RFR: 8252304: Seed an HttpRequest.Builder from an existing HttpRequest

[Daniel Fuchs]

On Wed, 4 Nov 2020 15:18:01 GMT, Chris Hegarty <chegar at openjdk.org> wrote:

>> Hi,
>> 
>> Could someone please review our code for JDK-8252304: 'Seed an HttpRequest.Builder from an existing HttpRequest'?
>> 
>> This RFR proposes a new factory method for creating a new `HttpRequest` builder from an existing `HttpRequest`.
>> This method can be used to build a new request equivalent to the given request, but with different attributes. For instance, it will allow the user to take an existing request and add or change a particular header, provide a new `URI`, etc.
>> 
>> 
>> Kind regards,
>> Patrick & Chris
>
> src/java.net.http/share/classes/java/net/http/HttpRequest.java line 344:
> 
>> 342:             throw ex;
>> 343:         } catch (RuntimeException r) {
>> 344:             throw new IllegalArgumentException("Illegal request parameters", r);
> 
> I'm a little concerned about this. It seems unnecessary, and adds complexity to an otherwise straightforward piece of code. Any accessor of the given request that throws should probably just be allowed to flow out. If needed, we could even mention that in the specification.

The current code side step the issue of having to explain in the spec that any kind of `RuntimeException` could be propagated upwards. With this, calling code can just try catch `IAE`. It's a little more user-friendly.

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PR: https://git.openjdk.java.net/jdk/pull/1059