Encapsulate attributes for ExtensionContext

[jlink]

Encapsulate attributes for Test|ContainerExtensionContext:

• do not expose map
• delegate attribute retrieval to parent

[jlink]

Implemented encapsulating methods in cf91ce4

[jlink]

Alternative suggestion

Extend ExtensionContext with

interface ExtensionContext {
  Object get(Object key);
  void store(Object key, Object value, Visibility visibility);
  default   void store(Object key, Object value) {
    store(key, value, Visibility.DEFAULT);
  }
}

and

enum Visibility {
  DEFAULT, //visible only in this extension but inherited from ancestor extension contexts
  EXTENSION, //visible only in this extension but in the full tree of extension contexts
  LOCAL, //only visible in this extension and this extension context
  GLOBAL //visible in all extensions and in the full tree of extension contexts
}

This would then replace ContextScope and get|setAttribute.

[jlink]

Team decision for the time being:
Implement the following:

 interface ExtensionContext...

    default Object get(Object key) {
        return get(key, "");
    }

    Object get(Object key, String namespace);

    default void put(Object key, Object value) {
        put(key, value, "");
    }

    void put(Object key, Object value, String namespace);

    Object getOrComputeIfAbsent(Object key, Function<Object, Object> defaultProvider, String namespace) {
        Object value = get(key);
        if (value == null) {
            value = defaultProvider.apply(key);
            put(key, value, visibility);
        }
        return value;
    }

    default Object getOrComputeIfAbsent(Object key, Function<Object, Object> defaultProvider) {
        return getOrComputeIfAbsent(key, defaultProvider, "");
    }

Choose a suitable value for default namespace, e.g. have an object internally but only allow Strings from outside.

[jlink]

I'm working on it.

[jlink]

I suggest other changes in addition to the ones above:

• extract put/get/etc into an interface Store
• make the store available via ExtensionContext.getStore()
• Alternative 1: Remove overloaded methods and provide ExtensionContext.getStore(String namespace)
• Alternative 2: Make store available as a separate parameter in all extension points to communicate clearly: That's the way to persist state
• Encapsulate namespace in a Namespace value object with static utility methods like Namespace.DEFAULT, Namespace.localFor(anObject1, anObject2), Namespace.forClass() etc.

Feedback?

[jlink]

What I'm planning to do is implement it in master but leave the old attributes in place. Thus you can all see how it looks but no existing functionality must be touched.

Any objections?

[bechte]

For any new features, for which we do not yet know in which direction we should go, I would strongly recommend not to work in master. That's exactly what I am doing with the discovery mechanism.

[jlink]

Ok. I'll only do in master on what we agreed yesterday.

Am 16.01.2016 um 12:36 schrieb Stefan Bechtold notifications@github.com:

For anything new features, for which we do not yet know in which direction we should go, I would strongly recommend not to work in master. That's exactly what I am doing with the discovery mechanism.

—
Reply to this email directly or view it on GitHub.

[jlink]

Agreed changes are done in master. Suggestions from above must still be discussed.

[jlink]

Implemented suggestion in https://github.com/junit-team/junit5/tree/issue82-store for review

[jlink]

Merged suggestion after team decision in #128.

Missing:

• Remove all usages of ExtensionContext.put/get/removeAttribute
• Remove implementation of ExtensionContext.put/get/removeAttribute

[jlink]

Resolved in e103a16