/*
* Copyright 2001-2010 Stephen Colebourne
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.joda.time;
import java.io.Serializable;
import org.joda.convert.FromString;
import org.joda.time.base.AbstractInstant;
import org.joda.time.chrono.ISOChronology;
import org.joda.time.convert.ConverterManager;
import org.joda.time.convert.InstantConverter;
import org.joda.time.format.DateTimeFormatter;
import org.joda.time.format.ISODateTimeFormat;
/**
* Instant is the standard implementation of a fully immutable instant in time.
* <p>
* <code>Instant</code> is an implementation of {@link ReadableInstant}.
* As with all instants, it represents an exact point on the time-line,
* but limited to the precision of milliseconds. An <code>Instant</code>
* should be used to represent a point in time irrespective of any other
* factor, such as chronology or time zone.
* <p>
* Internally, the class holds one piece of data, the instant as milliseconds
* from the Java epoch of 1970-01-01T00:00:00Z.
* <p>
* For example, an Instant can be used to compare two <code>DateTime</code>
* objects irrespective of chronology or time zone.
* <pre>
* boolean sameInstant = dt1.toInstant().equals(dt2.toInstant());
* </pre>
* Note that the following code will also perform the same check:
* <pre>
* boolean sameInstant = dt1.isEqual(dt2);
* </pre>
* <p>
* Instant is thread-safe and immutable.
*
* @author Stephen Colebourne
* @since 1.0
*/
public final class Instant
extends AbstractInstant
implements ReadableInstant, Serializable {
/** Serialization lock */
private static final long serialVersionUID = 3299096530934209741L;
/** The millis from 1970-01-01T00:00:00Z */
private final long iMillis;
//-----------------------------------------------------------------------
/**
* Obtains an {@code Instant} set to the current system millisecond time.
*
* @return the current instant, not null
* @since 2.0
*/
public static Instant now() {
return new Instant();
}
//-----------------------------------------------------------------------
/**
* Parses a {@code Instant} from the specified string.
* <p>
* This uses {@link ISODateTimeFormat#dateTimeParser()}.
*
* @param str the string to parse, not null
* @since 2.0
*/
@FromString
public static Instant parse(String str) {
return parse(str, ISODateTimeFormat.dateTimeParser());
}
/**
* Parses a {@code Instant} from the specified string using a formatter.
*
* @param str the string to parse, not null
* @param formatter the formatter to use, not null
* @since 2.0
*/
public static Instant parse(String str, DateTimeFormatter formatter) {
return formatter.parseDateTime(str).toInstant();
}
//-----------------------------------------------------------------------
/**
* Constructs an instance set to the current system millisecond time.
*
* @see #now()
*/
public Instant() {
super();
iMillis = DateTimeUtils.currentTimeMillis();
}
/**
* Constructs an instance set to the milliseconds from 1970-01-01T00:00:00Z.
*
* @param instant the milliseconds from 1970-01-01T00:00:00Z
*/
public Instant(long instant) {
super();
iMillis = instant;
}
/**
* Constructs an instance from an Object that represents a datetime.
* <p>
* The recognised object types are defined in {@link ConverterManager} and
* include String, Calendar and Date.
*
* @param instant the datetime object, null means now
* @throws IllegalArgumentException if the instant is invalid
*/
public Instant(Object instant) {
super();
InstantConverter converter = ConverterManager.getInstance().getInstantConverter(instant);
iMillis = converter.getInstantMillis(instant, ISOChronology.getInstanceUTC());
}
//-----------------------------------------------------------------------
/**
* Get this object as an Instant by returning <code>this</code>.
*
* @return <code>this</code>
*/
public Instant toInstant() {
return this;
}
//-----------------------------------------------------------------------
/**
* Gets a copy of this instant with different millis.
* <p>
* The returned object will be either be a new Instant or <code>this</code>.
*
* @param newMillis the new millis, from 1970-01-01T00:00:00Z
* @return a copy of this instant with different millis
*/
public Instant withMillis(long newMillis) {
return (newMillis == iMillis ? this : new Instant(newMillis));
}
/**
* Gets a copy of this instant with the specified duration added.
* <p>
* If the addition is zero, then <code>this</code> is returned.
*
* @param durationToAdd the duration to add to this one
* @param scalar the amount of times to add, such as -1 to subtract once
* @return a copy of this instant with the duration added
* @throws ArithmeticException if the new instant exceeds the capacity of a long
*/
public Instant withDurationAdded(long durationToAdd, int scalar) {
if (durationToAdd == 0 || scalar == 0) {
return this;
}
long instant = getChronology().add(getMillis(), durationToAdd, scalar);
return withMillis(instant);
}
/**
* Gets a copy of this instant with the specified duration added.
* <p>
* If the addition is zero, then <code>this</code> is returned.
*
* @param durationToAdd the duration to add to this one, null means zero
* @param scalar the amount of times to add, such as -1 to subtract once
* @return a copy of this instant with the duration added
* @throws ArithmeticException if the new instant exceeds the capacity of a long
*/
public Instant withDurationAdded(ReadableDuration durationToAdd, int scalar) {
if (durationToAdd == null || scalar == 0) {
return this;
}
return withDurationAdded(durationToAdd.getMillis(), scalar);
}
//-----------------------------------------------------------------------
/**
* Gets a copy of this instant with the specified duration added.
* <p>
* If the amount is zero or null, then <code>this</code> is returned.
*
* @param duration the duration to add to this one
* @return a copy of this instant with the duration added
* @throws ArithmeticException if the new instant exceeds the capacity of a long
*/
public Instant plus(long duration) {
return withDurationAdded(duration, 1);
}
/**
* Gets a copy of this instant with the specified duration added.
* <p>
* If the amount is zero or null, then <code>this</code> is returned.
*
* @param duration the duration to add to this one, null means zero
* @return a copy of this instant with the duration added
* @throws ArithmeticException if the new instant exceeds the capacity of a long
*/
public Instant plus(ReadableDuration duration) {
return withDurationAdded(duration, 1);
}
//-----------------------------------------------------------------------
/**
* Gets a copy of this instant with the specified duration taken away.
* <p>
* If the amount is zero or null, then <code>this</code> is returned.
*
* @param duration the duration to reduce this instant by
* @return a copy of this instant with the duration taken away
* @throws ArithmeticException if the new instant exceeds the capacity of a long
*/
public Instant minus(long duration) {
return withDurationAdded(duration, -1);
}
/**
* Gets a copy of this instant with the specified duration taken away.
* <p>
* If the amount is zero or null, then <code>this</code> is returned.
*
* @param duration the duration to reduce this instant by
* @return a copy of this instant with the duration taken away
* @throws ArithmeticException if the new instant exceeds the capacity of a long
*/
public Instant minus(ReadableDuration duration) {
return withDurationAdded(duration, -1);
}
//-----------------------------------------------------------------------
/**
* Gets the milliseconds of the instant.
*
* @return the number of milliseconds since 1970-01-01T00:00:00Z
*/
public long getMillis() {
return iMillis;
}
/**
* Gets the chronology of the instant, which is ISO in the UTC zone.
* <p>
* This method returns {@link ISOChronology#getInstanceUTC()} which
* corresponds to the definition of the Java epoch 1970-01-01T00:00:00Z.
*
* @return ISO in the UTC zone
*/
public Chronology getChronology() {
return ISOChronology.getInstanceUTC();
}
//-----------------------------------------------------------------------
/**
* Get this object as a DateTime using ISOChronology in the default zone.
* <p>
* This method returns a DateTime object in the default zone.
* This differs from the similarly named method on DateTime, DateMidnight
* or MutableDateTime which retains the time zone. The difference is
* because Instant really represents a time <i>without</i> a zone,
* thus calling this method we really have no zone to 'retain' and
* hence expect to switch to the default zone.
* <p>
* This method definition preserves compatibility with earlier versions
* of Joda-Time.
*
* @return a DateTime using the same millis
*/
public DateTime toDateTime() {
return new DateTime(getMillis(), ISOChronology.getInstance());
}
/**
* Get this object as a DateTime using ISOChronology in the default zone.
* This method is identical to <code>toDateTime()</code>.
* <p>
* This method returns a DateTime object in the default zone.
* This differs from the similarly named method on DateTime, DateMidnight
* or MutableDateTime which retains the time zone. The difference is
* because Instant really represents a time <i>without</i> a zone,
* thus calling this method we really have no zone to 'retain' and
* hence expect to switch to the default zone.
* <p>
* This method is deprecated because it is a duplicate of {@link #toDateTime()}.
* However, removing it would cause the superclass implementation to be used,
* which would create silent bugs in any caller depending on this implementation.
* As such, the method itself is not currently planned to be removed.
* <p>
* This method definition preserves compatibility with earlier versions
* of Joda-Time.
*
* @return a DateTime using the same millis with ISOChronology
* @deprecated Use toDateTime() as it is identical
*/
@Deprecated
public DateTime toDateTimeISO() {
return toDateTime();
}
/**
* Get this object as a MutableDateTime using ISOChronology in the default zone.
* <p>
* This method returns a MutableDateTime object in the default zone.
* This differs from the similarly named method on DateTime, DateMidnight
* or MutableDateTime which retains the time zone. The difference is
* because Instant really represents a time <i>without</i> a zone,
* thus calling this method we really have no zone to 'retain' and
* hence expect to switch to the default zone.
* <p>
* This method definition preserves compatibility with earlier versions
* of Joda-Time.
*
* @return a MutableDateTime using the same millis
*/
public MutableDateTime toMutableDateTime() {
return new MutableDateTime(getMillis(), ISOChronology.getInstance());
}
/**
* Get this object as a MutableDateTime using ISOChronology in the default zone.
* This method is identical to <code>toMutableDateTime()</code>.
* <p>
* This method returns a MutableDateTime object in the default zone.
* This differs from the similarly named method on DateTime, DateMidnight
* or MutableDateTime which retains the time zone. The difference is
* because Instant really represents a time <i>without</i> a zone,
* thus calling this method we really have no zone to 'retain' and
* hence expect to switch to the default zone.
* <p>
* This method is deprecated because it is a duplicate of {@link #toMutableDateTime()}.
* However, removing it would cause the superclass implementation to be used,
* which would create silent bugs in any caller depending on this implementation.
* As such, the method itself is not currently planned to be removed.
* <p>
* This method definition preserves compatibility with earlier versions
* of Joda-Time.
*
* @return a MutableDateTime using the same millis with ISOChronology
* @deprecated Use toMutableDateTime() as it is identical
*/
@Deprecated
public MutableDateTime toMutableDateTimeISO() {
return toMutableDateTime();
}
}