SPARK-1093: Annotate developer and experimental API's

This patch marks some existing classes as private[spark] and adds two types of API annotations:
- `EXPERIMENTAL API` = experimental user-facing module
- `DEVELOPER API - UNSTABLE` = developer-facing API that might change

There is some discussion of the different mechanisms for doing this here:
https://issues.apache.org/jira/browse/SPARK-1081

I was pretty aggressive with marking things private. Keep in mind that if we want to open something up in the future we can, but we can never reduce visibility.

A few notes here:
- In the past we've been inconsistent with the visiblity of the X-RDD classes. This patch marks them private whenever there is an existing function in RDD that can directly creat them (e.g. CoalescedRDD and rdd.coalesce()). One trade-off here is users can't subclass them.
- Noted that compression and serialization formats don't have to be wire compatible across versions.
- Compression codecs and serialization formats are semi-private as users typically don't instantiate them directly.
- Metrics sources are made private - user only interacts with them through Spark's reflection

Author: Patrick Wendell <pwendell@gmail.com>
Author: Andrew Or <andrewor14@gmail.com>

Closes #274 from pwendell/private-apis and squashes the following commits:

44179e4 [Patrick Wendell] Merge remote-tracking branch 'apache-github/master' into private-apis
042c803 [Patrick Wendell] spark.annotations -> spark.annotation
bfe7b52 [Patrick Wendell] Adding experimental for approximate counts
8d0c873 [Patrick Wendell] Warning in SparkEnv
99b223a [Patrick Wendell] Cleaning up annotations
e849f64 [Patrick Wendell] Merge pull request #2 from andrewor14/annotations
982a473 [Andrew Or] Generalize jQuery matching for non Spark-core API docs
a01c076 [Patrick Wendell] Merge pull request #1 from andrewor14/annotations
c1bcb41 [Andrew Or] DeveloperAPI -> DeveloperApi
0d48908 [Andrew Or] Comments and new lines (minor)
f3954e0 [Andrew Or] Add identifier tags in comments to work around scaladocs bug
99192ef [Andrew Or] Dynamically add badges based on annotations
824011b [Andrew Or] Add support for injecting arbitrary JavaScript to API docs
037755c [Patrick Wendell] Some changes after working with andrew or
f7d124f [Patrick Wendell] Small fixes
c318b24 [Patrick Wendell] Use CSS styles
e4c76b9 [Patrick Wendell] Logging
f390b13 [Patrick Wendell] Better visibility for workaround constructors
d6b0afd [Patrick Wendell] Small chang to existing constructor
403ba52 [Patrick Wendell] Style fix
870a7ba [Patrick Wendell] Work around for SI-8479
7fb13b2 [Patrick Wendell] Changes to UnionRDD and EmptyRDD
4a9e90c [Patrick Wendell] EXPERIMENTAL API --> EXPERIMENTAL
c581dce [Patrick Wendell] Changes after building against Shark.
8452309 [Patrick Wendell] Style fixes
1ed27d2 [Patrick Wendell] Formatting and coloring of badges
cd7a465 [Patrick Wendell] Code review feedback
2f706f1 [Patrick Wendell] Don't use floats
542a736 [Patrick Wendell] Small fixes
cf23ec6 [Patrick Wendell] Marking GraphX as alpha
d86818e [Patrick Wendell] Another naming change
5a76ed6 [Patrick Wendell] More visiblity clean-up
42c1f09 [Patrick Wendell] Using better labels
9d48cbf [Patrick Wendell] Initial pass

1 files changed, 26 insertions, 0 deletions

diff --git a/docs/js/api-docs.js b/docs/js/api-docs.js
new file mode 100644
index 0000000000..1414b6d0b8
--- /dev/null
+++ b/docs/js/api-docs.js
@@ -0,0 +1,26 @@
+/* Dynamically injected post-processing code for the API docs */
+
+$(document).ready(function() {
+  var annotations = $("dt:contains('Annotations')").next("dd").children("span.name");
+  addBadges(annotations, "AlphaComponent", ":: AlphaComponent ::", "<span class='alphaComponent badge'>Alpha Component</span>");
+  addBadges(annotations, "DeveloperApi", ":: DeveloperApi ::", "<span class='developer badge'>Developer API</span>");
+  addBadges(annotations, "Experimental", ":: Experimental ::", "<span class='experimental badge'>Experimental</span>");
+});
+
+function addBadges(allAnnotations, name, tag, html) {
+  var annotations = allAnnotations.filter(":contains('" + name + "')")
+  var tags = $(".cmt:contains(" + tag + ")")
+
+  // Remove identifier tags from comments
+  tags.each(function(index) {
+    var oldHTML = $(this).html();
+    var newHTML = oldHTML.replace(tag, "");
+    $(this).html(newHTML);
+  });
+
+  // Add badges to all containers
+  tags.prevAll("h4.signature")
+    .add(annotations.closest("div.fullcommenttop"))
+    .add(annotations.closest("div.fullcomment").prevAll("h4.signature"))
+    .prepend(html);
+}