[FLINK-6053] Gauge<T> should only take subclasses of Number, rather than everything

• Type: Sub-task
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 1.2.0
• Fix Version/s: 2.0.0
• Component/s: Runtime / Metrics
• Labels: 2.0-related pull-request-available
• Assignee: Unassigned
• Reporter: Bowen Li
• Created: 14/Mar/17 22:12
• Updated: 05/Dec/23 06:44

Description

Currently, Flink's Gauge is defined as

```java
public interface Gauge<T> extends Metric {
T getValue();
}
```

But it doesn't make sense to have Gauge take generic types other than Number. And it blocks I from finishing FLINK-6013, because I cannot assume Gauge is only about Number. So the class should be like

```java
public interface Gauge<T extends Number> extends Metric {
T getValue();
}
```

Issue Links

• is blocked by: FLINK-7608 LatencyGauge change to histogram metric
• is related to: FLINK-5095 Add explicit notifyOfAddedX methods to MetricReporter interface
• links to: GitHub Pull Request #5501
• links to: GitHub Pull Request #5501