org.apache.zookeeper.metrics.Counter Maven / Gradle / Ivy
/*
* 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.zookeeper.metrics;
/**
* A counter refers to a value which can only increase.
* Usually the value is reset when the process starts.
*/
public interface Counter {
/**
* Increment the value by one.
* This method is thread safe, The MetricsProvider will take care of synchronization.
*/
default void inc() {
add(1);
}
/**
* Increment the value by a given amount.
* This method is thread safe, The MetricsProvider will take care of synchronization.
*
* @param delta amount to increment, this cannot be a negative number.
*/
void add(long delta);
/**
* Get the current value held by the counter.
* This method is thread safe, The MetricsProvider will take care of synchronization.
*
* @return the current value
*/
long get();
}