From deb56539fbf458f73630161431767cced0ca5003 Mon Sep 17 00:00:00 2001
From: Winston Chang <winston@stdout.org>
Date: Tue, 25 Apr 2017 10:48:29 -0500
Subject: [PATCH] Better reactivePoll example. Closes #1678

---
 R/reactives.R       | 17 +++++++++++++++--
 man/reactivePoll.Rd | 17 +++++++++++++++--
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/R/reactives.R b/R/reactives.R
index c41948e6f..53bddcadc 100644
--- a/R/reactives.R
+++ b/R/reactives.R
@@ -1541,9 +1541,22 @@ coerceToFunc <- function(x) {
 #' @seealso \code{\link{reactiveFileReader}}
 #'
 #' @examples
-#' # Assume the existence of readTimestamp and readValue functions
 #' function(input, output, session) {
-#'   data <- reactivePoll(1000, session, readTimestamp, readValue)
+#'
+#'   data <- reactivePoll(1000, session,
+#'     # This function returns the time that log_file was last modified
+#'     checkFunc = function() {
+#'       if (file.exists(log_file))
+#'         file.info(log_file)$mtime[1]
+#'       else
+#'         ""
+#'     },
+#'     # This function returns the content of log_file
+#'     valueFunc = function() {
+#'       read.csv(log_file)
+#'     }
+#'   )
+#'
 #'   output$dataTable <- renderTable({
 #'     data()
 #'   })
diff --git a/man/reactivePoll.Rd b/man/reactivePoll.Rd
index 9f2602281..daa2f335a 100644
--- a/man/reactivePoll.Rd
+++ b/man/reactivePoll.Rd
@@ -57,9 +57,22 @@ will be executed in a reactive context; therefore, they may read reactive
 values and reactive expressions.
 }
 \examples{
-# Assume the existence of readTimestamp and readValue functions
 function(input, output, session) {
-  data <- reactivePoll(1000, session, readTimestamp, readValue)
+
+  data <- reactivePoll(1000, session,
+    # This function returns the time that log_file was last modified
+    checkFunc = function() {
+      if (file.exists(log_file))
+        file.info(log_file)$mtime[1]
+      else
+        ""
+    },
+    # This function returns the content of log_file
+    valueFunc = function() {
+      read.csv(log_file)
+    }
+  )
+
   output$dataTable <- renderTable({
     data()
   })