Java tutorial
/* * Copyright (c) 2012, 2019, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ /* * 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. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * * Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * * Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * * Neither the name of JSR-310 nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ package java.time; import static java.time.LocalTime.NANOS_PER_SECOND; import static java.time.LocalTime.SECONDS_PER_DAY; import static java.time.LocalTime.SECONDS_PER_HOUR; import static java.time.LocalTime.SECONDS_PER_MINUTE; import static java.time.temporal.ChronoField.INSTANT_SECONDS; import static java.time.temporal.ChronoField.MICRO_OF_SECOND; import static java.time.temporal.ChronoField.MILLI_OF_SECOND; import static java.time.temporal.ChronoField.NANO_OF_SECOND; import static java.time.temporal.ChronoUnit.DAYS; import static java.time.temporal.ChronoUnit.NANOS; import java.io.DataInput; import java.io.DataOutput; import java.io.IOException; import java.io.InvalidObjectException; import java.io.ObjectInputStream; import java.io.Serializable; import java.time.format.DateTimeFormatter; import java.time.format.DateTimeParseException; import java.time.temporal.ChronoField; import java.time.temporal.ChronoUnit; import java.time.temporal.Temporal; import java.time.temporal.TemporalAccessor; import java.time.temporal.TemporalAdjuster; import java.time.temporal.TemporalAmount; import java.time.temporal.TemporalField; import java.time.temporal.TemporalQueries; import java.time.temporal.TemporalQuery; import java.time.temporal.TemporalUnit; import java.time.temporal.UnsupportedTemporalTypeException; import java.time.temporal.ValueRange; import java.util.Objects; /** * An instantaneous point on the time-line. * <p> * This class models a single instantaneous point on the time-line. * This might be used to record event time-stamps in the application. * <p> * The range of an instant requires the storage of a number larger than a {@code long}. * To achieve this, the class stores a {@code long} representing epoch-seconds and an * {@code int} representing nanosecond-of-second, which will always be between 0 and 999,999,999. * The epoch-seconds are measured from the standard Java epoch of {@code 1970-01-01T00:00:00Z} * where instants after the epoch have positive values, and earlier instants have negative values. * For both the epoch-second and nanosecond parts, a larger value is always later on the time-line * than a smaller value. * * <h2>Time-scale</h2> * <p> * The length of the solar day is the standard way that humans measure time. * This has traditionally been subdivided into 24 hours of 60 minutes of 60 seconds, * forming a 86400 second day. * <p> * Modern timekeeping is based on atomic clocks which precisely define an SI second * relative to the transitions of a Caesium atom. The length of an SI second was defined * to be very close to the 86400th fraction of a day. * <p> * Unfortunately, as the Earth rotates the length of the day varies. * In addition, over time the average length of the day is getting longer as the Earth slows. * As a result, the length of a solar day in 2012 is slightly longer than 86400 SI seconds. * The actual length of any given day and the amount by which the Earth is slowing * are not predictable and can only be determined by measurement. * The UT1 time-scale captures the accurate length of day, but is only available some * time after the day has completed. * <p> * The UTC time-scale is a standard approach to bundle up all the additional fractions * of a second from UT1 into whole seconds, known as <i>leap-seconds</i>. * A leap-second may be added or removed depending on the Earth's rotational changes. * As such, UTC permits a day to have 86399 SI seconds or 86401 SI seconds where * necessary in order to keep the day aligned with the Sun. * <p> * The modern UTC time-scale was introduced in 1972, introducing the concept of whole leap-seconds. * Between 1958 and 1972, the definition of UTC was complex, with minor sub-second leaps and * alterations to the length of the notional second. As of 2012, discussions are underway * to change the definition of UTC again, with the potential to remove leap seconds or * introduce other changes. * <p> * Given the complexity of accurate timekeeping described above, this Java API defines * its own time-scale, the <i>Java Time-Scale</i>. * <p> * The Java Time-Scale divides each calendar day into exactly 86400 * subdivisions, known as seconds. These seconds may differ from the * SI second. It closely matches the de facto international civil time * scale, the definition of which changes from time to time. * <p> * The Java Time-Scale has slightly different definitions for different * segments of the time-line, each based on the consensus international * time scale that is used as the basis for civil time. Whenever the * internationally-agreed time scale is modified or replaced, a new * segment of the Java Time-Scale must be defined for it. Each segment * must meet these requirements: * <ul> * <li>the Java Time-Scale shall closely match the underlying international * civil time scale;</li> * <li>the Java Time-Scale shall exactly match the international civil * time scale at noon each day;</li> * <li>the Java Time-Scale shall have a precisely-defined relationship to * the international civil time scale.</li> * </ul> * There are currently, as of 2013, two segments in the Java time-scale. * <p> * For the segment from 1972-11-03 (exact boundary discussed below) until * further notice, the consensus international time scale is UTC (with * leap seconds). In this segment, the Java Time-Scale is identical to * <a href="http://www.cl.cam.ac.uk/~mgk25/time/utc-sls/">UTC-SLS</a>. * This is identical to UTC on days that do not have a leap second. * On days that do have a leap second, the leap second is spread equally * over the last 1000 seconds of the day, maintaining the appearance of * exactly 86400 seconds per day. * <p> * For the segment prior to 1972-11-03, extending back arbitrarily far, * the consensus international time scale is defined to be UT1, applied * proleptically, which is equivalent to the (mean) solar time on the * prime meridian (Greenwich). In this segment, the Java Time-Scale is * identical to the consensus international time scale. The exact * boundary between the two segments is the instant where UT1 = UTC * between 1972-11-03T00:00 and 1972-11-04T12:00. * <p> * Implementations of the Java time-scale using the JSR-310 API are not * required to provide any clock that is sub-second accurate, or that * progresses monotonically or smoothly. Implementations are therefore * not required to actually perform the UTC-SLS slew or to otherwise be * aware of leap seconds. JSR-310 does, however, require that * implementations must document the approach they use when defining a * clock representing the current instant. * See {@link Clock} for details on the available clocks. * <p> * The Java time-scale is used for all date-time classes. * This includes {@code Instant}, {@code LocalDate}, {@code LocalTime}, {@code OffsetDateTime}, * {@code ZonedDateTime} and {@code Duration}. * * <p> * This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a> * class; use of identity-sensitive operations (including reference equality * ({@code ==}), identity hash code, or synchronization) on instances of * {@code Instant} may have unpredictable results and should be avoided. * The {@code equals} method should be used for comparisons. * * @implSpec * This class is immutable and thread-safe. * * @since 1.8 */ public final class Instant implements Temporal, TemporalAdjuster, Comparable<Instant>, Serializable { /** * Constant for the 1970-01-01T00:00:00Z epoch instant. */ public static final Instant EPOCH = new Instant(0, 0); /** * The minimum supported epoch second. */ private static final long MIN_SECOND = -31557014167219200L; /** * The maximum supported epoch second. */ private static final long MAX_SECOND = 31556889864403199L; /** * The minimum supported {@code Instant}, '-1000000000-01-01T00:00Z'. * This could be used by an application as a "far past" instant. * <p> * This is one year earlier than the minimum {@code LocalDateTime}. * This provides sufficient values to handle the range of {@code ZoneOffset} * which affect the instant in addition to the local date-time. * The value is also chosen such that the value of the year fits in * an {@code int}. */ public static final Instant MIN = Instant.ofEpochSecond(MIN_SECOND, 0); /** * The maximum supported {@code Instant}, '1000000000-12-31T23:59:59.999999999Z'. * This could be used by an application as a "far future" instant. * <p> * This is one year later than the maximum {@code LocalDateTime}. * This provides sufficient values to handle the range of {@code ZoneOffset} * which affect the instant in addition to the local date-time. * The value is also chosen such that the value of the year fits in * an {@code int}. */ public static final Instant MAX = Instant.ofEpochSecond(MAX_SECOND, 999_999_999); /** * Serialization version. */ private static final long serialVersionUID = -665713676816604388L; /** * The number of seconds from the epoch of 1970-01-01T00:00:00Z. */ private final long seconds; /** * The number of nanoseconds, later along the time-line, from the seconds field. * This is always positive, and never exceeds 999,999,999. */ private final int nanos; //----------------------------------------------------------------------- /** * Obtains the current instant from the system clock. * <p> * This will query the {@link Clock#systemUTC() system UTC clock} to * obtain the current instant. * <p> * Using this method will prevent the ability to use an alternate time-source for * testing because the clock is effectively hard-coded. * * @return the current instant using the system clock, not null */ public static Instant now() { return Clock.systemUTC().instant(); } /** * Obtains the current instant from the specified clock. * <p> * This will query the specified clock to obtain the current time. * <p> * Using this method allows the use of an alternate clock for testing. * The alternate clock may be introduced using {@link Clock dependency injection}. * * @param clock the clock to use, not null * @return the current instant, not null */ public static Instant now(Clock clock) { Objects.requireNonNull(clock, "clock"); return clock.instant(); } //----------------------------------------------------------------------- /** * Obtains an instance of {@code Instant} using seconds from the * epoch of 1970-01-01T00:00:00Z. * <p> * The nanosecond field is set to zero. * * @param epochSecond the number of seconds from 1970-01-01T00:00:00Z * @return an instant, not null * @throws DateTimeException if the instant exceeds the maximum or minimum instant */ public static Instant ofEpochSecond(long epochSecond) { return create(epochSecond, 0); } /** * Obtains an instance of {@code Instant} using seconds from the * epoch of 1970-01-01T00:00:00Z and nanosecond fraction of second. * <p> * This method allows an arbitrary number of nanoseconds to be passed in. * The factory will alter the values of the second and nanosecond in order * to ensure that the stored nanosecond is in the range 0 to 999,999,999. * For example, the following will result in exactly the same instant: * <pre> * Instant.ofEpochSecond(3, 1); * Instant.ofEpochSecond(4, -999_999_999); * Instant.ofEpochSecond(2, 1000_000_001); * </pre> * * @param epochSecond the number of seconds from 1970-01-01T00:00:00Z * @param nanoAdjustment the nanosecond adjustment to the number of seconds, positive or negative * @return an instant, not null * @throws DateTimeException if the instant exceeds the maximum or minimum instant * @throws ArithmeticException if numeric overflow occurs */ public static Instant ofEpochSecond(long epochSecond, long nanoAdjustment) { long secs = Math.addExact(epochSecond, Math.floorDiv(nanoAdjustment, NANOS_PER_SECOND)); int nos = (int) Math.floorMod(nanoAdjustment, NANOS_PER_SECOND); return create(secs, nos); } /** * Obtains an instance of {@code Instant} using milliseconds from the * epoch of 1970-01-01T00:00:00Z. * <p> * The seconds and nanoseconds are extracted from the specified milliseconds. * * @param epochMilli the number of milliseconds from 1970-01-01T00:00:00Z * @return an instant, not null * @throws DateTimeException if the instant exceeds the maximum or minimum instant */ public static Instant ofEpochMilli(long epochMilli) { long secs = Math.floorDiv(epochMilli, 1000); int mos = Math.floorMod(epochMilli, 1000); return create(secs, mos * 1000_000); } //----------------------------------------------------------------------- /** * Obtains an instance of {@code Instant} from a temporal object. * <p> * This obtains an instant based on the specified temporal. * A {@code TemporalAccessor} represents an arbitrary set of date and time information, * which this factory converts to an instance of {@code Instant}. * <p> * The conversion extracts the {@link ChronoField#INSTANT_SECONDS INSTANT_SECONDS} * and {@link ChronoField#NANO_OF_SECOND NANO_OF_SECOND} fields. * <p> * This method matches the signature of the functional interface {@link TemporalQuery} * allowing it to be used as a query via method reference, {@code Instant::from}. * * @param temporal the temporal object to convert, not null * @return the instant, not null * @throws DateTimeException if unable to convert to an {@code Instant} */ public static Instant from(TemporalAccessor temporal) { if (temporal instanceof Instant) { return (Instant) temporal; } Objects.requireNonNull(temporal, "temporal"); try { long instantSecs = temporal.getLong(INSTANT_SECONDS); int nanoOfSecond = temporal.get(NANO_OF_SECOND); return Instant.ofEpochSecond(instantSecs, nanoOfSecond); } catch (DateTimeException ex) { throw new DateTimeException("Unable to obtain Instant from TemporalAccessor: " + temporal + " of type " + temporal.getClass().getName(), ex); } } //----------------------------------------------------------------------- /** * Obtains an instance of {@code Instant} from a text string such as * {@code 2007-12-03T10:15:30.00Z}. * <p> * The string must represent a valid instant in UTC and is parsed using * {@link DateTimeFormatter#ISO_INSTANT}. * * @param text the text to parse, not null * @return the parsed instant, not null * @throws DateTimeParseException if the text cannot be parsed */ public static Instant parse(final CharSequence text) { return DateTimeFormatter.ISO_INSTANT.parse(text, Instant::from); } //----------------------------------------------------------------------- /** * Obtains an instance of {@code Instant} using seconds and nanoseconds. * * @param seconds the length of the duration in seconds * @param nanoOfSecond the nano-of-second, from 0 to 999,999,999 * @throws DateTimeException if the instant exceeds the maximum or minimum instant */ private static Instant create(long seconds, int nanoOfSecond) { if ((seconds | nanoOfSecond) == 0) { return EPOCH; } if (seconds < MIN_SECOND || seconds > MAX_SECOND) { throw new DateTimeException("Instant exceeds minimum or maximum instant"); } return new Instant(seconds, nanoOfSecond); } /** * Constructs an instance of {@code Instant} using seconds from the epoch of * 1970-01-01T00:00:00Z and nanosecond fraction of second. * * @param epochSecond the number of seconds from 1970-01-01T00:00:00Z * @param nanos the nanoseconds within the second, must be positive */ private Instant(long epochSecond, int nanos) { super(); this.seconds = epochSecond; this.nanos = nanos; } //----------------------------------------------------------------------- /** * Checks if the specified field is supported. * <p> * This checks if this instant can be queried for the specified field. * If false, then calling the {@link #range(TemporalField) range}, * {@link #get(TemporalField) get} and {@link #with(TemporalField, long)} * methods will throw an exception. * <p> * If the field is a {@link ChronoField} then the query is implemented here. * The supported fields are: * <ul> * <li>{@code NANO_OF_SECOND} * <li>{@code MICRO_OF_SECOND} * <li>{@code MILLI_OF_SECOND} * <li>{@code INSTANT_SECONDS} * </ul> * All other {@code ChronoField} instances will return false. * <p> * If the field is not a {@code ChronoField}, then the result of this method * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)} * passing {@code this} as the argument. * Whether the field is supported is determined by the field. * * @param field the field to check, null returns false * @return true if the field is supported on this instant, false if not */ @Override public boolean isSupported(TemporalField field) { if (field instanceof ChronoField) { return field == INSTANT_SECONDS || field == NANO_OF_SECOND || field == MICRO_OF_SECOND || field == MILLI_OF_SECOND; } return field != null && field.isSupportedBy(this); } /** * Checks if the specified unit is supported. * <p> * This checks if the specified unit can be added to, or subtracted from, this date-time. * If false, then calling the {@link #plus(long, TemporalUnit)} and * {@link #minus(long, TemporalUnit) minus} methods will throw an exception. * <p> * If the unit is a {@link ChronoUnit} then the query is implemented here. * The supported units are: * <ul> * <li>{@code NANOS} * <li>{@code MICROS} * <li>{@code MILLIS} * <li>{@code SECONDS} * <li>{@code MINUTES} * <li>{@code HOURS} * <li>{@code HALF_DAYS} * <li>{@code DAYS} * </ul> * All other {@code ChronoUnit} instances will return false. * <p> * If the unit is not a {@code ChronoUnit}, then the result of this method * is obtained by invoking {@code TemporalUnit.isSupportedBy(Temporal)} * passing {@code this} as the argument. * Whether the unit is supported is determined by the unit. * * @param unit the unit to check, null returns false * @return true if the unit can be added/subtracted, false if not */ @Override public boolean isSupported(TemporalUnit unit) { if (unit instanceof ChronoUnit) { return unit.isTimeBased() || unit == DAYS; } return unit != null && unit.isSupportedBy(this); } //----------------------------------------------------------------------- /** * Gets the range of valid values for the specified field. * <p> * The range object expresses the minimum and maximum valid values for a field. * This instant is used to enhance the accuracy of the returned range. * If it is not possible to return the range, because the field is not supported * or for some other reason, an exception is thrown. * <p> * If the field is a {@link ChronoField} then the query is implemented here. * The {@link #isSupported(TemporalField) supported fields} will return * appropriate range instances. * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. * <p> * If the field is not a {@code ChronoField}, then the result of this method * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)} * passing {@code this} as the argument. * Whether the range can be obtained is determined by the field. * * @param field the field to query the range for, not null * @return the range of valid values for the field, not null * @throws DateTimeException if the range for the field cannot be obtained * @throws UnsupportedTemporalTypeException if the field is not supported */ @Override // override for Javadoc public ValueRange range(TemporalField field) { return Temporal.super.range(field); } /** * Gets the value of the specified field from this instant as an {@code int}. * <p> * This queries this instant for the value of the specified field. * The returned value will always be within the valid range of values for the field. * If it is not possible to return the value, because the field is not supported * or for some other reason, an exception is thrown. * <p> * If the field is a {@link ChronoField} then the query is implemented here. * The {@link #isSupported(TemporalField) supported fields} will return valid * values based on this date-time, except {@code INSTANT_SECONDS} which is too * large to fit in an {@code int} and throws a {@code DateTimeException}. * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. * <p> * If the field is not a {@code ChronoField}, then the result of this method * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)} * passing {@code this} as the argument. Whether the value can be obtained, * and what the value represents, is determined by the field. * * @param field the field to get, not null * @return the value for the field * @throws DateTimeException if a value for the field cannot be obtained or * the value is outside the range of valid values for the field * @throws UnsupportedTemporalTypeException if the field is not supported or * the range of values exceeds an {@code int} * @throws ArithmeticException if numeric overflow occurs */ @Override // override for Javadoc and performance public int get(TemporalField field) { if (field instanceof ChronoField) { switch ((ChronoField) field) { case NANO_OF_SECOND: return nanos; case MICRO_OF_SECOND: return nanos / 1000; case MILLI_OF_SECOND: return nanos / 1000_000; } throw new UnsupportedTemporalTypeException("Unsupported field: " + field); } return range(field).checkValidIntValue(field.getFrom(this), field); } /** * Gets the value of the specified field from this instant as a {@code long}. * <p> * This queries this instant for the value of the specified field. * If it is not possible to return the value, because the field is not supported * or for some other reason, an exception is thrown. * <p> * If the field is a {@link ChronoField} then the query is implemented here. * The {@link #isSupported(TemporalField) supported fields} will return valid * values based on this date-time. * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. * <p> * If the field is not a {@code ChronoField}, then the result of this method * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)} * passing {@code this} as the argument. Whether the value can be obtained, * and what the value represents, is determined by the field. * * @param field the field to get, not null * @return the value for the field * @throws DateTimeException if a value for the field cannot be obtained * @throws UnsupportedTemporalTypeException if the field is not supported * @throws ArithmeticException if numeric overflow occurs */ @Override public long getLong(TemporalField field) { if (field instanceof ChronoField) { switch ((ChronoField) field) { case NANO_OF_SECOND: return nanos; case MICRO_OF_SECOND: return nanos / 1000; case MILLI_OF_SECOND: return nanos / 1000_000; case INSTANT_SECONDS: return seconds; } throw new UnsupportedTemporalTypeException("Unsupported field: " + field); } return field.getFrom(this); } //----------------------------------------------------------------------- /** * Gets the number of seconds from the Java epoch of 1970-01-01T00:00:00Z. * <p> * The epoch second count is a simple incrementing count of seconds where * second 0 is 1970-01-01T00:00:00Z. * The nanosecond part is returned by {@link #getNano}. * * @return the seconds from the epoch of 1970-01-01T00:00:00Z */ public long getEpochSecond() { return seconds; } /** * Gets the number of nanoseconds, later along the time-line, from the start * of the second. * <p> * The nanosecond-of-second value measures the total number of nanoseconds from * the second returned by {@link #getEpochSecond}. * * @return the nanoseconds within the second, always positive, never exceeds 999,999,999 */ public int getNano() { return nanos; } //------------------------------------------------------------------------- /** * Returns an adjusted copy of this instant. * <p> * This returns an {@code Instant}, based on this one, with the instant adjusted. * The adjustment takes place using the specified adjuster strategy object. * Read the documentation of the adjuster to understand what adjustment will be made. * <p> * The result of this method is obtained by invoking the * {@link TemporalAdjuster#adjustInto(Temporal)} method on the * specified adjuster passing {@code this} as the argument. * <p> * This instance is immutable and unaffected by this method call. * * @param adjuster the adjuster to use, not null * @return an {@code Instant} based on {@code this} with the adjustment made, not null * @throws DateTimeException if the adjustment cannot be made * @throws ArithmeticException if numeric overflow occurs */ @Override public Instant with(TemporalAdjuster adjuster) { return (Instant) adjuster.adjustInto(this); } /** * Returns a copy of this instant with the specified field set to a new value. * <p> * This returns an {@code Instant}, based on this one, with the value * for the specified field changed. * If it is not possible to set the value, because the field is not supported or for * some other reason, an exception is thrown. * <p> * If the field is a {@link ChronoField} then the adjustment is implemented here. * The supported fields behave as follows: * <ul> * <li>{@code NANO_OF_SECOND} - * Returns an {@code Instant} with the specified nano-of-second. * The epoch-second will be unchanged. * <li>{@code MICRO_OF_SECOND} - * Returns an {@code Instant} with the nano-of-second replaced by the specified * micro-of-second multiplied by 1,000. The epoch-second will be unchanged. * <li>{@code MILLI_OF_SECOND} - * Returns an {@code Instant} with the nano-of-second replaced by the specified * milli-of-second multiplied by 1,000,000. The epoch-second will be unchanged. * <li>{@code INSTANT_SECONDS} - * Returns an {@code Instant} with the specified epoch-second. * The nano-of-second will be unchanged. * </ul> * <p> * In all cases, if the new value is outside the valid range of values for the field * then a {@code DateTimeException} will be thrown. * <p> * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. * <p> * If the field is not a {@code ChronoField}, then the result of this method * is obtained by invoking {@code TemporalField.adjustInto(Temporal, long)} * passing {@code this} as the argument. In this case, the field determines * whether and how to adjust the instant. * <p> * This instance is immutable and unaffected by this method call. * * @param field the field to set in the result, not null * @param newValue the new value of the field in the result * @return an {@code Instant} based on {@code this} with the specified field set, not null * @throws DateTimeException if the field cannot be set * @throws UnsupportedTemporalTypeException if the field is not supported * @throws ArithmeticException if numeric overflow occurs */ @Override public Instant with(TemporalField field, long newValue) { if (field instanceof ChronoField) { ChronoField f = (ChronoField) field; f.checkValidValue(newValue); switch (f) { case MILLI_OF_SECOND: { int nval = (int) newValue * 1000_000; return (nval != nanos ? create(seconds, nval) : this); } case MICRO_OF_SECOND: { int nval = (int) newValue * 1000; return (nval != nanos ? create(seconds, nval) : this); } case NANO_OF_SECOND: return (newValue != nanos ? create(seconds, (int) newValue) : this); case INSTANT_SECONDS: return (newValue != seconds ? create(newValue, nanos) : this); } throw new UnsupportedTemporalTypeException("Unsupported field: " + field); } return field.adjustInto(this, newValue); } //----------------------------------------------------------------------- /** * Returns a copy of this {@code Instant} truncated to the specified unit. * <p> * Truncating the instant returns a copy of the original with fields * smaller than the specified unit set to zero. * The fields are calculated on the basis of using a UTC offset as seen * in {@code toString}. * For example, truncating with the {@link ChronoUnit#MINUTES MINUTES} unit will * round down to the nearest minute, setting the seconds and nanoseconds to zero. * <p> * The unit must have a {@linkplain TemporalUnit#getDuration() duration} * that divides into the length of a standard day without remainder. * This includes all supplied time units on {@link ChronoUnit} and * {@link ChronoUnit#DAYS DAYS}. Other units throw an exception. * <p> * This instance is immutable and unaffected by this method call. * * @param unit the unit to truncate to, not null * @return an {@code Instant} based on this instant with the time truncated, not null * @throws DateTimeException if the unit is invalid for truncation * @throws UnsupportedTemporalTypeException if the unit is not supported */ public Instant truncatedTo(TemporalUnit unit) { if (unit == ChronoUnit.NANOS) { return this; } Duration unitDur = unit.getDuration(); if (unitDur.getSeconds() > LocalTime.SECONDS_PER_DAY) { throw new UnsupportedTemporalTypeException("Unit is too large to be used for truncation"); } long dur = unitDur.toNanos(); if ((LocalTime.NANOS_PER_DAY % dur) != 0) { throw new UnsupportedTemporalTypeException("Unit must divide into a standard day without remainder"); } long nod = (seconds % LocalTime.SECONDS_PER_DAY) * LocalTime.NANOS_PER_SECOND + nanos; long result = Math.floorDiv(nod, dur) * dur; return plusNanos(result - nod); } //----------------------------------------------------------------------- /** * Returns a copy of this instant with the specified amount added. * <p> * This returns an {@code Instant}, based on this one, with the specified amount added. * The amount is typically {@link Duration} but may be any other type implementing * the {@link TemporalAmount} interface. * <p> * The calculation is delegated to the amount object by calling * {@link TemporalAmount#addTo(Temporal)}. The amount implementation is free * to implement the addition in any way it wishes, however it typically * calls back to {@link #plus(long, TemporalUnit)}. Consult the documentation * of the amount implementation to determine if it can be successfully added. * <p> * This instance is immutable and unaffected by this method call. * * @param amountToAdd the amount to add, not null * @return an {@code Instant} based on this instant with the addition made, not null * @throws DateTimeException if the addition cannot be made * @throws ArithmeticException if numeric overflow occurs */ @Override public Instant plus(TemporalAmount amountToAdd) { return (Instant) amountToAdd.addTo(this); } /** * Returns a copy of this instant with the specified amount added. * <p> * This returns an {@code Instant}, based on this one, with the amount * in terms of the unit added. If it is not possible to add the amount, because the * unit is not supported or for some other reason, an exception is thrown. * <p> * If the field is a {@link ChronoUnit} then the addition is implemented here. * The supported fields behave as follows: * <ul> * <li>{@code NANOS} - * Returns an {@code Instant} with the specified number of nanoseconds added. * This is equivalent to {@link #plusNanos(long)}. * <li>{@code MICROS} - * Returns an {@code Instant} with the specified number of microseconds added. * This is equivalent to {@link #plusNanos(long)} with the amount * multiplied by 1,000. * <li>{@code MILLIS} - * Returns an {@code Instant} with the specified number of milliseconds added. * This is equivalent to {@link #plusNanos(long)} with the amount * multiplied by 1,000,000. * <li>{@code SECONDS} - * Returns an {@code Instant} with the specified number of seconds added. * This is equivalent to {@link #plusSeconds(long)}. * <li>{@code MINUTES} - * Returns an {@code Instant} with the specified number of minutes added. * This is equivalent to {@link #plusSeconds(long)} with the amount * multiplied by 60. * <li>{@code HOURS} - * Returns an {@code Instant} with the specified number of hours added. * This is equivalent to {@link #plusSeconds(long)} with the amount * multiplied by 3,600. * <li>{@code HALF_DAYS} - * Returns an {@code Instant} with the specified number of half-days added. * This is equivalent to {@link #plusSeconds(long)} with the amount * multiplied by 43,200 (12 hours). * <li>{@code DAYS} - * Returns an {@code Instant} with the specified number of days added. * This is equivalent to {@link #plusSeconds(long)} with the amount * multiplied by 86,400 (24 hours). * </ul> * <p> * All other {@code ChronoUnit} instances will throw an {@code UnsupportedTemporalTypeException}. * <p> * If the field is not a {@code ChronoUnit}, then the result of this method * is obtained by invoking {@code TemporalUnit.addTo(Temporal, long)} * passing {@code this} as the argument. In this case, the unit determines * whether and how to perform the addition. * <p> * This instance is immutable and unaffected by this method call. * * @param amountToAdd the amount of the unit to add to the result, may be negative * @param unit the unit of the amount to add, not null * @return an {@code Instant} based on this instant with the specified amount added, not null * @throws DateTimeException if the addition cannot be made * @throws UnsupportedTemporalTypeException if the unit is not supported * @throws ArithmeticException if numeric overflow occurs */ @Override public Instant plus(long amountToAdd, TemporalUnit unit) { if (unit instanceof ChronoUnit) { switch ((ChronoUnit) unit) { case NANOS: return plusNanos(amountToAdd); case MICROS: return plus(amountToAdd / 1000_000, (amountToAdd % 1000_000) * 1000); case MILLIS: return plusMillis(amountToAdd); case SECONDS: return plusSeconds(amountToAdd); case MINUTES: return plusSeconds(Math.multiplyExact(amountToAdd, SECONDS_PER_MINUTE)); case HOURS: return plusSeconds(Math.multiplyExact(amountToAdd, SECONDS_PER_HOUR)); case HALF_DAYS: return plusSeconds(Math.multiplyExact(amountToAdd, SECONDS_PER_DAY / 2)); case DAYS: return plusSeconds(Math.multiplyExact(amountToAdd, SECONDS_PER_DAY)); } throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit); } return unit.addTo(this, amountToAdd); } //----------------------------------------------------------------------- /** * Returns a copy of this instant with the specified duration in seconds added. * <p> * This instance is immutable and unaffected by this method call. * * @param secondsToAdd the seconds to add, positive or negative * @return an {@code Instant} based on this instant with the specified seconds added, not null * @throws DateTimeException if the result exceeds the maximum or minimum instant * @throws ArithmeticException if numeric overflow occurs */ public Instant plusSeconds(long secondsToAdd) { return plus(secondsToAdd, 0); } /** * Returns a copy of this instant with the specified duration in milliseconds added. * <p> * This instance is immutable and unaffected by this method call. * * @param millisToAdd the milliseconds to add, positive or negative * @return an {@code Instant} based on this instant with the specified milliseconds added, not null * @throws DateTimeException if the result exceeds the maximum or minimum instant * @throws ArithmeticException if numeric overflow occurs */ public Instant plusMillis(long millisToAdd) { return plus(millisToAdd / 1000, (millisToAdd % 1000) * 1000_000); } /** * Returns a copy of this instant with the specified duration in nanoseconds added. * <p> * This instance is immutable and unaffected by this method call. * * @param nanosToAdd the nanoseconds to add, positive or negative * @return an {@code Instant} based on this instant with the specified nanoseconds added, not null * @throws DateTimeException if the result exceeds the maximum or minimum instant * @throws ArithmeticException if numeric overflow occurs */ public Instant plusNanos(long nanosToAdd) { return plus(0, nanosToAdd); } /** * Returns a copy of this instant with the specified duration added. * <p> * This instance is immutable and unaffected by this method call. * * @param secondsToAdd the seconds to add, positive or negative * @param nanosToAdd the nanos to add, positive or negative * @return an {@code Instant} based on this instant with the specified seconds added, not null * @throws DateTimeException if the result exceeds the maximum or minimum instant * @throws ArithmeticException if numeric overflow occurs */ private Instant plus(long secondsToAdd, long nanosToAdd) { if ((secondsToAdd | nanosToAdd) == 0) { return this; } long epochSec = Math.addExact(seconds, secondsToAdd); epochSec = Math.addExact(epochSec, nanosToAdd / NANOS_PER_SECOND); nanosToAdd = nanosToAdd % NANOS_PER_SECOND; long nanoAdjustment = nanos + nanosToAdd; // safe int+NANOS_PER_SECOND return ofEpochSecond(epochSec, nanoAdjustment); } //----------------------------------------------------------------------- /** * Returns a copy of this instant with the specified amount subtracted. * <p> * This returns an {@code Instant}, based on this one, with the specified amount subtracted. * The amount is typically {@link Duration} but may be any other type implementing * the {@link TemporalAmount} interface. * <p> * The calculation is delegated to the amount object by calling * {@link TemporalAmount#subtractFrom(Temporal)}. The amount implementation is free * to implement the subtraction in any way it wishes, however it typically * calls back to {@link #minus(long, TemporalUnit)}. Consult the documentation * of the amount implementation to determine if it can be successfully subtracted. * <p> * This instance is immutable and unaffected by this method call. * * @param amountToSubtract the amount to subtract, not null * @return an {@code Instant} based on this instant with the subtraction made, not null * @throws DateTimeException if the subtraction cannot be made * @throws ArithmeticException if numeric overflow occurs */ @Override public Instant minus(TemporalAmount amountToSubtract) { return (Instant) amountToSubtract.subtractFrom(this); } /** * Returns a copy of this instant with the specified amount subtracted. * <p> * This returns an {@code Instant}, based on this one, with the amount * in terms of the unit subtracted. If it is not possible to subtract the amount, * because the unit is not supported or for some other reason, an exception is thrown. * <p> * This method is equivalent to {@link #plus(long, TemporalUnit)} with the amount negated. * See that method for a full description of how addition, and thus subtraction, works. * <p> * This instance is immutable and unaffected by this method call. * * @param amountToSubtract the amount of the unit to subtract from the result, may be negative * @param unit the unit of the amount to subtract, not null * @return an {@code Instant} based on this instant with the specified amount subtracted, not null * @throws DateTimeException if the subtraction cannot be made * @throws UnsupportedTemporalTypeException if the unit is not supported * @throws ArithmeticException if numeric overflow occurs */ @Override public Instant minus(long amountToSubtract, TemporalUnit unit) { return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit)); } //----------------------------------------------------------------------- /** * Returns a copy of this instant with the specified duration in seconds subtracted. * <p> * This instance is immutable and unaffected by this method call. * * @param secondsToSubtract the seconds to subtract, positive or negative * @return an {@code Instant} based on this instant with the specified seconds subtracted, not null * @throws DateTimeException if the result exceeds the maximum or minimum instant * @throws ArithmeticException if numeric overflow occurs */ public Instant minusSeconds(long secondsToSubtract) { if (secondsToSubtract == Long.MIN_VALUE) { return plusSeconds(Long.MAX_VALUE).plusSeconds(1); } return plusSeconds(-secondsToSubtract); } /** * Returns a copy of this instant with the specified duration in milliseconds subtracted. * <p> * This instance is immutable and unaffected by this method call. * * @param millisToSubtract the milliseconds to subtract, positive or negative * @return an {@code Instant} based on this instant with the specified milliseconds subtracted, not null * @throws DateTimeException if the result exceeds the maximum or minimum instant * @throws ArithmeticException if numeric overflow occurs */ public Instant minusMillis(long millisToSubtract) { if (millisToSubtract == Long.MIN_VALUE) { return plusMillis(Long.MAX_VALUE).plusMillis(1); } return plusMillis(-millisToSubtract); } /** * Returns a copy of this instant with the specified duration in nanoseconds subtracted. * <p> * This instance is immutable and unaffected by this method call. * * @param nanosToSubtract the nanoseconds to subtract, positive or negative * @return an {@code Instant} based on this instant with the specified nanoseconds subtracted, not null * @throws DateTimeException if the result exceeds the maximum or minimum instant * @throws ArithmeticException if numeric overflow occurs */ public Instant minusNanos(long nanosToSubtract) { if (nanosToSubtract == Long.MIN_VALUE) { return plusNanos(Long.MAX_VALUE).plusNanos(1); } return plusNanos(-nanosToSubtract); } //------------------------------------------------------------------------- /** * Queries this instant using the specified query. * <p> * This queries this instant using the specified query strategy object. * The {@code TemporalQuery} object defines the logic to be used to * obtain the result. Read the documentation of the query to understand * what the result of this method will be. * <p> * The result of this method is obtained by invoking the * {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the * specified query passing {@code this} as the argument. * * @param <R> the type of the result * @param query the query to invoke, not null * @return the query result, null may be returned (defined by the query) * @throws DateTimeException if unable to query (defined by the query) * @throws ArithmeticException if numeric overflow occurs (defined by the query) */ @SuppressWarnings("unchecked") @Override public <R> R query(TemporalQuery<R> query) { if (query == TemporalQueries.precision()) { return (R) NANOS; } // inline TemporalAccessor.super.query(query) as an optimization if (query == TemporalQueries.chronology() || query == TemporalQueries.zoneId() || query == TemporalQueries.zone() || query == TemporalQueries.offset() || query == TemporalQueries.localDate() || query == TemporalQueries.localTime()) { return null; } return query.queryFrom(this); } /** * Adjusts the specified temporal object to have this instant. * <p> * This returns a temporal object of the same observable type as the input * with the instant changed to be the same as this. * <p> * The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)} * twice, passing {@link ChronoField#INSTANT_SECONDS} and * {@link ChronoField#NANO_OF_SECOND} as the fields. * <p> * In most cases, it is clearer to reverse the calling pattern by using * {@link Temporal#with(TemporalAdjuster)}: * <pre> * // these two lines are equivalent, but the second approach is recommended * temporal = thisInstant.adjustInto(temporal); * temporal = temporal.with(thisInstant); * </pre> * <p> * This instance is immutable and unaffected by this method call. * * @param temporal the target object to be adjusted, not null * @return the adjusted object, not null * @throws DateTimeException if unable to make the adjustment * @throws ArithmeticException if numeric overflow occurs */ @Override public Temporal adjustInto(Temporal temporal) { return temporal.with(INSTANT_SECONDS, seconds).with(NANO_OF_SECOND, nanos); } /** * Calculates the amount of time until another instant in terms of the specified unit. * <p> * This calculates the amount of time between two {@code Instant} * objects in terms of a single {@code TemporalUnit}. * The start and end points are {@code this} and the specified instant. * The result will be negative if the end is before the start. * The calculation returns a whole number, representing the number of * complete units between the two instants. * The {@code Temporal} passed to this method is converted to a * {@code Instant} using {@link #from(TemporalAccessor)}. * For example, the amount in seconds between two dates can be calculated * using {@code startInstant.until(endInstant, SECONDS)}. * <p> * There are two equivalent ways of using this method. * The first is to invoke this method. * The second is to use {@link TemporalUnit#between(Temporal, Temporal)}: * <pre> * // these two lines are equivalent * amount = start.until(end, SECONDS); * amount = SECONDS.between(start, end); * </pre> * The choice should be made based on which makes the code more readable. * <p> * The calculation is implemented in this method for {@link ChronoUnit}. * The units {@code NANOS}, {@code MICROS}, {@code MILLIS}, {@code SECONDS}, * {@code MINUTES}, {@code HOURS}, {@code HALF_DAYS} and {@code DAYS} * are supported. Other {@code ChronoUnit} values will throw an exception. * <p> * If the unit is not a {@code ChronoUnit}, then the result of this method * is obtained by invoking {@code TemporalUnit.between(Temporal, Temporal)} * passing {@code this} as the first argument and the converted input temporal * as the second argument. * <p> * This instance is immutable and unaffected by this method call. * * @param endExclusive the end date, exclusive, which is converted to an {@code Instant}, not null * @param unit the unit to measure the amount in, not null * @return the amount of time between this instant and the end instant * @throws DateTimeException if the amount cannot be calculated, or the end * temporal cannot be converted to an {@code Instant} * @throws UnsupportedTemporalTypeException if the unit is not supported * @throws ArithmeticException if numeric overflow occurs */ @Override public long until(Temporal endExclusive, TemporalUnit unit) { Instant end = Instant.from(endExclusive); if (unit instanceof ChronoUnit) { ChronoUnit f = (ChronoUnit) unit; switch (f) { case NANOS: return nanosUntil(end); case MICROS: return nanosUntil(end) / 1000; case MILLIS: return Math.subtractExact(end.toEpochMilli(), toEpochMilli()); case SECONDS: return secondsUntil(end); case MINUTES: return secondsUntil(end) / SECONDS_PER_MINUTE; case HOURS: return secondsUntil(end) / SECONDS_PER_HOUR; case HALF_DAYS: return secondsUntil(end) / (12 * SECONDS_PER_HOUR); case DAYS: return secondsUntil(end) / (SECONDS_PER_DAY); } throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit); } return unit.between(this, end); } private long nanosUntil(Instant end) { long secsDiff = Math.subtractExact(end.seconds, seconds); long totalNanos = Math.multiplyExact(secsDiff, NANOS_PER_SECOND); return Math.addExact(totalNanos, end.nanos - nanos); } private long secondsUntil(Instant end) { long secsDiff = Math.subtractExact(end.seconds, seconds); long nanosDiff = end.nanos - nanos; if (secsDiff > 0 && nanosDiff < 0) { secsDiff--; } else if (secsDiff < 0 && nanosDiff > 0) { secsDiff++; } return secsDiff; } //----------------------------------------------------------------------- /** * Combines this instant with an offset to create an {@code OffsetDateTime}. * <p> * This returns an {@code OffsetDateTime} formed from this instant at the * specified offset from UTC/Greenwich. An exception will be thrown if the * instant is too large to fit into an offset date-time. * <p> * This method is equivalent to * {@link OffsetDateTime#ofInstant(Instant, ZoneId) OffsetDateTime.ofInstant(this, offset)}. * * @param offset the offset to combine with, not null * @return the offset date-time formed from this instant and the specified offset, not null * @throws DateTimeException if the result exceeds the supported range */ public OffsetDateTime atOffset(ZoneOffset offset) { return OffsetDateTime.ofInstant(this, offset); } /** * Combines this instant with a time-zone to create a {@code ZonedDateTime}. * <p> * This returns an {@code ZonedDateTime} formed from this instant at the * specified time-zone. An exception will be thrown if the instant is too * large to fit into a zoned date-time. * <p> * This method is equivalent to * {@link ZonedDateTime#ofInstant(Instant, ZoneId) ZonedDateTime.ofInstant(this, zone)}. * * @param zone the zone to combine with, not null * @return the zoned date-time formed from this instant and the specified zone, not null * @throws DateTimeException if the result exceeds the supported range */ public ZonedDateTime atZone(ZoneId zone) { return ZonedDateTime.ofInstant(this, zone); } //----------------------------------------------------------------------- /** * Converts this instant to the number of milliseconds from the epoch * of 1970-01-01T00:00:00Z. * <p> * If this instant represents a point on the time-line too far in the future * or past to fit in a {@code long} milliseconds, then an exception is thrown. * <p> * If this instant has greater than millisecond precision, then the conversion * will drop any excess precision information as though the amount in nanoseconds * was subject to integer division by one million. * * @return the number of milliseconds since the epoch of 1970-01-01T00:00:00Z * @throws ArithmeticException if numeric overflow occurs */ public long toEpochMilli() { if (seconds < 0 && nanos > 0) { long millis = Math.multiplyExact(seconds + 1, 1000); long adjustment = nanos / 1000_000 - 1000; return Math.addExact(millis, adjustment); } else { long millis = Math.multiplyExact(seconds, 1000); return Math.addExact(millis, nanos / 1000_000); } } //----------------------------------------------------------------------- /** * Compares this instant to the specified instant. * <p> * The comparison is based on the time-line position of the instants. * It is "consistent with equals", as defined by {@link Comparable}. * * @param otherInstant the other instant to compare to, not null * @return the comparator value, negative if less, positive if greater * @throws NullPointerException if otherInstant is null */ @Override public int compareTo(Instant otherInstant) { int cmp = Long.compare(seconds, otherInstant.seconds); if (cmp != 0) { return cmp; } return nanos - otherInstant.nanos; } /** * Checks if this instant is after the specified instant. * <p> * The comparison is based on the time-line position of the instants. * * @param otherInstant the other instant to compare to, not null * @return true if this instant is after the specified instant * @throws NullPointerException if otherInstant is null */ public boolean isAfter(Instant otherInstant) { return compareTo(otherInstant) > 0; } /** * Checks if this instant is before the specified instant. * <p> * The comparison is based on the time-line position of the instants. * * @param otherInstant the other instant to compare to, not null * @return true if this instant is before the specified instant * @throws NullPointerException if otherInstant is null */ public boolean isBefore(Instant otherInstant) { return compareTo(otherInstant) < 0; } //----------------------------------------------------------------------- /** * Checks if this instant is equal to the specified instant. * <p> * The comparison is based on the time-line position of the instants. * * @param otherInstant the other instant, null returns false * @return true if the other instant is equal to this one */ @Override public boolean equals(Object otherInstant) { if (this == otherInstant) { return true; } if (otherInstant instanceof Instant) { Instant other = (Instant) otherInstant; return this.seconds == other.seconds && this.nanos == other.nanos; } return false; } /** * Returns a hash code for this instant. * * @return a suitable hash code */ @Override public int hashCode() { return ((int) (seconds ^ (seconds >>> 32))) + 51 * nanos; } //----------------------------------------------------------------------- /** * A string representation of this instant using ISO-8601 representation. * <p> * The format used is the same as {@link DateTimeFormatter#ISO_INSTANT}. * * @return an ISO-8601 representation of this instant, not null */ @Override public String toString() { return DateTimeFormatter.ISO_INSTANT.format(this); } // ----------------------------------------------------------------------- /** * Writes the object using a * <a href="{@docRoot}/serialized-form.html#java.time.Ser">dedicated serialized form</a>. * @serialData * <pre> * out.writeByte(2); // identifies an Instant * out.writeLong(seconds); * out.writeInt(nanos); * </pre> * * @return the instance of {@code Ser}, not null */ private Object writeReplace() { return new Ser(Ser.INSTANT_TYPE, this); } /** * Defend against malicious streams. * * @param s the stream to read * @throws InvalidObjectException always */ private void readObject(ObjectInputStream s) throws InvalidObjectException { throw new InvalidObjectException("Deserialization via serialization delegate"); } void writeExternal(DataOutput out) throws IOException { out.writeLong(seconds); out.writeInt(nanos); } static Instant readExternal(DataInput in) throws IOException { long seconds = in.readLong(); int nanos = in.readInt(); return Instant.ofEpochSecond(seconds, nanos); } }