001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache license, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the license for the specific language governing permissions and 015 * limitations under the license. 016 */ 017 018package org.apache.logging.log4j.core.util; 019 020import java.util.Objects; 021 022/** 023 * Creates the appropriate {@link NanoClock} instance for the current configuration. 024 */ 025public class NanoClockFactory { 026 027 /** 028 * Enum over the different kinds of nano clocks this factory can create. 029 */ 030 public static enum Mode { 031 /** 032 * Creates dummy nano clocks that always return a fixed value. 033 */ 034 Dummy { 035 @Override 036 public NanoClock createNanoClock() { 037 return new DummyNanoClock(); 038 } 039 }, 040 /** 041 * Creates real nano clocks which call {{System.nanoTime()}}. 042 */ 043 System { 044 @Override 045 public NanoClock createNanoClock() { 046 return new SystemNanoClock(); 047 } 048 }, 049 ; 050 051 public abstract NanoClock createNanoClock(); 052 } 053 054 private static volatile Mode mode = Mode.Dummy; 055 056 /** 057 * Returns a new {@code NanoClock} determined by the mode of this factory. 058 * 059 * @return the appropriate {@code NanoClock} for the factory mode 060 */ 061 public static NanoClock createNanoClock() { 062 return mode.createNanoClock(); 063 } 064 065 /** 066 * Returns the factory mode. 067 * 068 * @return the factory mode that determines which kind of nano clocks this factory creates 069 */ 070 public static Mode getMode() { 071 return mode; 072 } 073 074 /** 075 * Sets the factory mode. 076 * 077 * @param mode the factory mode that determines which kind of nano clocks this factory creates 078 */ 079 public static void setMode(Mode mode) { 080 NanoClockFactory.mode = Objects.requireNonNull(mode, "mode must be non-null"); 081 } 082}