001/*
002 * JPPF.
003 * Copyright (C) 2005-2019 JPPF Team.
004 * http://www.jppf.org
005 *
006 * Licensed under the Apache License, Version 2.0 (the "License");
007 * you may not use this file except in compliance with the License.
008 * You may obtain a copy of the License at
009 *
010 *   http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019package org.jppf.utils.stats;
020
021/**
022 * A statistics listener with an optionally associated {@link JPPFStatistics.Filter snapshot filter}.
023 * @author Laurent Cohen
024 */
025public abstract class JPPFFilteredStatisticsListener implements JPPFStatisticsListener {
026  /**
027   * Get an optional filter to associate with this listener. The listener will only be notified for snapshots that are accepted by the filter.
028   * The default implementation returns {@code null} (no filter) and is intended to be overriden as needed in subclasses. 
029   * <p>Additionally, this method is only called once for each listener, so you don't have to keep a reference to the created filter.
030   * @return a {@link JPPFStatistics.Filter} instance.
031   */
032  public JPPFStatistics.Filter getFilter() {
033    return null;
034  }
035}