[SPARK-14353] Dataset Time Window `window` API for R

## What changes were proposed in this pull request?

The `window` function was added to Dataset with [this PR](https://github.com/apache/spark/pull/12008).
This PR adds the R API for this function.

With this PR, SQL, Java, and Scala will share the same APIs as in users can use:
 - `window(timeColumn, windowDuration)`
 - `window(timeColumn, windowDuration, slideDuration)`
 - `window(timeColumn, windowDuration, slideDuration, startTime)`

In Python and R, users can access all APIs above, but in addition they can do
 - In R:
   `window(timeColumn, windowDuration, startTime=...)`

that is, they can provide the startTime without providing the `slideDuration`. In this case, we will generate tumbling windows.

## How was this patch tested?

Unit tests + manual tests

Author: Burak Yavuz <brkyvz@gmail.com>

Closes #12141 from brkyvz/R-windows.

1 files changed, 36 insertions, 0 deletions

diff --git a/R/pkg/inst/tests/testthat/test_sparkSQL.R b/R/pkg/inst/tests/testthat/test_sparkSQL.R
index eef365b42e..22eb3ec984 100644
--- a/R/pkg/inst/tests/testthat/test_sparkSQL.R
+++ b/R/pkg/inst/tests/testthat/test_sparkSQL.R
@@ -1204,6 +1204,42 @@ test_that("greatest() and least() on a DataFrame", {
   expect_equal(collect(select(df, least(df$a, df$b)))[, 1], c(1, 3))
 })
 
+test_that("time windowing (window()) with all inputs", {
+  df <- createDataFrame(sqlContext, data.frame(t = c("2016-03-11 09:00:07"), v = c(1)))
+  df$window <- window(df$t, "5 seconds", "5 seconds", "0 seconds")
+  local <- collect(df)$v
+  # Not checking time windows because of possible time zone issues. Just checking that the function
+  # works
+  expect_equal(local, c(1))
+})
+
+test_that("time windowing (window()) with slide duration", {
+  df <- createDataFrame(sqlContext, data.frame(t = c("2016-03-11 09:00:07"), v = c(1)))
+  df$window <- window(df$t, "5 seconds", "2 seconds")
+  local <- collect(df)$v
+  # Not checking time windows because of possible time zone issues. Just checking that the function
+  # works
+  expect_equal(local, c(1, 1))
+})
+
+test_that("time windowing (window()) with start time", {
+  df <- createDataFrame(sqlContext, data.frame(t = c("2016-03-11 09:00:07"), v = c(1)))
+  df$window <- window(df$t, "5 seconds", startTime = "2 seconds")
+  local <- collect(df)$v
+  # Not checking time windows because of possible time zone issues. Just checking that the function
+  # works
+  expect_equal(local, c(1))
+})
+
+test_that("time windowing (window()) with just window duration", {
+  df <- createDataFrame(sqlContext, data.frame(t = c("2016-03-11 09:00:07"), v = c(1)))
+  df$window <- window(df$t, "5 seconds")
+  local <- collect(df)$v
+  # Not checking time windows because of possible time zone issues. Just checking that the function
+  # works
+  expect_equal(local, c(1))
+})
+
 test_that("when(), otherwise() and ifelse() on a DataFrame", {
   l <- list(list(a = 1, b = 2), list(a = 3, b = 4))
   df <- createDataFrame(sqlContext, l)