001/* 002 * Copyright (C) 2008 The Guava Authors 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package com.google.common.testing; 018 019import static com.google.common.base.Preconditions.checkArgument; 020 021import com.google.common.annotations.Beta; 022import com.google.common.annotations.GwtCompatible; 023import com.google.common.base.Ticker; 024import java.util.concurrent.TimeUnit; 025import java.util.concurrent.atomic.AtomicLong; 026 027/** 028 * A Ticker whose value can be advanced programmatically in test. 029 * 030 * <p>The ticker can be configured so that the time is incremented whenever {@link #read} is called: 031 * see {@link #setAutoIncrementStep}. 032 * 033 * <p>This class is thread-safe. 034 * 035 * @author Jige Yu 036 * @since 10.0 037 */ 038@Beta 039@GwtCompatible 040public class FakeTicker extends Ticker { 041 042 private final AtomicLong nanos = new AtomicLong(); 043 private volatile long autoIncrementStepNanos; 044 045 /** Advances the ticker value by {@code time} in {@code timeUnit}. */ 046 public FakeTicker advance(long time, TimeUnit timeUnit) { 047 return advance(timeUnit.toNanos(time)); 048 } 049 050 /** Advances the ticker value by {@code nanoseconds}. */ 051 public FakeTicker advance(long nanoseconds) { 052 nanos.addAndGet(nanoseconds); 053 return this; 054 } 055 056 /** 057 * Sets the increment applied to the ticker whenever it is queried. 058 * 059 * <p>The default behavior is to auto increment by zero. i.e: The ticker is left unchanged when 060 * queried. 061 */ 062 public FakeTicker setAutoIncrementStep(long autoIncrementStep, TimeUnit timeUnit) { 063 checkArgument(autoIncrementStep >= 0, "May not auto-increment by a negative amount"); 064 this.autoIncrementStepNanos = timeUnit.toNanos(autoIncrementStep); 065 return this; 066 } 067 068 @Override 069 public long read() { 070 return nanos.getAndAdd(autoIncrementStepNanos); 071 } 072}