Hello Robert,
On 07/01/25 12:05 am, robert engels wrote:
> ...
>
> 2. Another proposed change to Headers would be to add a protected
constructor that allowed you to pass in the Map implementation (or
null), allowing specialized map data structures that are better suited
to http headers storage, especially when being converted to/from http2
headers.
>
> Although it is possible to subclass Headers to provide your own map,
you still pay a penalty because the base class will instantiate a map,
and the code is quite ugly as you must override every method in the
Headers class. You can see a sample implementation here
https://github.com/robaho/httpserver/blob/main/src/main/java/robaho/net/httpserver/OptimizedHeaders.java
>
> The subclass does offer the ability to bypass the normalization
completely with a package level method to be used internally by the
server when it has already guaranteed the key is normalized.
I don't know if you have noticed, but starting Java 18, the Headers
class already provides a (public) constructor which allows a Map to be
passed in to the constructor
https://docs.oracle.com/en/java/javase/23/docs/api/jdk.httpserver/com/sun/net/httpserver/Headers.html#%3Cinit%3E(java.util.Map).
The implementation of the constructor however copies over the key/values
into an internal Map of its own, so the passed Map (implementation)
plays no further role after that point.
In my opinion, in its current form, the Headers class provides enough
flexibility to allow for a subclass of Headers to provide a more
efficient implementation if it wants to. Like you note, such a subclass
needs to implement all the methods of java.util.Map interface to be able
to properly provide that support, but it's still doable.
>
> 3. The public static of() methods in Headers should be
changed/removed, as they create a dependency on a sun internal class
(sun.net.httpserver.UnmodifiableHeaders) from a public “api” class.
These could be changed to instead wrap the map with an unmodifiable map.
>
com.sun.net.httpserver.Headers is an API class and the method signature
of com.sun.net.httpserver.Headers.of() is:
public static com.sun.net.httpserver.Headers of(Map<String,List<String>>
headers)
The implementation of that method currently returns an instance of
sun.net.httpserver.UnmodifiableHeaders which is an internal
implementation class belonging to the same module. I don't follow why
that's a bad thing - the API itself, through the method signature,
doesn't expose any internal implementation class.
-Jaikiran
