[SPARK-9893] User guide with Java test suite for VectorSlicer

[yinxusen]

Add user guide for VectorSlicer, with Java test suite and Python version VectorSlicer.

Note that Python version does not support selecting by names now.

[SparkQA]

Test build #41099 has finished for PR 8267 at commit 61092cc.

• This patch fails Python style tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • class VectorSlicer(JavaTransformer, HasInputCol, HasOutputCol):

[SparkQA]

Test build #41110 has finished for PR 8267 at commit 3ff4b5d.

• This patch fails Python style tests.
• This patch does not merge cleanly.
• This patch adds the following public classes (experimental):
  • class VectorSlicer(JavaTransformer, HasInputCol, HasOutputCol):

[SparkQA]

Test build #41113 has finished for PR 8267 at commit d5cdabd.

• This patch fails Spark unit tests.
• This patch does not merge cleanly.
• This patch adds the following public classes (experimental):
  • class VectorSlicer(JavaTransformer, HasInputCol, HasOutputCol):

[feynmanliang]

@yinxusen Sorry, I think there's some merge conflicts. Do you mind rebasing master?

[feynmanliang]

Could you also modify the title to include java tests and python API?

[feynmanliang]

I know other parts of the user guides don't do this, but we should try to keep lines to 100 characters so future diffs are smaller

[feynmanliang]

nit: _Specification_ by integer and string are both acceptable**_. M**_oreover,

[feynmanliang]

@yinxusen The documentation looks good. Only things left:

• Can you update the title of the PR to include python api and java tests?
• Do you mind resolving merge conflicts?

Thanks!

[yinxusen]

@feynmanliang Conflicts fixed.

[SparkQA]

Test build #41305 has finished for PR 8267 at commit 6d066c7.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • class VectorSlicer(JavaTransformer, HasInputCol, HasOutputCol):

[mengxr]

@yinxusen Could you split this PR into two? One for the user guide with example code and Java test suite, which can be merged into 1.5, and one implements the Python API. We count Python API as new features, and try not to merge them during QA.

[mengxr]

Do not use [] or {} as the default value in Python API, because they are mutable and shared among instances. Please use None instead. Again, we should move Python API to a separate PR.

[SparkQA]

Test build #41345 timed out for PR 8267 at commit f8f0d61 after a configured wait of 175m.

[feynmanliang]

jenkins test this please

[feynmanliang]

LGTM pending tests

[SparkQA]

Test build #41384 has finished for PR 8267 at commit f8f0d61.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • public class JavaVectorSlicerSuite

[mengxr]

Merged into master and branch-1.5. Thanks!