geode-core/src/main/java/org/apache/geode/internal/statistics/LocalStatListener.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.geode.internal.statistics;

/**
 * Implement this interface to receive call back when a stat value has changed. The listener has to
 * be registered with statSampler. This can be done in the following manner:
 *
 * <pre>
 * InternalDistributedSystem internalSystem = (InternalDistributedSystem) cache
 *     .getStatisticsManagerDistributedSystem();
 * final GemFireStatSampler sampler = internalSystem.getStatSampler();
 * sampler.addLocalStatListener(l, stats, statName);
 * </pre>
 *
 *
 */
public interface LocalStatListener {
  /**
   * Invoked when the value of a statistic has changed
   *
   * @param value The new value of the statistic
   */
  void statValueChanged(double value);
}