[FLINK-5363] Clarify Trigger behaviour for empty windows
Project: http://git-wip-us.apache.org/repos/asf/flink/repo Commit: http://git-wip-us.apache.org/repos/asf/flink/commit/5c43d2b8 Tree: http://git-wip-us.apache.org/repos/asf/flink/tree/5c43d2b8 Diff: http://git-wip-us.apache.org/repos/asf/flink/diff/5c43d2b8 Branch: refs/heads/master Commit: 5c43d2b8ab6a1240d4692093cfa3d4b4abf2a864 Parents: fdce4b2 Author: Aljoscha Krettek <aljoscha.kret...@gmail.com> Authored: Wed Jul 11 13:38:24 2018 +0200 Committer: Aljoscha Krettek <aljoscha.kret...@gmail.com> Committed: Wed Jul 11 13:38:24 2018 +0200 ---------------------------------------------------------------------- .../flink/streaming/api/windowing/triggers/TriggerResult.java | 4 ++++ 1 file changed, 4 insertions(+) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/flink/blob/5c43d2b8/flink-streaming-java/src/main/java/org/apache/flink/streaming/api/windowing/triggers/TriggerResult.java ---------------------------------------------------------------------- diff --git a/flink-streaming-java/src/main/java/org/apache/flink/streaming/api/windowing/triggers/TriggerResult.java b/flink-streaming-java/src/main/java/org/apache/flink/streaming/api/windowing/triggers/TriggerResult.java index a37777c..70f2eb1 100644 --- a/flink-streaming-java/src/main/java/org/apache/flink/streaming/api/windowing/triggers/TriggerResult.java +++ b/flink-streaming-java/src/main/java/org/apache/flink/streaming/api/windowing/triggers/TriggerResult.java @@ -22,6 +22,10 @@ package org.apache.flink.streaming.api.windowing.triggers; * Result type for trigger methods. This determines what happens with the window, * for example whether the window function should be called, or the window * should be discarded. + * + * <p>If a {@link Trigger} returns {@link #FIRE} or {@link #FIRE_AND_PURGE} but the window does not + * contain any data the window function will not be invoked, i.e. no data will be produced for the + * window. */ public enum TriggerResult {
