[SPARK-8214][SQL]Add function hex

[zhichao-li]

cc @chenghao-intel @adrian-wang

[adrian-wang]

remove this line.
use Converts instead of Convert

[SparkQA]

Test build #35653 has finished for PR 6976 at commit f534efc.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • case class Hex(child: Expression)
  • case class Hypot(left: Expression, right: Expression)

[SparkQA]

Test build #35664 has finished for PR 6976 at commit aaaf841.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[chenghao-intel]

remove the null checking, as it's did in eval already.

[chenghao-intel]

LGTM, except some minor issues. Can you also remove the WIP?

[SparkQA]

Test build #35818 has finished for PR 6976 at commit a647641.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • case class Hex(child: Expression)
  • case class Hypot(left: Expression, right: Expression)

[zhichao-li]

@rxin could you please take a look at this ?

[davies]

If use 'UTF8' as the encoding here, it should be str.getBytes

[zhichao-li]

would remove toString() here.

[SparkQA]

Test build #35950 has finished for PR 6976 at commit 3b2fa13.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • case class Hex(child: Expression)
  • case class Hypot(left: Expression, right: Expression)

[SparkQA]

Test build #35951 has finished for PR 6976 at commit 967ec90.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • case class Hex(child: Expression)
  • case class Hypot(left: Expression, right: Expression)

[SparkQA]

Test build #35957 has finished for PR 6976 at commit cf9c936.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • case class Hex(child: Expression)
  • case class Hypot(left: Expression, right: Expression)

[davies]

UTF8String.length is the number of code points, not the number of bytes.

[zhichao-li]

would reuse the hex(bytes) method as a work around and add a unit test which contain chinese character to cover this.

[SparkQA]

Test build #35972 has finished for PR 6976 at commit de3f5ea.

• This patch fails Scala style tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • case class Hex(child: Expression)
  • case class Hypot(left: Expression, right: Expression)

[SparkQA]

Test build #35978 has finished for PR 6976 at commit e218d1b.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • case class Hex(child: Expression)
  • case class Hypot(left: Expression, right: Expression)

[davies]

LGTM, merging this into master, thanks!