Github user srdo commented on a diff in the pull request:
https://github.com/apache/storm/pull/2763#discussion_r203717231
--- Diff:
storm-server/src/main/java/org/apache/storm/daemon/nimbus/Nimbus.java ---
@@ -2809,21 +2809,19 @@ public void launchServer() throws Exception {
}
});
+ //Be cautious using method reference instead of lambda.
subexpression preceding :: will be evaluated only upon evaluation
StormMetricsRegistry.registerGauge("nimbus:num-supervisors",
() -> state.supervisors(null).size());
- StormMetricsRegistry.registerGauge("nimbus:fragmented-memory",
() -> fragmentedMemory());
- StormMetricsRegistry.registerGauge("nimbus:fragmented-cpu", ()
-> fragmentedCpu());
+ StormMetricsRegistry.registerGauge("nimbus:fragmented-memory",
this::fragmentedMemory);
+ StormMetricsRegistry.registerGauge("nimbus:fragmented-cpu",
this::fragmentedCpu);
StormMetricsRegistry.registerGauge("nimbus:available-memory",
() -> nodeIdToResources.get().values().parallelStream()
-
.mapToDouble(
-
SupervisorResources::getAvailableMem)
-
.sum());
- StormMetricsRegistry.registerGauge("nimbus:available-cpu", ()
-> nodeIdToResources.get().values().parallelStream().mapToDouble(
- SupervisorResources::getAvailableCpu).sum());
+ .mapToDouble(SupervisorResources::getAvailableMem).sum());
--- End diff --
Nit: I think the readability of method chaining is improved by having one
call per line, e.g.
```
x.stream
.map
.collect
```
rather than
```
x.stream
.map.collect
```
It's a super minor complaint though.
---
