Source code

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.appender.rolling.action;
019
020import java.io.Serializable;
021import java.util.Objects;
022import java.util.regex.Matcher;
023import java.util.regex.Pattern;
024
025/**
026 * Simplified implementation of the <a href="https://en.wikipedia.org/wiki/ISO_8601#Durations">ISO-8601 Durations</a>
027 * standard. The supported format is {@code PnDTnHnMnS}, with 'P' and 'T' optional. Days are considered to be exactly 24
028 * hours.
029 * <p>
030 * Similarly to the {@code java.time.Duration} class, this class does not support year or month sections in the format.
031 * This implementation does not support fractions or negative values.
032 *
033 * @see #parse(CharSequence)
034 */
035public class Duration implements Serializable, Comparable<Duration> {
036    private static final long serialVersionUID = -3756810052716342061L;
037
038    /**
039     * Constant for a duration of zero.
040     */
041    public static final Duration ZERO = new Duration(0);
042
043    /**
044     * Hours per day.
045     */
046    private static final int HOURS_PER_DAY = 24;
047    /**
048     * Minutes per hour.
049     */
050    private static final int MINUTES_PER_HOUR = 60;
051    /**
052     * Seconds per minute.
053     */
054    private static final int SECONDS_PER_MINUTE = 60;
055    /**
056     * Seconds per hour.
057     */
058    private static final int SECONDS_PER_HOUR = SECONDS_PER_MINUTE * MINUTES_PER_HOUR;
059    /**
060     * Seconds per day.
061     */
062    private static final int SECONDS_PER_DAY = SECONDS_PER_HOUR * HOURS_PER_DAY;
063
064    /**
065     * The pattern for parsing.
066     */
067    private static final Pattern PATTERN = Pattern.compile("P?(?:([0-9]+)D)?"
068            + "(T?(?:([0-9]+)H)?(?:([0-9]+)M)?(?:([0-9]+)?S)?)?", Pattern.CASE_INSENSITIVE);
069
070    /**
071     * The number of seconds in the duration.
072     */
073    private final long seconds;
074
075    /**
076     * Constructs an instance of {@code Duration} using seconds.
077     *
078     * @param seconds the length of the duration in seconds, positive or negative
079     */
080    private Duration(final long seconds) {
081        this.seconds = seconds;
082    }
083
084    /**
085     * Obtains a {@code Duration} from a text string such as {@code PnDTnHnMnS}.
086     * <p>
087     * This will parse a textual representation of a duration, including the string produced by {@code toString()}. The
088     * formats accepted are based on the ISO-8601 duration format {@code PnDTnHnMnS} with days considered to be exactly
089     * 24 hours.
090     * <p>
091     * This implementation does not support negative numbers or fractions (so the smallest non-zero value a Duration can
092     * have is one second).
093     * <p>
094     * The string optionally starts with the ASCII letter "P" in upper or lower case. There are then four sections, each
095     * consisting of a number and a suffix. The sections have suffixes in ASCII of "D", "H", "M" and "S" for days,
096     * hours, minutes and seconds, accepted in upper or lower case. The suffixes must occur in order. The ASCII letter
097     * "T" may occur before the first occurrence, if any, of an hour, minute or second section. At least one of the four
098     * sections must be present, and if "T" is present there must be at least one section after the "T". The number part
099     * of each section must consist of one or more ASCII digits. The number may not be prefixed by the ASCII negative or
100     * positive symbol. The number of days, hours, minutes and seconds must parse to a {@code long}.
101     * <p>
102     * Examples:
103     *
104     * <pre>
105     *    "PT20S" -- parses as "20 seconds"
106     *    "PT15M"     -- parses as "15 minutes" (where a minute is 60 seconds)
107     *    "PT10H"     -- parses as "10 hours" (where an hour is 3600 seconds)
108     *    "P2D"       -- parses as "2 days" (where a day is 24 hours or 86400 seconds)
109     *    "P2DT3H4M"  -- parses as "2 days, 3 hours and 4 minutes"
110     * </pre>
111     *
112     * @param text the text to parse, not null
113     * @return the parsed duration, not null
114     * @throws IllegalArgumentException if the text cannot be parsed to a duration
115     */
116    public static Duration parse(final CharSequence text) {
117        Objects.requireNonNull(text, "text");
118        final Matcher matcher = PATTERN.matcher(text);
119        if (matcher.matches()) {
120            // check for letter T but no time sections
121            if ("T".equals(matcher.group(2)) == false) {
122                final String dayMatch = matcher.group(1);
123                final String hourMatch = matcher.group(3);
124                final String minuteMatch = matcher.group(4);
125                final String secondMatch = matcher.group(5);
126                if (dayMatch != null || hourMatch != null || minuteMatch != null || secondMatch != null) {
127                    final long daysAsSecs = parseNumber(text, dayMatch, SECONDS_PER_DAY, "days");
128                    final long hoursAsSecs = parseNumber(text, hourMatch, SECONDS_PER_HOUR, "hours");
129                    final long minsAsSecs = parseNumber(text, minuteMatch, SECONDS_PER_MINUTE, "minutes");
130                    final long seconds = parseNumber(text, secondMatch, 1, "seconds");
131                    try {
132                        return create(daysAsSecs, hoursAsSecs, minsAsSecs, seconds);
133                    } catch (final ArithmeticException ex) {
134                        throw new IllegalArgumentException("Text cannot be parsed to a Duration (overflow) " + text, ex);
135                    }
136                }
137            }
138        }
139        throw new IllegalArgumentException("Text cannot be parsed to a Duration: " + text);
140    }
141
142    private static long parseNumber(final CharSequence text, final String parsed, final int multiplier,
143            final String errorText) {
144        // regex limits to [0-9]+
145        if (parsed == null) {
146            return 0;
147        }
148        try {
149            final long val = Long.parseLong(parsed);
150            return val * multiplier;
151        } catch (final Exception ex) {
152            throw new IllegalArgumentException("Text cannot be parsed to a Duration: " + errorText + " (in " + text
153                    + ")", ex);
154        }
155    }
156
157    private static Duration create(final long daysAsSecs, final long hoursAsSecs, final long minsAsSecs, final long secs) {
158        return create(daysAsSecs + hoursAsSecs + minsAsSecs + secs);
159    }
160
161    /**
162     * Obtains an instance of {@code Duration} using seconds.
163     *
164     * @param seconds the length of the duration in seconds, positive only
165     */
166    private static Duration create(final long seconds) {
167        if ((seconds) == 0) {
168            return ZERO;
169        }
170        return new Duration(seconds);
171    }
172
173    /**
174     * Converts this duration to the total length in milliseconds.
175     *
176     * @return the total length of the duration in milliseconds
177     */
178    public long toMillis() {
179        return seconds * 1000L;
180    }
181
182    @Override
183    public boolean equals(final Object obj) {
184        if (obj == this) {
185            return true;
186        }
187        if (!(obj instanceof Duration)) {
188            return false;
189        }
190        final Duration other = (Duration) obj;
191        return other.seconds == this.seconds;
192    }
193
194    @Override
195    public int hashCode() {
196        return (int) (seconds ^ (seconds >>> 32));
197    }
198
199    /**
200     * A string representation of this duration using ISO-8601 seconds based representation, such as {@code PT8H6M12S}.
201     * <p>
202     * The format of the returned string will be {@code PnDTnHnMnS}, where n is the relevant days, hours, minutes or
203     * seconds part of the duration. If a section has a zero value, it is omitted. The hours, minutes and seconds are
204     * all positive.
205     * <p>
206     * Examples:
207     *
208     * <pre>
209     *    "20 seconds"                     -- "PT20S
210     *    "15 minutes" (15 * 60 seconds)   -- "PT15M"
211     *    "10 hours" (10 * 3600 seconds)   -- "PT10H"
212     *    "2 days" (2 * 86400 seconds)     -- "P2D"
213     * </pre>
214     *
215     * @return an ISO-8601 representation of this duration, not null
216     */
217    @Override
218    public String toString() {
219        if (this == ZERO) {
220            return "PT0S";
221        }
222        final long days = seconds / SECONDS_PER_DAY;
223        final long hours = (seconds % SECONDS_PER_DAY) / SECONDS_PER_HOUR;
224        final int minutes = (int) ((seconds % SECONDS_PER_HOUR) / SECONDS_PER_MINUTE);
225        final int secs = (int) (seconds % SECONDS_PER_MINUTE);
226        final StringBuilder buf = new StringBuilder(24);
227        buf.append("P");
228        if (days != 0) {
229            buf.append(days).append('D');
230        }
231        if ((hours | minutes | secs) != 0) {
232            buf.append('T');
233        }
234        if (hours != 0) {
235            buf.append(hours).append('H');
236        }
237        if (minutes != 0) {
238            buf.append(minutes).append('M');
239        }
240        if (secs == 0 && buf.length() > 0) {
241            return buf.toString();
242        }
243        buf.append(secs).append('S');
244        return buf.toString();
245    }
246
247    /*
248     * (non-Javadoc)
249     *
250     * @see java.lang.Comparable#compareTo(java.lang.Object)
251     */
252    @Override
253    public int compareTo(final Duration other) {
254        return Long.signum(toMillis() - other.toMillis());
255    }
256}