2 * Copyright (c) 2014 Brocade Communications Systems, Inc. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.yangtools.util;
10 import static java.util.concurrent.TimeUnit.MICROSECONDS;
11 import static java.util.concurrent.TimeUnit.MILLISECONDS;
12 import static java.util.concurrent.TimeUnit.NANOSECONDS;
13 import static java.util.concurrent.TimeUnit.SECONDS;
14 import com.google.common.annotations.Beta;
15 import java.text.DecimalFormat;
16 import java.text.DecimalFormatSymbols;
17 import java.util.Date;
18 import java.util.concurrent.TimeUnit;
19 import org.slf4j.Logger;
20 import org.slf4j.LoggerFactory;
23 * Abstract class that calculates and tracks time duration statistics.
25 * @author Thomas Pantelis
26 * @author Robert Varga
29 public abstract class DurationStatisticsTracker {
30 private static final Logger LOG = LoggerFactory.getLogger(DurationStatisticsTracker.class);
31 private static final DecimalFormat DECIMAL_FORMAT;
34 final DecimalFormatSymbols symbols = DecimalFormatSymbols.getInstance();
35 symbols.setDecimalSeparator('.');
36 DECIMAL_FORMAT = new DecimalFormat("0.00", symbols);
40 * Create a concurrent {@link DurationStatisticsTracker}, which performs well
41 * in very contended environments.
43 * @return A new instance.
45 public static DurationStatisticsTracker createConcurrent() {
46 return new ConcurrentDurationStatisticsTracker();
50 * Create a synchronized {@link DurationStatisticsTracker}, which performs well
51 * in non-contended environments.
53 * @return A new instance.
55 public static DurationStatisticsTracker createSynchronized() {
56 return new SynchronizedDurationStatsTracker();
60 * Add a duration to track.
63 * non-negative duration in nanoseconds.
65 public abstract void addDuration(long duration);
68 * Returns the average duration in nanoseconds.
70 public abstract double getAverageDuration();
73 * Returns the total number of tracked durations.
75 * @return Total number of measurements accumulated since last
78 public abstract long getTotalDurations();
81 * Resets all statistics back to their defaults.
83 public abstract void reset();
86 * Get the shortest recorded duration and the time when it was recorded.
88 * @return Duration and timestamp.
90 protected abstract DurationWithTime getShortest();
93 * Get the longest recorded duration and the time when it was recorded.
95 * @return Duration and timestamp.
97 protected abstract DurationWithTime getLongest();
100 * Returns the longest duration in nanoseconds.
102 public final long getLongestDuration() {
103 return getDuration(getLongest());
107 * Returns the shortest duration in nanoseconds.
109 public final long getShortestDuration() {
110 return getDuration(getShortest());
114 * Returns the average duration as a displayable String with units, e.g.
117 public final String getDisplayableAverageDuration() {
118 return formatDuration(getAverageDuration(), null);
122 * Returns the longest duration as a displayable String with units and the
123 * date/time at which it occurred, e.g. "12.34 ms at 08/02/2014 12:30:24".
125 public final String getDisplayableLongestDuration() {
126 return formatDuration(getLongest());
130 * Returns the shortest duration as a displayable String with units and the
131 * date/time at which it occurred, e.g. "12.34 ms at 08/02/2014 12:30:24".
133 public final String getDisplayableShortestDuration() {
134 return formatDuration(getShortest());
138 * Returns the time stamp of the longest duration.
140 public final long getTimeOfLongestDuration() {
141 return getTimeMillis(getLongest());
145 * Returns the time stamp of the shortest duration.
147 public final long getTimeOfShortestDuration() {
148 return getTimeMillis(getShortest());
152 * Returns formatted value of number, e.g. "12.34". Always is used dot as
155 private static synchronized String formatDecimalValue(final double value) {
156 return DECIMAL_FORMAT.format(value);
159 private static long getDuration(final DurationWithTime current) {
160 return current == null ? 0L : current.getDuration();
163 private static long getTimeMillis(final DurationWithTime current) {
164 return current == null ? 0L : current.getTimeMillis();
167 private static String formatDuration(final double duration, final Long timeStamp) {
168 final TimeUnit unit = chooseUnit((long) duration);
169 final double value = duration / NANOSECONDS.convert(1, unit);
171 final StringBuilder sb = new StringBuilder();
172 sb.append(formatDecimalValue(value));
174 sb.append(abbreviate(unit));
176 if (timeStamp != null) {
177 sb.append(String.format(" at %1$tD %1$tT", new Date(timeStamp)));
180 return sb.toString();
183 private static String formatDuration(final DurationWithTime current) {
184 if (current != null) {
185 return formatDuration(current.getDuration(), current.getTimeMillis());
187 return formatDuration(0, null);
191 private static TimeUnit chooseUnit(final long nanos) {
192 // TODO: this could be inlined, as we are doing needless divisions
193 if (NANOSECONDS.toSeconds(nanos) > 0) {
196 if (NANOSECONDS.toMillis(nanos) > 0) {
199 if (NANOSECONDS.toMicros(nanos) > 0) {
205 private static String abbreviate(final TimeUnit unit) {
210 return "\u03bcs"; // μs
223 LOG.warn("Unhandled time unit {}", unit);