1 /*
2 * Copyright (c) 2001-2017, Zoltan Farkas All Rights Reserved.
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Additionally licensed with:
19 *
20 * Licensed under the Apache License, Version 2.0 (the "License");
21 * you may not use this file except in compliance with the License.
22 * You may obtain a copy of the License at
23 *
24 * http://www.apache.org/licenses/LICENSE-2.0
25 *
26 * Unless required by applicable law or agreed to in writing, software
27 * distributed under the License is distributed on an "AS IS" BASIS,
28 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
29 * See the License for the specific language governing permissions and
30 * limitations under the License.
31 */
32 package org.spf4j.base;
33
34 import com.google.common.annotations.Beta;
35 import java.time.Instant;
36 import java.util.concurrent.TimeUnit;
37
38 /**
39 * A Utility class that allows for quick conversion between nanotime and epoch relative time.
40 * @author Zoltan Farkas
41 */
42 @Beta
43 public final class Timing {
44
45 public static final long MAX_MS_SPAN = TimeUnit.NANOSECONDS.toMillis(Long.MAX_VALUE);
46
47 static {
48 // load classes to improve timing.
49 TimeSource.nanoTime();
50 System.currentTimeMillis();
51 }
52
53 private static final Timing LATEST_TIMING = new Timing();
54
55 private final long nanoTimeRef;
56 private final long currentTimeMillisRef;
57
58 private Timing() {
59 nanoTimeRef = TimeSource.nanoTime();
60 currentTimeMillisRef = System.currentTimeMillis();
61 }
62
63 public long fromNanoTimeToEpochMillis(final long nanoTime) {
64 return currentTimeMillisRef + TimeUnit.NANOSECONDS.toMillis(nanoTime - nanoTimeRef);
65 }
66
67 public Instant fromNanoTimeToInstant(final long nanoTime) {
68 long relNanos = nanoTime - nanoTimeRef;
69 return Instant.ofEpochSecond(currentTimeMillisRef / 1000
70 + relNanos / 1000000000, (currentTimeMillisRef % 1000) * 1000000 + relNanos % 1000000000);
71 }
72
73 public long fromEpochMillisToNanoTime(final long epochTimeMillis) {
74 long msSinceLast = epochTimeMillis - currentTimeMillisRef;
75 if (Math.abs(msSinceLast) > MAX_MS_SPAN) {
76 return TimeSource.nanoTime() + Long.MAX_VALUE;
77 }
78 return nanoTimeRef + TimeUnit.MILLISECONDS.toNanos(msSinceLast);
79 }
80
81 public static Timing getCurrentTiming() {
82 return LATEST_TIMING;
83 }
84
85 @Override
86 public String toString() {
87 return "Timing{" + "nanoTimeRef=" + nanoTimeRef + ", currentTimeMillisRef=" + currentTimeMillisRef + '}';
88 }
89
90
91 }