Add std, mean to StandardScalerModel
getVectors, findSynonyms to Word2Vec Model
setFeatures and getFeatures to hashingTF

Author: MechCoder <manojkumarsivaraj334@gmail.com>

Closes #7086 from MechCoder/missing_model_methods and squashes the following commits:

9fbae90 [MechCoder] Add type
6e3d6b2 [MechCoder] [SPARK-8704] Add missing methods in StandardScaler (ML and PySpark)

Distributed generation of single-consequent association rules from a RDD of frequent itemsets. Tests referenced against `R`'s implementation of A Priori in [arules](http://cran.r-project.org/web/packages/arules/index.html).

Author: Feynman Liang <fliang@databricks.com>

Closes #7005 from feynmanliang/fp-association-rules-distributed and squashes the following commits:

466ced0 [Feynman Liang] Refactor AR generation impl
73c1cff [Feynman Liang] Make rule attributes public, remove numTransactions from FreqItemset
80f63ff [Feynman Liang] Change default confidence and optimize imports
04cf5b5 [Feynman Liang] Code review with @mengxr, add R to tests
0cc1a6a [Feynman Liang] Java compatibility test
f3c14b5 [Feynman Liang] Fix MiMa test
764375e [Feynman Liang] Fix tests
1187307 [Feynman Liang] Almost working tests
b20779b [Feynman Liang] Working implementation
5395c4e [Feynman Liang] Fix imports
2d34405 [Feynman Liang] Partial implementation of distributed ar
83ace4b [Feynman Liang] Local rule generation without pruning complete
69c2c87 [Feynman Liang] Working local implementation, now to parallelize../..
4e1ec9a [Feynman Liang] Pull FreqItemsets out, refactor type param, tests
69ccedc [Feynman Liang] First implementation of association rule generation

Otherwise the script will crash with

    - Downloading boto...
    Traceback (most recent call last):
      File "ec2/spark_ec2.py", line 148, in <module>
        setup_external_libs(external_libs)
      File "ec2/spark_ec2.py", line 128, in setup_external_libs
        if hashlib.md5(tar.read()).hexdigest() != lib["md5"]:
      File "/usr/lib/python3.4/codecs.py", line 319, in decode
        (result, consumed) = self._buffer_decode(data, self.errors, final)
    UnicodeDecodeError: 'utf-8' codec can't decode byte 0x8b in position 1: invalid start byte

In case of an utf8 env setting.

Author: Simon Hafner <hafnersimon@gmail.com>

Closes #7215 from reactormonk/branch-1.4 and squashes the following commits:

e86957a [Simon Hafner] [SPARK-8821] [EC2] Switched to binary mode

(cherry picked from commit 83a621a5)
Signed-off-by: Shivaram Venkataraman <shivaram@cs.berkeley.edu>

Follow up for https://github.com/apache/spark/pull/5946

Currently we iterate over indices and values in SparseVector and can be vectorized.

Author: MechCoder <manojkumarsivaraj334@gmail.com>

Closes #7222 from MechCoder/sparse_optim and squashes the following commits:

dcb51d3 [MechCoder] [SPARK-8823] [MLlib] [PySpark] Optimizations for SparseVector dot product

Add numNodes and depth to treeModels, add treeWeights to ensemble Models.
Add __repr__ to all models.

Author: MechCoder <manojkumarsivaraj334@gmail.com>

Closes #7095 from MechCoder/missing_methods_tree and squashes the following commits:

23b08be [MechCoder] private [spark]
38a0860 [MechCoder] rename pyTreeWeights to javaTreeWeights
6d16ad8 [MechCoder] Fix Python 3 Error
47d7023 [MechCoder] Use np.allclose and treeEnsembleModel -> TreeEnsembleMethods
819098c [MechCoder] [SPARK-8711] [ML] Add additional methods ot PySpark ML tree models

Updated MLlib Data Types Local Matrix section to include information on sparse matrices, added sparse matrix examples to the Scala and Java examples, and added Python examples for both dense and sparse matrices.

Author: Mike Dusenberry <mwdusenb@us.ibm.com>

Closes #6958 from dusenberrymw/Improve_MLlib_Local_Matrix_Documentation and squashes the following commits:

ceae407 [Mike Dusenberry] Updated MLlib Data Types Local Matrix section to include information on sparse matrices, added sparse matrix examples to the Scala and Java examples, and added Python examples for both dense and sparse matrices.

Add Java unit test for PCA transformer

Author: Yanbo Liang <ybliang8@gmail.com>

Closes #7184 from yanboliang/spark-8788 and squashes the following commits:

9d1a2af [Yanbo Liang] address comments
b34451f [Yanbo Liang] Add Java unit test for PCA transformer

(This finishes the job by removing the version overridden by Hadoop profiles.)

See discussion at https://github.com/apache/spark/pull/6994#issuecomment-119113167

Author: Sean Owen <sowen@cloudera.com>

Closes #7261 from srowen/SPARK-6731.2 and squashes the following commits:

5a3f59e [Sean Owen] Finish updating Commons Math3 to 3.4.1 from 3.1.1

when publishing releases. We named it as 'release-profile' because that is
the Maven convention. However, it turns out this special name causes several
other things to kick-in when we are creating releases that are not desirable.
For instance, it triggers the javadoc plugin to run, which actually fails
in our current build set-up.

The fix is just to rename this to a different profile to have no
collateral damage associated with its use.

[SPARK-8759][SQL] add default eval to binary and unary expression according to default behavior of nullable

We have `nullSafeCodeGen` to provide default code generation for binary and unary expression, and we can do the same thing for `eval`.

Author: Wenchen Fan <cloud0fan@outlook.com>

Closes #7157 from cloud-fan/refactor and squashes the following commits:

f3987c6 [Wenchen Fan] refactor Expression

See the jira https://issues.apache.org/jira/browse/SPARK-5562

Author: Alok  Singh <singhal@Aloks-MacBook-Pro.local>
Author: Alok  Singh <singhal@aloks-mbp.usca.ibm.com>
Author: Alok Singh <“singhal@us.ibm.com”>

Closes #7064 from aloknsingh/aloknsingh_SPARK-5562 and squashes the following commits:

259a0a7 [Alok Singh] change as per the comments by @jkbradley
be48491 [Alok  Singh] [SPARK-5562][MLlib] re-order import in alphabhetical order
c01311b [Alok  Singh] [SPARK-5562][MLlib] fix the newline typo
b271c8a [Alok  Singh] [SPARK-5562][Mllib] As per github discussion with jkbradley. We would like to simply things.
7c06251 [Alok  Singh] [SPARK-5562][MLlib] modified the JavaLDASuite for test passing
c710cb6 [Alok  Singh] fix the scala code style to have space after :
2572a08 [Alok  Singh] [SPARK-5562][MLlib] change the import xyz._ to the import xyz.{c1, c2} ..
ab55fbf [Alok  Singh] [SPARK-5562][MLlib] Change as per Sean Owen's comments https://github.com/apache/spark/pull/7064/files#diff-9236d23975e6f5a5608ffc81dfd79146
9f4f9ea [Alok  Singh] [SPARK-5562][MLlib] LDA should handle empty document.

The current implementation can't handle List<> as a return type in Hive UDF and
throws meaningless Match Error.
We assume an UDF below;
public class UDFToListString extends UDF {
public List<String> evaluate(Object o)
{ return Arrays.asList("xxx", "yyy", "zzz"); }
}
An exception of scala.MatchError is thrown as follows when the UDF used;
scala.MatchError: interface java.util.List (of class java.lang.Class)
at org.apache.spark.sql.hive.HiveInspectors$class.javaClassToDataType(HiveInspectors.scala:174)
at org.apache.spark.sql.hive.HiveSimpleUdf.javaClassToDataType(hiveUdfs.scala:76)
at org.apache.spark.sql.hive.HiveSimpleUdf.dataType$lzycompute(hiveUdfs.scala:106)
at org.apache.spark.sql.hive.HiveSimpleUdf.dataType(hiveUdfs.scala:106)
at org.apache.spark.sql.catalyst.expressions.Alias.toAttribute(namedExpressions.scala:131)
at org.apache.spark.sql.catalyst.planning.PhysicalOperation$$anonfun$collectAliases$1.applyOrElse(patterns.scala:95)
at org.apache.spark.sql.catalyst.planning.PhysicalOperation$$anonfun$collectAliases$1.applyOrElse(patterns.scala:94)
at scala.runtime.AbstractPartialFunction.apply(AbstractPartialFunction.scala:33)
at scala.collection.TraversableLike$$anonfun$collect$1.apply(TraversableLike.scala:278)
...
To make udf developers more understood, we need to throw a more suitable exception.

Author: Takeshi YAMAMURO <linguin.m.s@gmail.com>

Closes #7248 from maropu/FixBugInHiveInspectors and squashes the following commits:

1c3df2a [Takeshi YAMAMURO] Fix comments
56305de [Takeshi YAMAMURO] Fix conflicts
92ed7a6 [Takeshi YAMAMURO] Throw an exception when java list type used
2844a8e [Takeshi YAMAMURO] Apply comments
7114a47 [Takeshi YAMAMURO] Add TODO comments in UDFToListString of HiveUdfSuite
fdb2ae4 [Takeshi YAMAMURO] Add StringToUtf8 to comvert String into UTF8String
af61f2e [Takeshi YAMAMURO] Remove a new type
7f812fd [Takeshi YAMAMURO] Fix code-style errors
6984bf4 [Takeshi YAMAMURO] Apply review comments
93e3d4e [Takeshi YAMAMURO] Add a blank line at the end of UDFToListString
ee232db [Takeshi YAMAMURO] Support List as a return type in Hive UDF
1e82316 [Takeshi YAMAMURO] Apply comments
21e8763 [Takeshi YAMAMURO] Add TODO comments in UDFToListString of HiveUdfSuite
a488712 [Takeshi YAMAMURO] Add StringToUtf8 to comvert String into UTF8String
1c7b9d1 [Takeshi YAMAMURO] Remove a new type
f965c34 [Takeshi YAMAMURO] Fix code-style errors
9406416 [Takeshi YAMAMURO] Apply review comments
e21ce7e [Takeshi YAMAMURO] Add a blank line at the end of UDFToListString
e553f10 [Takeshi YAMAMURO] Support List as a return type in Hive UDF

This reverts commit 82cf3315.

Conflicts:
	pom.xml

This is a workaround for MSHADE-148, which leads to an infinite loop when building Spark with maven 3.3.x. This was originally caused by #6441, which added a bunch of test dependencies on the spark-core test module. Recently, it was revealed by #7193.

This patch adds a `-Prelease` profile. If present, it will set `createDependencyReducedPom` to true. The consequences are:
- If you are releasing Spark with this profile, you are fine as long as you use maven 3.2.x or before.
- If you are releasing Spark without this profile, you will run into SPARK-8781.
- If you are not releasing Spark but you are using this profile, you may run into SPARK-8819.
- If you are not releasing Spark and you did not include this profile, you are fine.

This is all documented in `pom.xml` and tested locally with both versions of maven.

Author: Andrew Or <andrew@databricks.com>

Closes #7219 from andrewor14/fix-maven-build and squashes the following commits:

1d37e87 [Andrew Or] Merge branch 'master' of github.com:apache/spark into fix-maven-build
3574ae4 [Andrew Or] Review comments
f39199c [Andrew Or] Create a -Prelease profile that flags `createDependencyReducedPom`

JIRA: https://issues.apache.org/jira/browse/SPARK-8463

Currently, at the reading path, `DriverRegistry` is used to load needed jdbc driver at executors. However, at the writing path, we also need `DriverRegistry` to load jdbc driver.

Author: Liang-Chi Hsieh <viirya@gmail.com>

Closes #6900 from viirya/jdbc_write_driver and squashes the following commits:

16cd04b [Liang-Chi Hsieh] Use DriverRegistry to load jdbc driver at writing path.

Adding a function checkConstraints which will check for the constraints to be applied on the dataframe / dataframe schema. Function called before storing the dataframe to an external storage. Function added in the corresponding datasource API.
cc rxin marmbrus

Author: animesh <animesh@apache.spark>

This patch had conflicts when merged, resolved by
Committer: Michael Armbrust <michael@databricks.com>

Closes #7013 from animeshbaranawal/8072 and squashes the following commits:

f70dd0e [animesh] Change IO exception to Analysis Exception
fd45e1b [animesh] 8072: Fix Style Issues
a8a964f [animesh] 8072: Improving on previous commits
3cc4d2c [animesh] Fix Style Issues
1a89115 [animesh] Fix Style Issues
98b4399 [animesh] 8072 : Moved the exception handling to ResolvedDataSource specific to parquet format
7c3d928 [animesh] 8072: Adding check to DataFrameWriter.scala

This PR adds regression test for https://issues.apache.org/jira/browse/SPARK-8588 (fixed by https://github.com/apache/spark/commit/457d07eaa023b44b75344110508f629925eb6247).

Author: Yin Huai <yhuai@databricks.com>

This patch had conflicts when merged, resolved by
Committer: Michael Armbrust <michael@databricks.com>

Closes #7103 from yhuai/SPARK-8588-test and squashes the following commits:

eb5f418 [Yin Huai] Add a query test.
c61a173 [Yin Huai] Regression test for SPARK-8588.

PySpark PowerIterationClustering test failure due to bad demo data.
If the data is small,  PowerIterationClustering will behavior indeterministic.

Author: Yanbo Liang <ybliang8@gmail.com>

Closes #7177 from yanboliang/spark-8765 and squashes the following commits:

392ae54 [Yanbo Liang] fix model.assignments output
5ec3f1e [Yanbo Liang] fix PySpark PowerIterationClustering test issue

This reverts commit 25f574eb. After speaking to some users and developers, we realized that FP-growth doesn't meet the requirement for frequent sequence mining. PrefixSpan (SPARK-6487) would be the correct algorithm for it. feynmanliang

Author: Xiangrui Meng <meng@databricks.com>

Closes #7240 from mengxr/SPARK-7212.revert and squashes the following commits:

2b3d66b [Xiangrui Meng] Revert "[SPARK-7212] [MLLIB] Add sequence learning flag"

[SPARK-6707] [CORE] [MESOS] Mesos Scheduler should allow the user to specify constraints based on slave attributes

Currently, the mesos scheduler only looks at the 'cpu' and 'mem' resources when trying to determine the usablility of a resource offer from a mesos slave node. It may be preferable for the user to be able to ensure that the spark jobs are only started on a certain set of nodes (based on attributes).

For example, If the user sets a property, let's say `spark.mesos.constraints` is set to `tachyon=true;us-east-1=false`, then the resource offers will be checked to see if they meet both these constraints and only then will be accepted to start new executors.

Author: Ankur Chauhan <achauhan@brightcove.com>

Closes #5563 from ankurcha/mesos_attribs and squashes the following commits:

902535b [Ankur Chauhan] Fix line length
d83801c [Ankur Chauhan] Update code as per code review comments
8b73f2d [Ankur Chauhan] Fix imports
c3523e7 [Ankur Chauhan] Added docs
1a24d0b [Ankur Chauhan] Expand scope of attributes matching to include all data types
482fd71 [Ankur Chauhan] Update access modifier to private[this] for offer constraints
5ccc32d [Ankur Chauhan] Fix nit pick whitespace
1bce782 [Ankur Chauhan] Fix nit pick whitespace
c0cbc75 [Ankur Chauhan] Use offer id value for debug message
7fee0ea [Ankur Chauhan] Add debug statements
fc7eb5b [Ankur Chauhan] Fix import codestyle
00be252 [Ankur Chauhan] Style changes as per code review comments
662535f [Ankur Chauhan] Incorporate code review comments + use SparkFunSuite
fdc0937 [Ankur Chauhan] Decline offers that did not meet criteria
67b58a0 [Ankur Chauhan] Add documentation for spark.mesos.constraints
63f53f4 [Ankur Chauhan] Update codestyle - uniform style for config values
02031e4 [Ankur Chauhan] Fix scalastyle warnings in tests
c09ed84 [Ankur Chauhan] Fixed the access modifier on offerConstraints val to private[mesos]
0c64df6 [Ankur Chauhan] Rename overhead fractions to memory_*, fix spacing
8cc1e8f [Ankur Chauhan] Make exception message more explicit about the source of the error
addedba [Ankur Chauhan] Added test case for malformed constraint string
ec9d9a6 [Ankur Chauhan] Add tests for parse constraint string
72fe88a [Ankur Chauhan] Fix up tests + remove redundant method override, combine utility class into new mesos scheduler util trait
92b47fd [Ankur Chauhan] Add attributes based constraints support to MesosScheduler

Spark standalone master web UI show "Alive Workers" total core, total used cores and "Alive workers" total memory, memory used.
But the JSON API page "http://MASTERURL:8088/json" shows "ALL workers"  core, memory number.
This webUI data is not sync with the JSON API.
The proper way is to sync the number with webUI and JSON API.

Author: Wisely Chen <wiselychen@appier.com>

Closes #7038 from thegiive/SPARK-8656 and squashes the following commits:

9e54bf0 [Wisely Chen] Change variable name to camel case
2c8ea89 [Wisely Chen] Change some styling and add local variable
431d2b0 [Wisely Chen] Worker List should contain DEAD node also
8b3b8e8 [Wisely Chen] [SPARK-8656] Fix the webUI and JSON API number is not synced

Author: Daoyuan Wang <daoyuan.wang@intel.com>

Closes #7234 from adrian-wang/exchangeclean and squashes the following commits:

b093ec9 [Daoyuan Wang] remove unused code

This pull request
(1) extracts common functions used by hash outer joins and put it in interface HashOuterJoin
(2) adds ShuffledHashOuterJoin and BroadcastHashOuterJoin
(3) adds test cases for shuffled and broadcast hash outer join
(3) makes SparkPlanTest to support binary or more complex operators, and fixes bugs in plan composition in SparkPlanTest

Author: kai <kaizeng@eecs.berkeley.edu>

Closes #7162 from kai-zeng/outer and squashes the following commits:

3742359 [kai] Fix not-serializable exception for code-generated keys in broadcasted relations
14e4bf8 [kai] Use CanBroadcast in broadcast outer join planning
dc5127e [kai] code style fixes
b5a4efa [kai] (1) Add broadcast hash outer join, (2) Fix SparkPlanTest

Add Python API for hex/unhex,  also cleanup Hex/Unhex

Author: Davies Liu <davies@databricks.com>

Closes #7223 from davies/hex and squashes the following commits:

6f1249d [Davies Liu] no explicit rule to cast string into binary
711a6ed [Davies Liu] fix test
f9fe5a3 [Davies Liu] Merge branch 'master' of github.com:apache/spark into hex
f032fbb [Davies Liu] Merge branch 'hex' of github.com:davies/spark into hex
49e325f [Davies Liu] Merge branch 'master' of github.com:apache/spark into hex
b31fc9a [Davies Liu] Update math.scala
25156b7 [Davies Liu] address comments and fix test
c3af78c [Davies Liu] address commments
1a24082 [Davies Liu] Add Python API for hex and unhex

Just change the attribute from -PsparkR to -Psparkr

Author: Dirceu Semighini Filho <dirceu.semighini@gmail.com>

Closes #7242 from dirceusemighini/patch-1 and squashes the following commits:

fad5991 [Dirceu Semighini Filho] Small update in the readme file

Author: Wenchen Fan <cloud0fan@outlook.com>

Closes #7237 from cloud-fan/parser and squashes the following commits:

e7b49bb [Wenchen Fan] support using keyword in column name

Here are more examples on SparkR DataFrames including creating a Spark Contect and a SQL
context, loading data and simple data manipulation.

Author: Daniel Emaasit (PhD Student) <daniel.emaasit@gmail.com>

Closes #6668 from Emaasit/dan-dev and squashes the following commits:

3a97867 [Daniel Emaasit (PhD Student)] Used fewer rows for createDataFrame
f7227f9 [Daniel Emaasit (PhD Student)] Using command line arguments
a550f70 [Daniel Emaasit (PhD Student)] Used base R functions
33f9882 [Daniel Emaasit (PhD Student)] Renamed file
b6603e3 [Daniel Emaasit (PhD Student)] changed "Describe" function to "describe"
90565dd [Daniel Emaasit (PhD Student)] Deleted the getting-started file
b95a103 [Daniel Emaasit (PhD Student)] Deleted this file
cc55cd8 [Daniel Emaasit (PhD Student)] combined all the code into one .R file
c6933af [Daniel Emaasit (PhD Student)] changed variable name to SQLContext
8e0fe14 [Daniel Emaasit (PhD Student)] provided two options for creating DataFrames
2653573 [Daniel Emaasit (PhD Student)] Updates to a comment and variable name
275b787 [Daniel Emaasit (PhD Student)] Added the Apache License at the top of the file
2e8f724 [Daniel Emaasit (PhD Student)] Added the Apache License at the top of the file
486f44e [Daniel Emaasit (PhD Student)] Added the Apache License at the file
d705112 [Daniel Emaasit (PhD Student)] Created more examples on SparkR DataFrames

When pruning partitions for a query plan, a message is logged indicating what how many partitions were selected based on predicate criteria, and what percent were pruned.

The current release erroneously uses `1 - total/selected` to compute this quantity, leading to nonsense messages like "pruned -1000% partitions". The fix is simple and obvious.

Author: Steve Lindemann <steve.lindemann@engineersgatelp.com>

Closes #7227 from srlindemann/master and squashes the following commits:

c788061 [Steve Lindemann] fix percentPruned log message

Otherwise it is impossible to declare an expression supporting DecimalType.

Author: Reynold Xin <rxin@databricks.com>

Closes #7232 from rxin/typecollection-adt and squashes the following commits:

934d3d1 [Reynold Xin] [SPARK-8831][SQL] Support AbstractDataType in TypeCollection.

This is a the follow up of #6843.

Author: Cheng Hao <hao.cheng@intel.com>

Closes #7230 from chenghao-intel/str_funcs2_followup and squashes the following commits:

52cc553 [Cheng Hao] update the code as comment

[[SPARK-8549] Fix the line length of SparkR - ASF JIRA](https://issues.apache.org/jira/browse/SPARK-8549)

Author: Yu ISHIKAWA <yuu.ishikawa@gmail.com>

Closes #7204 from yu-iskw/SPARK-8549 and squashes the following commits:

6fb131a [Yu ISHIKAWA] Fix the typo
1737598 [Yu ISHIKAWA] [SPARK-8549][SparkR] Fix the line length of SparkR

Author: Joshi <rekhajoshm@gmail.com>
Author: Rekha Joshi <rekhajoshm@gmail.com>

Closes #5992 from rekhajoshm/fix/SPARK-7137 and squashes the following commits:

8c42b57 [Joshi] update checkInputColumn to print more info if needed
33ddd2e [Joshi] update checkInputColumn to print more info if needed
acf3e17 [Joshi] update checkInputColumn to print more info if needed
8993c0e [Joshi] SPARK-7137: Add checkInputColumn back to Params and print more info
e3677c9 [Rekha Joshi] Merge pull request #1 from apache/master

ping liancheng

Author: Liang-Chi Hsieh <viirya@gmail.com>

Closes #7224 from viirya/few_fix_catalystschema and squashes the following commits:

d994330 [Liang-Chi Hsieh] Minor fix for CatalystSchemaConverter.

Author: Reynold Xin <rxin@databricks.com>

Closes #7220 from rxin/SPARK-8822 and squashes the following commits:

0cda076 [Reynold Xin] Test cases.
22d0463 [Reynold Xin] Fixed type precedence.
beb2a97 [Reynold Xin] [SPARK-8822][SQL] clean up type checking in math.scala.

Author: Reynold Xin <rxin@databricks.com>

Closes #7221 from rxin/implicit-cast-tests and squashes the following commits:

64b13bd [Reynold Xin] Fixed a bug ..
489b732 [Reynold Xin] [SQL] More unit tests for implicit type cast & add simpleString to AbstractDataType.

Jira: https://issues.apache.org/jira/browse/SPARK-8270

Info: I can not build the latest master, it stucks during the build process: `[INFO] Dependency-reduced POM written at: /Users/tarek/test/spark/bagel/dependency-reduced-pom.xml`

Author: Tarek Auel <tarek.auel@googlemail.com>

Closes #7214 from tarekauel/SPARK-8270 and squashes the following commits:

ab348b9 [Tarek Auel] Merge branch 'master' into SPARK-8270
a2ad318 [Tarek Auel] [SPARK-8270] changed order of fields
d91b12c [Tarek Auel] [SPARK-8270] python fix
adbd075 [Tarek Auel] [SPARK-8270] fixed typo
23185c9 [Tarek Auel] [SPARK-8270] levenshtein distance

[SPARK-8238][SPARK-8239][SPARK-8242][SPARK-8243][SPARK-8268][SQL]Add ascii/base64/unbase64/encode/decode functions

Add `ascii`,`base64`,`unbase64`,`encode` and `decode` expressions.

Author: Cheng Hao <hao.cheng@intel.com>

Closes #6843 from chenghao-intel/str_funcs2 and squashes the following commits:

78dee7d [Cheng Hao] base 64 -> base64
9d6f9f4 [Cheng Hao] remove the toString method for expressions
ed5c19c [Cheng Hao] update code as comments
96170fc [Cheng Hao] scalastyle issues
e2df768 [Cheng Hao] remove the unused import
491ce7b [Cheng Hao] add ascii/base64/unbase64/encode/decode functions

This commit adds a set of random data generation utilities to Spark SQL, for use in its own unit tests.

- `RandomDataGenerator.forType(DataType)` returns an `Option[() => Any]` that, if defined, contains a function for generating random values for the given DataType.  The random values use the external representations for the given DataType (for example, for DateType we return `java.sql.Date` instances instead of longs).
- `DateTypeTestUtilities` defines some convenience fields for looping over instances of data types.  For example, `numericTypes` holds `DataType` instances for all supported numeric types.  These constants will help us to raise the level of abstraction in our tests.  For example, it's now very easy to write a test which is parameterized by all common data types.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #7176 from JoshRosen/sql-random-data-generators and squashes the following commits:

f71634d [Josh Rosen] Roll back ScalaCheck usage
e0d7d49 [Josh Rosen] Bump ScalaCheck version in LICENSE
89d86b1 [Josh Rosen] Bump ScalaCheck version.
0c20905 [Josh Rosen] Initial attempt at using ScalaCheck.
b55875a [Josh Rosen] Generate doubles and floats over entire possible range.
5acdd5c [Josh Rosen] Infinity and NaN are interesting.
ab76cbd [Josh Rosen] Move code to Catalyst package.
d2b4a4a [Josh Rosen] Add random data generator test utilities to Spark SQL.

Author: Daoyuan Wang <daoyuan.wang@intel.com>

Closes #6985 from adrian-wang/udfcurrent and squashes the following commits:

6a20b64 [Daoyuan Wang] remove codegen and add lazy in testsuite
27c9f95 [Daoyuan Wang] refine tests..
e11ae75 [Daoyuan Wang] refine tests
61ed3d5 [Daoyuan Wang] add in functions
98e8550 [Daoyuan Wang] fix sytle
427d9dc [Daoyuan Wang] add tests and codegen
0b69a1f [Daoyuan Wang] udf current