[GitHub] flink pull request #5501: [FLINK-6053][metrics] Add new Number-/StringGauge ...

[StephanEwen <gi...@git.apache.org>]

Github user StephanEwen commented on a diff in the pull request:

    https://github.com/apache/flink/pull/5501#discussion_r173146575
  
    --- Diff: flink-metrics/flink-metrics-core/src/main/java/org/apache/flink/metrics/NumberGauge.java ---
    @@ -0,0 +1,26 @@
    +/*
    + * Licensed to the Apache Software Foundation (ASF) under one
    + * or more contributor license agreements.  See the NOTICE file
    + * distributed with this work for additional information
    + * regarding copyright ownership.  The ASF licenses this file
    + * to you under the Apache License, Version 2.0 (the
    + * "License"); you may not use this file except in compliance
    + * with the License.  You may obtain a copy of the License at
    + *
    + *     http://www.apache.org/licenses/LICENSE-2.0
    + *
    + * Unless required by applicable law or agreed to in writing, software
    + * distributed under the License is distributed on an "AS IS" BASIS,
    + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    + * See the License for the specific language governing permissions and
    + * limitations under the License.
    + */
    +
    +package org.apache.flink.metrics;
    +
    +/**
    + * A NumberGauge is a {@link Metric} that calculates a specific {@link Number} value at a point in time.
    + */
    +public interface NumberGauge extends Metric {
    --- End diff --
    
    Should be annotated with `@FunctionalInterface` to guard that this always stays lambda-able.
    
    Also annotate with Public / PublicEvolving?


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