zookeeper-server/src/main/java/org/apache/zookeeper/metrics/Gauge.java

/*
 * 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 Gauge is an application provided object which will be called by the framework in order to sample the value
 * of an integer value.
 */
public interface Gauge {

    /**
     * Returns the current value associated with this gauge.
     * The MetricsProvider will call this callback without taking care of synchronization, it is up to the application
     * to handle thread safety.
     *
     * @return the current value for the gauge
     */
    Number get();

}