Add comment about protecting a collection cycle by a lock

Signed-off-by: Bogdan Cristian Drutu <[email protected]>
open-telemetry · Feb 19, 2020 · 22bd1e7 · 22bd1e7
1 parent 5a8bce6
commit 22bd1e7
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/sdk/src/main/java/io/opentelemetry/sdk/metrics/Batcher.java b/sdk/src/main/java/io/opentelemetry/sdk/metrics/Batcher.java
@@ -25,6 +25,10 @@
  * A {@code Batcher} represents an internal representation of an {code Instrument} aggregation
  * process. It records individual measurements (via the {@code Aggregator}). It batches together
  * {@code Aggregator}s for the similar {@code LabelSet}.
+ *
+ * <p>The only thread safe method in this class is {@link #getAggregator()}. An entire collection
+ * cycle must be protected by a lock. A collection cycle is defined by multiple calls to {@link
+ * #batch(LabelSet, Aggregator, boolean)} followed by one {@link #completeCollectionCycle()};
  */
 interface Batcher {