fixing the NoSuchElementException when availability of the underlying…

… table is empty (#702)

CHANGELOG.md

@@ -27,6 +27,8 @@ pull request if there was one.
 
 ### Fixed:
 
+- [Fix generate intervals logic when availability is empty](https://github.com/yahoo/fili/pull/702)
+    * Logic to generate intervals when `CURRENT_MACRO_USES_LATEST` flag is turned on has a bug. The code throws `NoSuchElementException` when the table has no availabilities. This PR fixes the bug by checking if the availability of the underlying table is empty.
 - [Correct Druid coordinator URL in Wikipedia example](https://github.com/yahoo/fili/pull/683)
     * Config value for Druid coordinator URL is mis-typed.
 
@@ -156,8 +158,10 @@ Thanks to everyone who contributed to this release!
 
 ### Added:
 
-- [Logical Table Availability](https://github.com/yahoo/fili/pull/697)
-    * Added `logicalTableAvailability` to `TableUtils` which returns the union of availabilities for the logical table.
+- [Latest Time Macro](https://github.com/yahoo/fili/pull/697)
+    * Added `logicalTableAvailability` to `TableUtils` which returns the union of intervals for the logical table.
+    * Added `now` parameter to `generateIntervals` for which time macros will be relatively calculated.
+    * Added `CURRENT_MACRO_USES_LATEST` flag which when turned on uses the first unavailable availability to generate the intervals. 
 
 - [Annotate Functional Interface](https://github.com/yahoo/fili/pull/606)
     * Add `@FunctionalInterface` annotation to all functional interfaces.

fili-core/src/main/java/com/yahoo/bard/webservice/web/apirequest/DataApiRequestImpl.java

@@ -39,6 +39,7 @@
 import com.yahoo.bard.webservice.table.LogicalTable;
 import com.yahoo.bard.webservice.table.LogicalTableDictionary;
 import com.yahoo.bard.webservice.table.TableIdentifier;
+import com.yahoo.bard.webservice.util.SimplifiedIntervalList;
 import com.yahoo.bard.webservice.util.StreamUtils;
 import com.yahoo.bard.webservice.util.TableUtils;
 import com.yahoo.bard.webservice.web.ApiFilter;
@@ -297,9 +298,14 @@ public DataApiRequestImpl(
         DateTimeFormatter dateTimeFormatter = generateDateTimeFormatter(timeZone);
 
         if (BardFeatureFlag.CURRENT_MACRO_USES_LATEST.isOn()) {
-            DateTime firstUnavailableInstant = TableUtils.logicalTableAvailability(getTable()).getLast().getEnd();
-            DateTime adjustedNow =  firstUnavailableInstant.isBeforeNow() ? firstUnavailableInstant : new DateTime();
-
+            SimplifiedIntervalList availability =  TableUtils.logicalTableAvailability(getTable());
+            DateTime adjustedNow = new DateTime();
+            if (! availability.isEmpty()) {
+                DateTime firstUnavailable =  availability.getLast().getEnd();
+                if (firstUnavailable.isBeforeNow()) {
+                    adjustedNow = firstUnavailable;
+                }
+            }
             this.intervals = generateIntervals(adjustedNow, intervals, this.granularity, dateTimeFormatter);
         } else {
             this.intervals = generateIntervals(intervals, this.granularity, dateTimeFormatter);