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/*
* This file is available under and governed by the GNU General Public
* License version 2 only, as published by the Free Software Foundation.
* However, the following notice accompanied the original version of this
* file:
*
* Copyright (c) 2007-2012, Stephen Colebourne & Michael Nascimento Santos
*
* All rights reserved.
*
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package build.tools.tzdb;
import java.util.Objects;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
/**
* A time-zone offset from Greenwich/UTC, such as {@code +02:00}.
* <p>
* A time-zone offset is the period of time that a time-zone differs from Greenwich/UTC.
* This is usually a fixed number of hours and minutes.
*
* @since 1.8
*/
final class ZoneOffset implements Comparable<ZoneOffset> {
/** Cache of time-zone offset by offset in seconds. */
private static final ConcurrentMap<Integer, ZoneOffset> SECONDS_CACHE = new ConcurrentHashMap<>(16, 0.75f, 4);
/** Cache of time-zone offset by ID. */
private static final ConcurrentMap<String, ZoneOffset> ID_CACHE = new ConcurrentHashMap<>(16, 0.75f, 4);
/**
* The number of seconds per hour.
*/
private static final int SECONDS_PER_HOUR = 60 * 60;
/**
* The number of seconds per minute.
*/
private static final int SECONDS_PER_MINUTE = 60;
/**
* The number of minutes per hour.
*/
private static final int MINUTES_PER_HOUR = 60;
/**
* The abs maximum seconds.
*/
private static final int MAX_SECONDS = 18 * SECONDS_PER_HOUR;
/**
* Serialization version.
*/
private static final long serialVersionUID = 2357656521762053153L;
/**
* The time-zone offset for UTC, with an ID of 'Z'.
*/
public static final ZoneOffset UTC = ZoneOffset.ofTotalSeconds(0);
/**
* Constant for the maximum supported offset.
*/
public static final ZoneOffset MIN = ZoneOffset.ofTotalSeconds(-MAX_SECONDS);
/**
* Constant for the maximum supported offset.
*/
public static final ZoneOffset MAX = ZoneOffset.ofTotalSeconds(MAX_SECONDS);
/**
* The total offset in seconds.
*/
private final int totalSeconds;
/**
* The string form of the time-zone offset.
*/
private final transient String id;
//-----------------------------------------------------------------------
/**
* Obtains an instance of {@code ZoneOffset} using the ID.
* <p>
* This method parses the string ID of a {@code ZoneOffset} to
* return an instance. The parsing accepts all the formats generated by
* {@link #getId()}, plus some additional formats:
* <p><ul>
* <li>{@code Z} - for UTC
* <li>{@code +h}
* <li>{@code +hh}
* <li>{@code +hh:mm}
* <li>{@code -hh:mm}
* <li>{@code +hhmm}
* <li>{@code -hhmm}
* <li>{@code +hh:mm:ss}
* <li>{@code -hh:mm:ss}
* <li>{@code +hhmmss}
* <li>{@code -hhmmss}
* </ul><p>
* Note that ± means either the plus or minus symbol.
* <p>
* The ID of the returned offset will be normalized to one of the formats
* described by {@link #getId()}.
* <p>
* The maximum supported range is from +18:00 to -18:00 inclusive.
*
* @param offsetId the offset ID, not null
* @return the zone-offset, not null
* @throws DateTimeException if the offset ID is invalid
*/
@SuppressWarnings("fallthrough")
public static ZoneOffset of(String offsetId) {
Objects.requireNonNull(offsetId, "offsetId");
// "Z" is always in the cache
ZoneOffset offset = ID_CACHE.get(offsetId);
if (offset != null) {
return offset;
}
// parse - +h, +hh, +hhmm, +hh:mm, +hhmmss, +hh:mm:ss
final int hours, minutes, seconds;
switch (offsetId.length()) {
case 2:
offsetId = offsetId.charAt(0) + "0" + offsetId.charAt(1); // fallthru
case 3:
hours = parseNumber(offsetId, 1, false);
minutes = 0;
seconds = 0;
break;
case 5:
hours = parseNumber(offsetId, 1, false);
minutes = parseNumber(offsetId, 3, false);
seconds = 0;
break;
case 6:
hours = parseNumber(offsetId, 1, false);
minutes = parseNumber(offsetId, 4, true);
seconds = 0;
break;
case 7:
hours = parseNumber(offsetId, 1, false);
minutes = parseNumber(offsetId, 3, false);
seconds = parseNumber(offsetId, 5, false);
break;
case 9:
hours = parseNumber(offsetId, 1, false);
minutes = parseNumber(offsetId, 4, true);
seconds = parseNumber(offsetId, 7, true);
break;
default:
throw new DateTimeException("Zone offset ID '" + offsetId + "' is invalid");
}
char first = offsetId.charAt(0);
if (first != '+' && first != '-') {
throw new DateTimeException("Zone offset ID '" + offsetId + "' is invalid: Plus/minus not found when expected");
}
if (first == '-') {
return ofHoursMinutesSeconds(-hours, -minutes, -seconds);
} else {
return ofHoursMinutesSeconds(hours, minutes, seconds);
}
}
/**
* Parse a two digit zero-prefixed number.
*
* @param offsetId the offset ID, not null
* @param pos the position to parse, valid
* @param precededByColon should this number be prefixed by a precededByColon
* @return the parsed number, from 0 to 99
*/
private static int parseNumber(CharSequence offsetId, int pos, boolean precededByColon) {
if (precededByColon && offsetId.charAt(pos - 1) != ':') {
throw new DateTimeException("Zone offset ID '" + offsetId + "' is invalid: Colon not found when expected");
}
char ch1 = offsetId.charAt(pos);
char ch2 = offsetId.charAt(pos + 1);
if (ch1 < '0' || ch1 > '9' || ch2 < '0' || ch2 > '9') {
throw new DateTimeException("Zone offset ID '" + offsetId + "' is invalid: Non numeric characters found");
}
return (ch1 - 48) * 10 + (ch2 - 48);
}
//-----------------------------------------------------------------------
/**
* Obtains an instance of {@code ZoneOffset} using an offset in hours.
*
* @param hours the time-zone offset in hours, from -18 to +18
* @return the zone-offset, not null
* @throws DateTimeException if the offset is not in the required range
*/
public static ZoneOffset ofHours(int hours) {
return ofHoursMinutesSeconds(hours, 0, 0);
}
/**
* Obtains an instance of {@code ZoneOffset} using an offset in
* hours and minutes.
* <p>
* The sign of the hours and minutes components must match.
* Thus, if the hours is negative, the minutes must be negative or zero.
* If the hours is zero, the minutes may be positive, negative or zero.
*
* @param hours the time-zone offset in hours, from -18 to +18
* @param minutes the time-zone offset in minutes, from 0 to ±59, sign matches hours
* @return the zone-offset, not null
* @throws DateTimeException if the offset is not in the required range
*/
public static ZoneOffset ofHoursMinutes(int hours, int minutes) {
return ofHoursMinutesSeconds(hours, minutes, 0);
}
/**
* Obtains an instance of {@code ZoneOffset} using an offset in
* hours, minutes and seconds.
* <p>
* The sign of the hours, minutes and seconds components must match.
* Thus, if the hours is negative, the minutes and seconds must be negative or zero.
*
* @param hours the time-zone offset in hours, from -18 to +18
* @param minutes the time-zone offset in minutes, from 0 to ±59, sign matches hours and seconds
* @param seconds the time-zone offset in seconds, from 0 to ±59, sign matches hours and minutes
* @return the zone-offset, not null
* @throws DateTimeException if the offset is not in the required range
*/
public static ZoneOffset ofHoursMinutesSeconds(int hours, int minutes, int seconds) {
validate(hours, minutes, seconds);
int totalSeconds = totalSeconds(hours, minutes, seconds);
return ofTotalSeconds(totalSeconds);
}
/**
* Validates the offset fields.
*
* @param hours the time-zone offset in hours, from -18 to +18
* @param minutes the time-zone offset in minutes, from 0 to ±59
* @param seconds the time-zone offset in seconds, from 0 to ±59
* @throws DateTimeException if the offset is not in the required range
*/
private static void validate(int hours, int minutes, int seconds) {
if (hours < -18 || hours > 18) {
throw new DateTimeException("Zone offset hours not in valid range: value " + hours +
" is not in the range -18 to 18");
}
if (hours > 0) {
if (minutes < 0 || seconds < 0) {
throw new DateTimeException("Zone offset minutes and seconds must be positive because hours is positive");
}
} else if (hours < 0) {
if (minutes > 0 || seconds > 0) {
throw new DateTimeException("Zone offset minutes and seconds must be negative because hours is negative");
}
} else if ((minutes > 0 && seconds < 0) || (minutes < 0 && seconds > 0)) {
throw new DateTimeException("Zone offset minutes and seconds must have the same sign");
}
if (Math.abs(minutes) > 59) {
throw new DateTimeException("Zone offset minutes not in valid range: abs(value) " +
Math.abs(minutes) + " is not in the range 0 to 59");
}
if (Math.abs(seconds) > 59) {
throw new DateTimeException("Zone offset seconds not in valid range: abs(value) " +
Math.abs(seconds) + " is not in the range 0 to 59");
}
if (Math.abs(hours) == 18 && (Math.abs(minutes) > 0 || Math.abs(seconds) > 0)) {
throw new DateTimeException("Zone offset not in valid range: -18:00 to +18:00");
}
}
/**
* Calculates the total offset in seconds.
*
* @param hours the time-zone offset in hours, from -18 to +18
* @param minutes the time-zone offset in minutes, from 0 to ±59, sign matches hours and seconds
* @param seconds the time-zone offset in seconds, from 0 to ±59, sign matches hours and minutes
* @return the total in seconds
*/
private static int totalSeconds(int hours, int minutes, int seconds) {
return hours * SECONDS_PER_HOUR + minutes * SECONDS_PER_MINUTE + seconds;
}
//-----------------------------------------------------------------------
/**
* Obtains an instance of {@code ZoneOffset} specifying the total offset in seconds
* <p>
* The offset must be in the range {@code -18:00} to {@code +18:00}, which corresponds to -64800 to +64800.
*
* @param totalSeconds the total time-zone offset in seconds, from -64800 to +64800
* @return the ZoneOffset, not null
* @throws DateTimeException if the offset is not in the required range
*/
public static ZoneOffset ofTotalSeconds(int totalSeconds) {
if (Math.abs(totalSeconds) > MAX_SECONDS) {
throw new DateTimeException("Zone offset not in valid range: -18:00 to +18:00");
}
if (totalSeconds % (15 * SECONDS_PER_MINUTE) == 0) {
Integer totalSecs = totalSeconds;
ZoneOffset result = SECONDS_CACHE.get(totalSecs);
if (result == null) {
result = new ZoneOffset(totalSeconds);
SECONDS_CACHE.putIfAbsent(totalSecs, result);
result = SECONDS_CACHE.get(totalSecs);
ID_CACHE.putIfAbsent(result.getId(), result);
}
return result;
} else {
return new ZoneOffset(totalSeconds);
}
}
/**
* Constructor.
*
* @param totalSeconds the total time-zone offset in seconds, from -64800 to +64800
*/
private ZoneOffset(int totalSeconds) {
super();
this.totalSeconds = totalSeconds;
id = buildId(totalSeconds);
}
private static String buildId(int totalSeconds) {
if (totalSeconds == 0) {
return "Z";
} else {
int absTotalSeconds = Math.abs(totalSeconds);
StringBuilder buf = new StringBuilder();
int absHours = absTotalSeconds / SECONDS_PER_HOUR;
int absMinutes = (absTotalSeconds / SECONDS_PER_MINUTE) % MINUTES_PER_HOUR;
buf.append(totalSeconds < 0 ? "-" : "+")
.append(absHours < 10 ? "0" : "").append(absHours)
.append(absMinutes < 10 ? ":0" : ":").append(absMinutes);
int absSeconds = absTotalSeconds % SECONDS_PER_MINUTE;
if (absSeconds != 0) {
buf.append(absSeconds < 10 ? ":0" : ":").append(absSeconds);
}
return buf.toString();
}
}
/**
* Gets the total zone offset in seconds.
* <p>
* This is the primary way to access the offset amount.
* It returns the total of the hours, minutes and seconds fields as a
* single offset that can be added to a time.
*
* @return the total zone offset amount in seconds
*/
public int getTotalSeconds() {
return totalSeconds;
}
/**
* Gets the normalized zone offset ID.
* <p>
* The ID is minor variation to the standard ISO-8601 formatted string
* for the offset. There are three formats:
* <p><ul>
* <li>{@code Z} - for UTC (ISO-8601)
* <li>{@code +hh:mm} or {@code -hh:mm} - if the seconds are zero (ISO-8601)
* <li>{@code +hh:mm:ss} or {@code -hh:mm:ss} - if the seconds are non-zero (not ISO-8601)
* </ul><p>
*
* @return the zone offset ID, not null
*/
public String getId() {
return id;
}
/**
* Compares this offset to another offset in descending order.
* <p>
* The offsets are compared in the order that they occur for the same time
* of day around the world. Thus, an offset of {@code +10:00} comes before an
* offset of {@code +09:00} and so on down to {@code -18:00}.
* <p>
* The comparison is "consistent with equals", as defined by {@link Comparable}.
*
* @param other the other date to compare to, not null
* @return the comparator value, negative if less, postive if greater
* @throws NullPointerException if {@code other} is null
*/
@Override
public int compareTo(ZoneOffset other) {
return other.totalSeconds - totalSeconds;
}
/**
* Checks if this offset is equal to another offset.
* <p>
* The comparison is based on the amount of the offset in seconds.
* This is equivalent to a comparison by ID.
*
* @param obj the object to check, null returns false
* @return true if this is equal to the other offset
*/
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj instanceof ZoneOffset) {
return totalSeconds == ((ZoneOffset) obj).totalSeconds;
}
return false;
}
/**
* A hash code for this offset.
*
* @return a suitable hash code
*/
@Override
public int hashCode() {
return totalSeconds;
}
/**
* Outputs this offset as a {@code String}, using the normalized ID.
*
* @return a string representation of this offset, not null
*/
@Override
public String toString() {
return id;
}
}