Fixed coding style issues in Spark SQL

This PR addresses various coding style issues in Spark SQL, including but not limited to those mentioned by @mateiz in PR #146.

As this PR affects lots of source files and may cause potential conflicts, it would be better to merge this as soon as possible *after* PR #205 (In-memory columnar representation for Spark SQL) is merged.

Author: Cheng Lian <lian.cs.zju@gmail.com>

Closes #208 from liancheng/fixCodingStyle and squashes the following commits:

fc2b528 [Cheng Lian] Merge branch 'master' into fixCodingStyle
b531273 [Cheng Lian] Fixed coding style issues in sql/hive
0b56f77 [Cheng Lian] Fixed coding style issues in sql/core
fae7b02 [Cheng Lian] Addressed styling issues mentioned by @marmbrus
9265366 [Cheng Lian] Fixed coding style issues in sql/core
3dcbbbd [Cheng Lian] Fixed relative package imports for package catalyst
[SPARK-1212] Adding sparse data support and update KMeans

Continue our discussions from https://github.com/apache/incubator-spark/pull/575

This PR is WIP because it depends on a SNAPSHOT version of breeze.

Per previous discussions and benchmarks, I switched to breeze for linear algebra operations. @dlwh and I made some improvements to breeze to keep its performance comparable to the bare-bone implementation, including norm computation and squared distance. This is why this PR needs to depend on a SNAPSHOT version of breeze.

@fommil , please find the notice of using netlib-core in `NOTICE`. This is following Apache's instructions on appropriate labeling.

I'm going to update this PR to include:

1. Fast distance computation: using `\|a\|_2^2 + \|b\|_2^2 - 2 a^T b` when it doesn't introduce too much numerical error. The squared norms are pre-computed. Otherwise, computing the distance between the center (dense) and a point (possibly sparse) always takes O(n) time.

2. Some numbers about the performance.

3. A released version of breeze. @dlwh, a minor release of breeze will help this PR get merged early. Do you mind sharing breeze's release plan? Thanks!

Author: Xiangrui Meng <meng@databricks.com>

Closes #117 from mengxr/sparse-kmeans and squashes the following commits:

67b368d [Xiangrui Meng] fix SparseVector.toArray
5eda0de [Xiangrui Meng] update NOTICE
67abe31 [Xiangrui Meng] move ArrayRDDs to mllib.rdd
1da1033 [Xiangrui Meng] remove dependency on commons-math3 and compute EPSILON directly
9bb1b31 [Xiangrui Meng] optimize SparseVector.toArray
226d2cd [Xiangrui Meng] update Java friendly methods in Vectors
238ba34 [Xiangrui Meng] add VectorRDDs with a converter from RDD[Array[Double]]
b28ba2f [Xiangrui Meng] add toArray to Vector
e69b10c [Xiangrui Meng] remove examples/JavaKMeans.java, which is replaced by mllib/examples/JavaKMeans.java
72bde33 [Xiangrui Meng] clean up code for distance computation
712cb88 [Xiangrui Meng] make Vectors.sparse Java friendly
27858e4 [Xiangrui Meng] update breeze version to 0.7
07c3cf2 [Xiangrui Meng] change Mahout to breeze in doc use a simple lower bound to avoid unnecessary distance computation
6f5cdde [Xiangrui Meng] fix a bug in filtering finished runs
42512f2 [Xiangrui Meng] Merge branch 'master' into sparse-kmeans
d6e6c07 [Xiangrui Meng] add predict(RDD[Vector]) to KMeansModel
42b4e50 [Xiangrui Meng] line feed at the end
a4ace73 [Xiangrui Meng] Merge branch 'fast-dist' into sparse-kmeans
3ed1a24 [Xiangrui Meng] add doc to BreezeVectorWithSquaredNorm
0107e19 [Xiangrui Meng] update NOTICE
87bc755 [Xiangrui Meng] tuned the KMeans code: changed some for loops to while, use view to avoid copying arrays
0ff8046 [Xiangrui Meng] update KMeans to use fastSquaredDistance
f355411 [Xiangrui Meng] add BreezeVectorWithSquaredNorm case class
ab74f67 [Xiangrui Meng] add fastSquaredDistance for KMeans
4e7d5ca [Xiangrui Meng] minor style update
07ffaf2 [Xiangrui Meng] add dense/sparse vector data models and conversions to/from breeze vectors use breeze to implement KMeans in order to support both dense and sparse data
SPARK-1144 Added license and RAT to check licenses.

Author: Prashant Sharma <prashant.s@imaginea.com>

Closes #125 from ScrapCodes/rat-integration and squashes the following commits:

64f7c7d [Prashant Sharma] added license headers.
fcf28b1 [Prashant Sharma] Review feedback.
c0648db [Prashant Sharma] SPARK-1144 Added license and RAT to check licenses.
HOT FIX: Exclude test files from RAT
SPARK-1294 Fix resolution of uppercase field names using a HiveContext.

Fixing this bug required the following:
 - Creation of a new logical node that converts a schema to lowercase.
 - Generalization of the subquery eliding rule to also elide this new node
 - Fixing of several places where too tight assumptions were made on the types of `InsertIntoTable` children.
 - I also removed an API that was left in by accident that exposed catalyst data structures, and fix the logic that pushes down filters into hive tables scans to correctly compare attribute references.

Author: Michael Armbrust <michael@databricks.com>

Closes #202 from marmbrus/upperCaseFieldNames and squashes the following commits:

15e5265 [Michael Armbrust] Support for resolving mixed case fields from a reflected schema using HiveQL.
5aa5035 [Michael Armbrust] Remove API that exposes internal catalyst data structures.
9d99cb6 [Michael Armbrust] Attributes should be compared using exprId, not TreeNode.id.
SPARK-1094 Support MiMa for reporting binary compatibility accross versions.

This adds some changes on top of the initial work by @scrapcodes in #20:

The goal here is to do automated checking of Spark commits to determine whether they break binary compatibility.

1. Special case for inner classes of package-private objects.
2. Made tools classes accessible when running `spark-class`.
3. Made some declared types in MLLib more general.
4. Various other improvements to exclude-generation script.
5. In-code documentation.

Author: Patrick Wendell <pwendell@gmail.com>
Author: Prashant Sharma <prashant.s@imaginea.com>
Author: Prashant Sharma <scrapcodes@gmail.com>

Closes #207 from pwendell/mima and squashes the following commits:

22ae267 [Patrick Wendell] New binary changes after upmerge
6c2030d [Patrick Wendell] Merge remote-tracking branch 'apache/master' into mima
3666cf1 [Patrick Wendell] Minor style change
0e0f570 [Patrick Wendell] Small fix and removing directory listings
647c547 [Patrick Wendell] Reveiw feedback.
c39f3b5 [Patrick Wendell] Some enhancements to binary checking.
4c771e0 [Prashant Sharma] Added a tool to generate mima excludes and also adapted build to pick automatically.
b551519 [Prashant Sharma] adding a new exclude after rebasing with master
651844c [Prashant Sharma] Support MiMa for reporting binary compatibility accross versions.
SPARK-1128: set hadoop task properties when constructing HadoopRDD

https://spark-project.atlassian.net/browse/SPARK-1128

The task properties are not set when constructing HadoopRDD in current implementation, this may limit the implementation based on

```
mapred.tip.id
mapred.task.id
mapred.task.is.map
mapred.task.partition
mapred.job.id
```

This patch also contains a small fix  in createJobID (SparkHadoopWriter.scala), where the current implementation actually is not using time parameter

Author: CodingCat <zhunansjtu@gmail.com>
Author: Nan Zhu <CodingCat@users.noreply.github.com>

Closes #101 from CodingCat/SPARK-1128 and squashes the following commits:

ed0980f [CodingCat] make SparkHiveHadoopWriter belongs to spark package
5b1ad7d [CodingCat] move SparkHiveHadoopWriter to org.apache.spark package
258f92c [CodingCat] code cleanup
af88939 [CodingCat] update the comments and permission of SparkHadoopWriter
9bd1fe3 [CodingCat] move configuration for jobConf to HadoopRDD
b7bdfa5 [Nan Zhu] style fix
a3153a8 [Nan Zhu] style fix
c3258d2 [CodingCat] set hadoop task properties while using InputFormat
Unify the logic for column pruning, projection, and filtering of table scans.

This removes duplicated logic, dead code and casting when planning parquet table scans and hive table scans.

Other changes:
 - Fix tests now that we are doing a better job of column pruning (i.e., since pruning predicates are applied before we even start scanning tuples, columns required by these predicates do not need to be included in the output of the scan unless they are also included in the final output of this logical plan fragment).
 - Add rule to simplify trivial filters.  This was required to avoid `WHERE false` from getting pushed into table scans, since `HiveTableScan` (reasonably) refuses to apply partition pruning predicates to non-partitioned tables.

Author: Michael Armbrust <michael@databricks.com>

Closes #213 from marmbrus/strategyCleanup and squashes the following commits:

48ce403 [Michael Armbrust] Move one more bit of parquet stuff into the core SQLContext.
834ce08 [Michael Armbrust] Address comments.
0f2c6f5 [Michael Armbrust] Unify the logic for column pruning, projection, and filtering of table scans for both Hive and Parquet relations.  Fix tests now that we are doing a better job of column pruning.
SPARK-1286: Make usage of spark-env.sh idempotent

Various spark scripts load spark-env.sh. This can cause growth of any variables that may be appended to (SPARK_CLASSPATH, SPARK_REPL_OPTS) and it makes the precedence order for options specified in spark-env.sh less clear.

One use-case for the latter is that we want to set options from the command-line of spark-shell, but these options will be overridden by subsequent loading of spark-env.sh. If we were to load the spark-env.sh first and then set our command-line options, we could guarantee correct precedence order.

Note that we use SPARK_CONF_DIR if available to support the sbin/ scripts, which always set this variable from sbin/spark-config.sh. Otherwise, we default to the ../conf/ as usual.

Author: Aaron Davidson <aaron@databricks.com>

Closes #184 from aarondav/idem and squashes the following commits:

e291f91 [Aaron Davidson] Use "private" variables in load-spark-env.sh
8da8360 [Aaron Davidson] Add .sh extension to load-spark-env.sh
93a2471 [Aaron Davidson] SPARK-1286: Make usage of spark-env.sh idempotent
Add more hive compatability tests to whitelist

Author: Michael Armbrust <michael@databricks.com>

Closes #220 from marmbrus/moreTests and squashes the following commits:

223ec35 [Michael Armbrust] Blacklist machine specific test
9c966cc [Michael Armbrust] add more hive compatability tests to whitelist
SPARK-1316. Remove use of Commons IO

(This follows from a side point on SPARK-1133, in discussion of the PR: https://github.com/apache/spark/pull/164 )

Commons IO is barely used in the project, and can easily be replaced with equivalent calls to Guava or the existing Spark `Utils.scala` class.

Removing a dependency feels good, and this one in particular can get a little problematic since Hadoop uses it too.

Author: Sean Owen <sowen@cloudera.com>

Closes #226 from srowen/SPARK-1316 and squashes the following commits:

21efef3 [Sean Owen] Remove use of Commons IO
SPARK-1319: Fix scheduler to account for tasks using > 1 CPUs.

Move CPUS_PER_TASK to TaskSchedulerImpl as the value is a constant and use it in both Mesos and CoarseGrained scheduler backends.

Thanks @kayousterhout for the design discussion

Author: Shivaram Venkataraman <shivaram@eecs.berkeley.edu>

Closes #219 from shivaram/multi-cpus and squashes the following commits:

5c7d685 [Shivaram Venkataraman] Don't pass availableCpus to TaskSetManager
260e4d5 [Shivaram Venkataraman] Add a check for non-zero CPUs in TaskSetManager
73fcf6f [Shivaram Venkataraman] Add documentation for spark.task.cpus
647bc45 [Shivaram Venkataraman] Fix scheduler to account for tasks using > 1 CPUs. Move CPUS_PER_TASK to TaskSchedulerImpl as the value is a constant and use it in both Mesos and CoarseGrained scheduler backends.
Avoid Option while generating call site

This is an update on https://github.com/apache/spark/pull/180, which changes the solution from blacklisting "Option.scala" to avoiding the Option code path while generating the call path.

Also includes a unit test to prevent this issue in the future, and some minor refactoring.

Thanks @witgo for reporting this issue and working on the initial solution!

Author: witgo <witgo@qq.com>
Author: Aaron Davidson <aaron@databricks.com>

Closes #222 from aarondav/180 and squashes the following commits:

f74aad1 [Aaron Davidson] Avoid Option while generating call site & add unit tests
d2b4980 [witgo] Modify the position of the filter
1bc22d7 [witgo] Fix Stage.name return "apply at Option.scala:120"
Initial experimentation with Travis CI configuration

This is not intended to replace Jenkins immediately, and Jenkins will remain the CI of reference for merging pull requests in the near term.  Long term, it is possible that Travis will give us better integration with github, so we are investigating its use.

Author: Michael Armbrust <michael@databricks.com>

Closes #230 from marmbrus/travis and squashes the following commits:

93f9a32 [Michael Armbrust] Add Apache license to .travis.yml
d7c0e78 [Michael Armbrust] Initial experimentation with Travis CI configuration
SPARK-1321 Use Guava's top k implementation rather than our BoundedPriorityQueue based implementation

Also updated the documentation for top and takeOrdered.

On my simple test of sorting 100 million (Int, Int) tuples using Spark, Guava's top k implementation (in Ordering) is much faster than the BoundedPriorityQueue implementation for roughly sorted input (10 - 20X faster), and still faster for purely random input (2 - 5X).

Author: Reynold Xin <rxin@apache.org>

Closes #229 from rxin/takeOrdered and squashes the following commits:

0d11844 [Reynold Xin] Use Guava's top k implementation rather than our BoundedPriorityQueue based implementation. Also updated the documentation for top and takeOrdered.
SPARK-1322, top in pyspark should sort result in descending order.

Author: Prashant Sharma <prashant.s@imaginea.com>

Closes #235 from ScrapCodes/SPARK-1322/top-rev-sort and squashes the following commits:

f316266 [Prashant Sharma] Minor change in comment.
58e58c6 [Prashant Sharma] SPARK-1322, top in pyspark should sort result in descending order.
Unified package definition format in Spark SQL

According to discussions in comments of PR #208, this PR unifies package definition format in Spark SQL.

Some broken links in ScalaDoc and typos detected along the way are also fixed.

Author: Cheng Lian <lian.cs.zju@gmail.com>

Closes #225 from liancheng/packageDefinition and squashes the following commits:

75c47b3 [Cheng Lian] Fixed file line length
4f87968 [Cheng Lian] Unified package definition format in Spark SQL
[SQL] Un-ignore a test that is now passing.

Add golden answer for aforementioned test.

Also, fix golden test generation from sbt/sbt by setting the classpath correctly.

Author: Michael Armbrust <michael@databricks.com>

Closes #244 from marmbrus/partTest and squashes the following commits:

37a33c9 [Michael Armbrust] Un-ignore a test that is now passing, add golden answer for aforementioned test.  Fix golden test generation from sbt/sbt.
[SQL] Add a custom serializer for maps since they do not have a no-arg constructor.

Author: Michael Armbrust <michael@databricks.com>

Closes #243 from marmbrus/mapSer and squashes the following commits:

54045f7 [Michael Armbrust] Add a custom serializer for maps since they do not have a no-arg constructor.
SPARK-1324: SparkUI Should Not Bind to SPARK_PUBLIC_DNS

/cc @aarondav and @andrewor14

Author: Patrick Wendell <pwendell@gmail.com>

Closes #231 from pwendell/ui-binding and squashes the following commits:

e8025f8 [Patrick Wendell] SPARK-1324: SparkUI Should Not Bind to SPARK_PUBLIC_DNS