-style return codes inside switch statements
but we end up having to use integer return codes instead because
Response.Status is missing a lot of important codes.
3) Response.Status.fromStatusCode(int) returns null while
Response.Status.valueOf() throws IllegalArgumentException. This is
inconsistent in my opinion. Why doesn't Response.Status.fromStatusCode(int)
throw IllegalArgumentException as well?

Whatever solution we come up with has to:

1) Provide enums for all HTTP return codes
2) Handle unexpected return codes using a single switch branch
3) Retain backwards compatibility as new HTTP codes are added in the future

What do you guys suggest?

My proposal is:

1) Update JSR311 so all HTTP codes show up in Response.Status, or define a
new ClientStatus that would do the same and have jersey return that instead.
2) ClientStatus.fromStatusCode(int) will need to return some catch-all enum
value (say STATUS_UNKNOWN) on unknown status codes. Developers will be
instructed to never catch this code, instead they should catch "default:".
This will allow us to add new enum values in the future without breaking
backwards compatibility.

This is far from perfect but it's the best I could come up with...

Gili
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