[Bigtable] Added StreamController cancel in readRowsAsync docs (#5125)

rahulKQL · igorbernstein2 · commit 2313bb545e4b · 2019-05-10T14:41:53.000-04:00
* Added StremController cancel in readRowsAsync docs

* Updating the Sample code with better approach
diff --git a/google-cloud-clients/google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/BigtableDataClient.java b/google-cloud-clients/google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/BigtableDataClient.java
@@ -513,9 +513,16 @@ public <RowT> UnaryCallable<Query, RowT> readRowCallable(RowAdapter<RowT> rowAda
    *          .range("[START KEY]", "[END KEY]")
    *          .filter(FILTERS.qualifier().regex("[COLUMN PREFIX].*"));
    *
-   *   // Iterator style
    *   try {
-   *     for(Row row : bigtableDataClient.readRows(query)) {
+   *     ServerStream<Row> stream = bigtableDataClient.readRows(query);
+   *     int count = 0;
+   *
+   *     // Iterator style
+   *     for (Row row : stream) {
+   *       if (++count > 10) {
+   *         stream.cancel();
+   *         break;
+   *       }
    *       // Do something with row
    *     }
    *   } catch (NotFoundException e) {
@@ -548,8 +555,17 @@ public ServerStream<Row> readRows(Query query) {
    *          .filter(FILTERS.qualifier().regex("[COLUMN PREFIX].*"));
    *
    *   bigtableDataClient.readRowsAsync(query, new ResponseObserver<Row>() {
-   *     public void onStart(StreamController controller) { }
+   *     StreamController controller;
+   *     int count = 0;
+   *
+   *     public void onStart(StreamController controller) {
+   *       this.controller = controller;
+   *     }
    *     public void onResponse(Row row) {
+   *       if (++count > 10) {
+   *         controller.cancel();
+   *         return;
+   *       }
    *       // Do something with Row
    *     }
    *     public void onError(Throwable t) {
