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, 12 insertions, 12 deletions

diff --git a/docs/_plugins/copy_api_dirs.rb b/docs/_plugins/copy_api_dirs.rb
index 2245bcbc70..bbd56d2fd1 100644
--- a/docs/_plugins/copy_api_dirs.rb
+++ b/docs/_plugins/copy_api_dirs.rb
@@ -24,7 +24,9 @@ if not (ENV['SKIP_API'] == '1' or ENV['SKIP_SCALADOC'] == '1')
   external_projects = ["flume", "kafka", "mqtt", "twitter", "zeromq"]
   sql_projects = ["catalyst", "core", "hive"]
 
-  projects = core_projects + external_projects.map { |project_name| "external/" + project_name }
+  projects = core_projects
+  projects = projects + external_projects.map { |project_name| "external/" + project_name }
+  projects = projects + sql_projects.map { |project_name| "sql/" + project_name }
 
   puts "Moving to project root and building scaladoc."
   curr_dir = pwd
@@ -42,24 +44,22 @@ if not (ENV['SKIP_API'] == '1' or ENV['SKIP_SCALADOC'] == '1')
     source = "../" + project_name + "/target/scala-2.10/api"
     dest = "api/" + project_name
 
-    puts "echo making directory " + dest
+    puts "making directory " + dest
     mkdir_p dest
 
     # From the rubydoc: cp_r('src', 'dest') makes src/dest, but this doesn't.
     puts "cp -r " + source + "/. " + dest
     cp_r(source + "/.", dest)
-  end
-
-  sql_projects.each do |project_name|
-    source = "../sql/" + project_name + "/target/scala-2.10/api/"
-    dest = "api/sql/" + project_name
 
-    puts "echo making directory " + dest
-    mkdir_p dest
+    # Append custom JavaScript
+    js = File.readlines("./js/api-docs.js")
+    js_file = dest + "/lib/template.js"
+    File.open(js_file, 'a') { |f| f.write("\n" + js.join()) }
 
-    # From the rubydoc: cp_r('src', 'dest') makes src/dest, but this doesn't.
-    puts "cp -r " + source + "/. " + dest
-    cp_r(source + "/.", dest)
+    # Append custom CSS
+    css = File.readlines("./css/api-docs.css")
+    css_file = dest + "/lib/template.css"
+    File.open(css_file, 'a') { |f| f.write("\n" + css.join()) }
   end
 
   # Build Epydoc for Python