http://www.joda.org/joda-time/: Date and time library to replace JDK date handling (Joda.org) 
/*
 *  Copyright 2001-2013 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.lang.reflect.Method;
import java.text.DateFormatSymbols;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Locale;
import java.util.Map;
import java.util.concurrent.atomic.AtomicReference;

import org.joda.time.chrono.ISOChronology;


DateTimeUtils provide public utility methods for the date-time library.


DateTimeUtils uses shared static variables which are declared as volatile
for thread-safety. These can be changed during the lifetime of the application
however doing so is generally a bad idea.

Author:Stephen Colebourne
Since:1.0
/**
 * DateTimeUtils provide public utility methods for the date-time library.
 * <p>
 * DateTimeUtils uses shared static variables which are declared as volatile
 * for thread-safety. These can be changed during the lifetime of the application
 * however doing so is generally a bad idea.
 *
 * @author Stephen Colebourne
 * @since 1.0
 */
public class DateTimeUtils {

    
The singleton instance of the system millisecond provider.

/**
     * The singleton instance of the system millisecond provider.
     */
    public static final MillisProvider SYSTEM_MILLIS_PROVIDER = new SystemMillisProvider();

    
The millisecond provider currently in use. 
/** The millisecond provider currently in use. */
    private static volatile MillisProvider cMillisProvider = SYSTEM_MILLIS_PROVIDER;
    
The default names.
This is lazily initialized to reduce risks of race conditions at startup.

/**
     * The default names.
     * This is lazily initialized to reduce risks of race conditions at startup.
     */
    private static final AtomicReference<Map<String, DateTimeZone>> cZoneNames =
                    new AtomicReference<Map<String,DateTimeZone>>();

    
Restrictive constructor

/**
     * Restrictive constructor
     */
    protected DateTimeUtils() {
        super();
    }

    //-----------------------------------------------------------------------
    
Gets the current time in milliseconds.


By default this returns System.currentTimeMillis().
This may be changed using other methods in this class.

Returns:the current time in milliseconds from 1970-01-01T00:00:00Z
/**
     * Gets the current time in milliseconds.
     * <p>
     * By default this returns <code>System.currentTimeMillis()</code>.
     * This may be changed using other methods in this class.
     * 
     * @return the current time in milliseconds from 1970-01-01T00:00:00Z
     */
    public static final long currentTimeMillis() {
        return cMillisProvider.getMillis();
    }

    
Resets the current time to return the system time.

 This method changes the behaviour of currentTimeMillis(). Whenever the current time is queried, System.currentTimeMillis() is used. 
Throws:
/**
     * Resets the current time to return the system time.
     * <p>
     * This method changes the behaviour of {@link #currentTimeMillis()}.
     * Whenever the current time is queried, {@link System#currentTimeMillis()} is used.
     * 
     * @throws SecurityException if the application does not have sufficient security rights
     */
    public static final void setCurrentMillisSystem() throws SecurityException {
        checkPermission();
        cMillisProvider = SYSTEM_MILLIS_PROVIDER;
    }

    
Sets the current time to return a fixed millisecond time.

 This method changes the behaviour of currentTimeMillis(). Whenever the current time is queried, the same millisecond time will be returned. 
Params:
  • fixedMillis –  the fixed millisecond time to use
Throws:
/**
     * Sets the current time to return a fixed millisecond time.
     * <p>
     * This method changes the behaviour of {@link #currentTimeMillis()}.
     * Whenever the current time is queried, the same millisecond time will be returned.
     * 
     * @param fixedMillis  the fixed millisecond time to use
     * @throws SecurityException if the application does not have sufficient security rights
     */
    public static final void setCurrentMillisFixed(long fixedMillis) throws SecurityException {
        checkPermission();
        cMillisProvider = new FixedMillisProvider(fixedMillis);
    }

    
Sets the current time to return the system time plus an offset.

 This method changes the behaviour of currentTimeMillis(). Whenever the current time is queried, System.currentTimeMillis() is used and then offset by adding the millisecond value specified here. 
Params:
  • offsetMillis –  the fixed millisecond time to use
Throws:
/**
     * Sets the current time to return the system time plus an offset.
     * <p>
     * This method changes the behaviour of {@link #currentTimeMillis()}.
     * Whenever the current time is queried, {@link System#currentTimeMillis()} is used
     * and then offset by adding the millisecond value specified here.
     * 
     * @param offsetMillis  the fixed millisecond time to use
     * @throws SecurityException if the application does not have sufficient security rights
     */
    public static final void setCurrentMillisOffset(long offsetMillis) throws SecurityException {
        checkPermission();
        if (offsetMillis == 0) {
            cMillisProvider = SYSTEM_MILLIS_PROVIDER;
        } else {
            cMillisProvider = new OffsetMillisProvider(offsetMillis);
        }
    }

    
Sets the provider of the current time to class specified.

 This method changes the behaviour of currentTimeMillis(). Whenever the current time is queried, the specified class will be called. 
Params:
  • millisProvider –  the provider of the current time to use, not null
Throws:
Since:2.0
/**
     * Sets the provider of the current time to class specified.
     * <p>
     * This method changes the behaviour of {@link #currentTimeMillis()}.
     * Whenever the current time is queried, the specified class will be called.
     * 
     * @param millisProvider  the provider of the current time to use, not null
     * @throws SecurityException if the application does not have sufficient security rights
     * @since 2.0
     */
    public static final void setCurrentMillisProvider(MillisProvider millisProvider) throws SecurityException {
        if (millisProvider == null) {
            throw new IllegalArgumentException("The MillisProvider must not be null");
        }
        checkPermission();
        cMillisProvider = millisProvider;
    }

    
Checks whether the provider may be changed using permission 'CurrentTime.setProvider'.

Throws:
  • SecurityException – if the provider may not be changed
/**
     * Checks whether the provider may be changed using permission 'CurrentTime.setProvider'.
     * 
     * @throws SecurityException if the provider may not be changed
     */
    private static void checkPermission() throws SecurityException {
        SecurityManager sm = System.getSecurityManager();
        if (sm != null) {
            sm.checkPermission(new JodaTimePermission("CurrentTime.setProvider"));
        }
    }

    //-----------------------------------------------------------------------
    
Gets the millisecond instant from the specified instant object handling null.


If the instant object is null, the currentTimeMillis() will be returned. Otherwise, the millis from the object are returned. 
Params:
  • instant –  the instant to examine, null means now
Returns:the time in milliseconds from 1970-01-01T00:00:00Z
/**
     * Gets the millisecond instant from the specified instant object handling null.
     * <p>
     * If the instant object is <code>null</code>, the {@link #currentTimeMillis()}
     * will be returned. Otherwise, the millis from the object are returned.
     * 
     * @param instant  the instant to examine, null means now
     * @return the time in milliseconds from 1970-01-01T00:00:00Z
     */
    public static final long getInstantMillis(ReadableInstant instant) {
        if (instant == null) {
            return DateTimeUtils.currentTimeMillis();
        }
        return instant.getMillis();
    }

    //-----------------------------------------------------------------------
    
Gets the chronology from the specified instant object handling null.


If the instant object is null, or the instant's chronology is
null, ISOChronology.getInstance() will be returned. Otherwise, the chronology from the object is returned. 
Params:
  • instant –  the instant to examine, null means ISO in the default zone
Returns:the chronology, never null
/**
     * Gets the chronology from the specified instant object handling null.
     * <p>
     * If the instant object is <code>null</code>, or the instant's chronology is
     * <code>null</code>, {@link ISOChronology#getInstance()} will be returned.
     * Otherwise, the chronology from the object is returned.
     * 
     * @param instant  the instant to examine, null means ISO in the default zone
     * @return the chronology, never null
     */
    public static final Chronology getInstantChronology(ReadableInstant instant) {
        if (instant == null) {
            return ISOChronology.getInstance();
        }
        Chronology chrono = instant.getChronology();
        if (chrono == null) {
            return ISOChronology.getInstance();
        }
        return chrono;
    }

    //-----------------------------------------------------------------------
    
Gets the chronology from the specified instant based interval handling null.

 The chronology is obtained from the start if that is not null, or from the end if the start is null. The result is additionally checked, and if still null then ISOChronology.getInstance() will be returned. 
Params:
  • start –  the instant to examine and use as the primary source of the chronology
  • end –  the instant to examine and use as the secondary source of the chronology
Returns:the chronology, never null
/**
     * Gets the chronology from the specified instant based interval handling null.
     * <p>
     * The chronology is obtained from the start if that is not null, or from the
     * end if the start is null. The result is additionally checked, and if still
     * null then {@link ISOChronology#getInstance()} will be returned.
     * 
     * @param start  the instant to examine and use as the primary source of the chronology
     * @param end  the instant to examine and use as the secondary source of the chronology
     * @return the chronology, never null
     */
    public static final Chronology getIntervalChronology(ReadableInstant start, ReadableInstant end) {
        Chronology chrono = null;
        if (start != null) {
            chrono = start.getChronology();
        } else if (end != null) {
            chrono = end.getChronology();
        }
        if (chrono == null) {
            chrono = ISOChronology.getInstance();
        }
        return chrono;
    }

    //-----------------------------------------------------------------------
    
Gets the chronology from the specified interval object handling null.


If the interval object is null, or the interval's chronology is
null, ISOChronology.getInstance() will be returned. Otherwise, the chronology from the object is returned. 
Params:
  • interval –  the interval to examine, null means ISO in the default zone
Returns:the chronology, never null
/**
     * Gets the chronology from the specified interval object handling null.
     * <p>
     * If the interval object is <code>null</code>, or the interval's chronology is
     * <code>null</code>, {@link ISOChronology#getInstance()} will be returned.
     * Otherwise, the chronology from the object is returned.
     * 
     * @param interval  the interval to examine, null means ISO in the default zone
     * @return the chronology, never null
     */
    public static final Chronology getIntervalChronology(ReadableInterval interval) {
        if (interval == null) {
            return ISOChronology.getInstance();
        }
        Chronology chrono = interval.getChronology();
        if (chrono == null) {
            return ISOChronology.getInstance();
        }
        return chrono;
    }

    //-----------------------------------------------------------------------
    
Gets the interval handling null.


If the interval is null, an interval representing now to now in the ISOChronology will be returned. Otherwise, the interval specified is returned. 
Params:
  • interval –  the interval to use, null means now to now
Returns:the interval, never null
Since:1.1
/**
     * Gets the interval handling null.
     * <p>
     * If the interval is <code>null</code>, an interval representing now
     * to now in the {@link ISOChronology#getInstance() ISOChronology}
     * will be returned. Otherwise, the interval specified is returned.
     * 
     * @param interval  the interval to use, null means now to now
     * @return the interval, never null
     * @since 1.1
     */
    public static final ReadableInterval getReadableInterval(ReadableInterval interval) {
        if (interval == null) {
            long now = DateTimeUtils.currentTimeMillis();
            interval = new Interval(now, now);
        }
        return interval;
    }

    //-----------------------------------------------------------------------
    
Gets the chronology handling null.


If the chronology is null, ISOChronology.getInstance() will be returned. Otherwise, the chronology is returned. 
Params:
  • chrono –  the chronology to use, null means ISO in the default zone
Returns:the chronology, never null
/**
     * Gets the chronology handling null.
     * <p>
     * If the chronology is <code>null</code>, {@link ISOChronology#getInstance()}
     * will be returned. Otherwise, the chronology is returned.
     * 
     * @param chrono  the chronology to use, null means ISO in the default zone
     * @return the chronology, never null
     */
    public static final Chronology getChronology(Chronology chrono) {
        if (chrono == null) {
            return ISOChronology.getInstance();
        }
        return chrono;
    }

    //-----------------------------------------------------------------------
    
Gets the zone handling null.


If the zone is null, DateTimeZone.getDefault() will be returned. Otherwise, the zone specified is returned. 
Params:
  • zone –  the time zone to use, null means the default zone
Returns:the time zone, never null
/**
     * Gets the zone handling null.
     * <p>
     * If the zone is <code>null</code>, {@link DateTimeZone#getDefault()}
     * will be returned. Otherwise, the zone specified is returned.
     * 
     * @param zone  the time zone to use, null means the default zone
     * @return the time zone, never null
     */
    public static final DateTimeZone getZone(DateTimeZone zone) {
        if (zone == null) {
            return DateTimeZone.getDefault();
        }
        return zone;
    }

    //-----------------------------------------------------------------------
    
Gets the period type handling null.


If the zone is null, PeriodType.standard() will be returned. Otherwise, the type specified is returned. 
Params:
  • type –  the time zone to use, null means the standard type
Returns:the type to use, never null
/**
     * Gets the period type handling null.
     * <p>
     * If the zone is <code>null</code>, {@link PeriodType#standard()}
     * will be returned. Otherwise, the type specified is returned.
     * 
     * @param type  the time zone to use, null means the standard type
     * @return the type to use, never null
     */
    public static final PeriodType getPeriodType(PeriodType type) {
        if (type == null) {
            return PeriodType.standard();
        }
        return type;
    }

    //-----------------------------------------------------------------------
    
Gets the millisecond duration from the specified duration object handling null.


If the duration object is null, zero will be returned.
Otherwise, the millis from the object are returned.

Params:
  • duration –  the duration to examine, null means zero
Returns:the duration in milliseconds
/**
     * Gets the millisecond duration from the specified duration object handling null.
     * <p>
     * If the duration object is <code>null</code>, zero will be returned.
     * Otherwise, the millis from the object are returned.
     * 
     * @param duration  the duration to examine, null means zero
     * @return the duration in milliseconds
     */
    public static final long getDurationMillis(ReadableDuration duration) {
        if (duration == null) {
            return 0L;
        }
        return duration.getMillis();
    }

    //-----------------------------------------------------------------------
    
Checks whether the partial is contiguous.


A partial is contiguous if one field starts where another ends.


For example LocalDate is contiguous because DayOfMonth has
the same range (Month) as the unit of the next field (MonthOfYear), and
MonthOfYear has the same range (Year) as the unit of the next field (Year).


Similarly, LocalTime is contiguous, as it consists of
MillisOfSecond, SecondOfMinute, MinuteOfHour and HourOfDay (note how
the names of each field 'join up').


However, a Year/HourOfDay partial is not contiguous because the range
field Day is not equal to the next field Year.
Similarly, a DayOfWeek/DayOfMonth partial is not contiguous because
the range Month is not equal to the next field Day.

Params:
  • partial –  the partial to check
Throws:
Returns:true if the partial is contiguous
Since:1.1
/**
     * Checks whether the partial is contiguous.
     * <p>
     * A partial is contiguous if one field starts where another ends.
     * <p>
     * For example <code>LocalDate</code> is contiguous because DayOfMonth has
     * the same range (Month) as the unit of the next field (MonthOfYear), and
     * MonthOfYear has the same range (Year) as the unit of the next field (Year).
     * <p>
     * Similarly, <code>LocalTime</code> is contiguous, as it consists of
     * MillisOfSecond, SecondOfMinute, MinuteOfHour and HourOfDay (note how
     * the names of each field 'join up').
     * <p>
     * However, a Year/HourOfDay partial is not contiguous because the range
     * field Day is not equal to the next field Year.
     * Similarly, a DayOfWeek/DayOfMonth partial is not contiguous because
     * the range Month is not equal to the next field Day.
     * 
     * @param partial  the partial to check
     * @return true if the partial is contiguous
     * @throws IllegalArgumentException if the partial is null
     * @since 1.1
     */
    public static final boolean isContiguous(ReadablePartial partial) {
        if (partial == null) {
            throw new IllegalArgumentException("Partial must not be null");
        }
        DurationFieldType lastType = null;
        for (int i = 0; i < partial.size(); i++) {
            DateTimeField loopField = partial.getField(i);
            if (i > 0) {
                if (loopField.getRangeDurationField() == null || loopField.getRangeDurationField().getType() != lastType) {
                    return false;
                }
            }
            lastType = loopField.getDurationField().getType();
        }
        return true;
    }

    //-----------------------------------------------------------------------
    
Gets the DateFormatSymbols based on the given locale. 
 If JDK 6 or newer is being used, DateFormatSymbols.getInstance(locale) will be used in order to allow the use of locales defined as extensions. Otherwise, new DateFormatSymbols(locale) will be used. See JDK 6 DateFormatSymbols for further information. 
Params:
Returns:the symbols
Since:2.0
/**
     * Gets the {@link DateFormatSymbols} based on the given locale.
     * <p>
     * If JDK 6 or newer is being used, DateFormatSymbols.getInstance(locale) will
     * be used in order to allow the use of locales defined as extensions.
     * Otherwise, new DateFormatSymbols(locale) will be used.
     * See JDK 6 {@link DateFormatSymbols} for further information.
     * 
     * @param locale  the {@link Locale} used to get the correct {@link DateFormatSymbols}
     * @return the symbols
     * @since 2.0
     */
    public static final DateFormatSymbols getDateFormatSymbols(Locale locale) {
        try {
            Method method = DateFormatSymbols.class.getMethod("getInstance", new Class[] {Locale.class});
            return (DateFormatSymbols) method.invoke(null, new Object[] {locale});
        } catch (Exception ex) {
            return new DateFormatSymbols(locale);
        }
    }

    //-----------------------------------------------------------------------
    
Gets the default map of time zone names.

 This can be changed by setDefaultTimeZoneNames. 

The default set of short time zone names is as follows:

    

  • UT - UTC

  • UTC - UTC

  • GMT - UTC

  • EST - America/New_York

  • EDT - America/New_York

  • CST - America/Chicago

  • CDT - America/Chicago

  • MST - America/Denver

  • MDT - America/Denver

  • PST - America/Los_Angeles

  • PDT - America/Los_Angeles



Returns:the unmodifiable map of abbreviations to zones, not null
Since:2.2
/**
     * Gets the default map of time zone names.
     * <p>
     * This can be changed by {@link #setDefaultTimeZoneNames}.
     * <p>
     * The default set of short time zone names is as follows:
     * <ul>
     * <li>UT - UTC
     * <li>UTC - UTC
     * <li>GMT - UTC
     * <li>EST - America/New_York
     * <li>EDT - America/New_York
     * <li>CST - America/Chicago
     * <li>CDT - America/Chicago
     * <li>MST - America/Denver
     * <li>MDT - America/Denver
     * <li>PST - America/Los_Angeles
     * <li>PDT - America/Los_Angeles
     * </ul>
     * 
     * @return the unmodifiable map of abbreviations to zones, not null
     * @since 2.2
     */
    public static final Map<String, DateTimeZone> getDefaultTimeZoneNames() {
        Map<String, DateTimeZone> names = cZoneNames.get();
        if (names == null) {
            names = buildDefaultTimeZoneNames();
            if (!cZoneNames.compareAndSet(null, names)) {
                names = cZoneNames.get();
            }
        }
        return names;
    }

    
Sets the default map of time zone names.


The map is copied before storage.

Params:
  • names –  the map of abbreviations to zones, not null
Since:2.2
/**
     * Sets the default map of time zone names.
     * <p>
     * The map is copied before storage.
     * 
     * @param names  the map of abbreviations to zones, not null
     * @since 2.2
     */
    public static final void setDefaultTimeZoneNames(Map<String, DateTimeZone> names) {
        cZoneNames.set(Collections.unmodifiableMap(new HashMap<String, DateTimeZone>(names)));
    }

    private static Map<String, DateTimeZone> buildDefaultTimeZoneNames() {
        // names from RFC-822 / JDK
        // this is all very US-centric and dubious, but perhaps it will help some
        Map<String, DateTimeZone> map = new LinkedHashMap<String, DateTimeZone>();
        map.put("UT", DateTimeZone.UTC);
        map.put("UTC", DateTimeZone.UTC);
        map.put("GMT", DateTimeZone.UTC);
        put(map, "EST", "America/New_York");
        put(map, "EDT", "America/New_York");
        put(map, "CST", "America/Chicago");
        put(map, "CDT", "America/Chicago");
        put(map, "MST", "America/Denver");
        put(map, "MDT", "America/Denver");
        put(map, "PST", "America/Los_Angeles");
        put(map, "PDT", "America/Los_Angeles");
        return Collections.unmodifiableMap(map);
    }
    private static void put(Map<String, DateTimeZone> map, String name, String id) {
        try {
            map.put(name, DateTimeZone.forID(id));
        } catch (RuntimeException ex) {
            // ignore
        }
    }
    //-------------------------------------------------------------------------
    
Calculates the astronomical Julian Day for an instant.


The Julian day is a well-known
system of time measurement for scientific use by the astronomy community.
It expresses the interval of time in days and fractions of a day since
January 1, 4713 BC (Julian) Greenwich noon.


Each day starts at midday (not midnight) and time is expressed as a fraction.
Thus the fraction 0.25 is 18:00. equal to one quarter of the day from midday to midday.


Note that this method has nothing to do with the day-of-year.

Params:
  • epochMillis –  the epoch millis from 1970-01-01Z
Returns:the astronomical Julian Day represented by the specified instant
Since:2.2
/**
     * Calculates the astronomical Julian Day for an instant.
     * <p>
     * The <a href="http://en.wikipedia.org/wiki/Julian_day">Julian day</a> is a well-known
     * system of time measurement for scientific use by the astronomy community.
     * It expresses the interval of time in days and fractions of a day since
     * January 1, 4713 BC (Julian) Greenwich noon.
     * <p>
     * Each day starts at midday (not midnight) and time is expressed as a fraction.
     * Thus the fraction 0.25 is 18:00. equal to one quarter of the day from midday to midday.
     * <p>
     * Note that this method has nothing to do with the day-of-year.
     * 
     * @param epochMillis  the epoch millis from 1970-01-01Z
     * @return the astronomical Julian Day represented by the specified instant
     * @since 2.2
     */
    public static final double toJulianDay(long epochMillis) {
        // useful links
        // http://en.wikipedia.org/wiki/Julian_day#cite_note-13 - Wikipedia
        // http://aa.usno.navy.mil/data/docs/JulianDate.php" - USNO
        // http://users.zoominternet.net/~matto/Java/Julian%20Date%20Converter.htm - Julian Date Converter by Matt Oltersdorf
        // http://ssd.jpl.nasa.gov/tc.cgi#top - CalTech
        double epochDay = epochMillis / 86400000d;
        return epochDay + 2440587.5d;
    }

    
Calculates the astronomical Julian Day Number for an instant.

 The toJulianDay(long) method calculates the astronomical Julian Day with a fraction based on days starting at midday. This method calculates the variant where days start at midnight. JDN 0 is used for the date equivalent to Monday January 1, 4713 BC (Julian). Thus these days start 12 hours before those of the fractional Julian Day. 

Note that this method has nothing to do with the day-of-year.

Params:
  • epochMillis –  the epoch millis from 1970-01-01Z
Returns:the astronomical Julian Day represented by the specified instant
Since:2.2
/**
     * Calculates the astronomical Julian Day Number for an instant.
     * <p>
     * The {@link #toJulianDay(long)} method calculates the astronomical Julian Day
     * with a fraction based on days starting at midday.
     * This method calculates the variant where days start at midnight.
     * JDN 0 is used for the date equivalent to Monday January 1, 4713 BC (Julian).
     * Thus these days start 12 hours before those of the fractional Julian Day.
     * <p>
     * Note that this method has nothing to do with the day-of-year.
     * 
     * @param epochMillis  the epoch millis from 1970-01-01Z
     * @return the astronomical Julian Day represented by the specified instant
     * @since 2.2
     */
    public static final long toJulianDayNumber(long epochMillis) {
        return (long) Math.floor(toJulianDay(epochMillis) + 0.5d);
    }

    
Creates a date-time from a Julian Day.

 Returns the DateTime object equal to the specified Julian Day. 
Params:
  • julianDay –  the Julian Day
Returns:the epoch millis from 1970-01-01Z
Since:2.2
/**
     * Creates a date-time from a Julian Day.
     * <p>
     * Returns the {@code DateTime} object equal to the specified Julian Day.
     * 
     * @param julianDay  the Julian Day
     * @return the epoch millis from 1970-01-01Z
     * @since 2.2
     */
    public static final long fromJulianDay(double julianDay) {
        double epochDay = julianDay - 2440587.5d;
        return (long) (epochDay * 86400000d);
    }

    //-----------------------------------------------------------------------
    
A millisecond provider, allowing control of the system clock.

Author:Stephen Colebourne
Since:2.0 (previously private)
/**
     * A millisecond provider, allowing control of the system clock.
     * 
     * @author Stephen Colebourne
     * @since 2.0 (previously private)
     */
    public static interface MillisProvider {
        
Gets the current time.


Implementations of this method must be thread-safe.

Returns:the current time in milliseconds
/**
         * Gets the current time.
         * <p>
         * Implementations of this method must be thread-safe.
         * 
         * @return the current time in milliseconds
         */
        long getMillis();
    }

    
System millis provider.

/**
     * System millis provider.
     */
    static class SystemMillisProvider implements MillisProvider {
        
Gets the current time.

Returns:the current time in millis
/**
         * Gets the current time.
         * @return the current time in millis
         */
        public long getMillis() {
            return System.currentTimeMillis();
        }
    }

    
Fixed millisecond provider.

/**
     * Fixed millisecond provider.
     */
    static class FixedMillisProvider implements MillisProvider {
        
The fixed millis value. 
/** The fixed millis value. */
        private final long iMillis;
        
        
Constructor.

Params:
  • fixedMillis –  the millis value
/**
         * Constructor.
         * @param fixedMillis  the millis value
         */
        FixedMillisProvider(long fixedMillis) {
            iMillis = fixedMillis;
        }
        
        
Gets the current time.

Returns:the current time in millis
/**
         * Gets the current time.
         * @return the current time in millis
         */
        public long getMillis() {
            return iMillis;
        }
    }

    
Offset from system millis provider.

/**
     * Offset from system millis provider.
     */
    static class OffsetMillisProvider implements MillisProvider {
        
The millis offset. 
/** The millis offset. */
        private final long iMillis;
        
        
Constructor.

Params:
  • offsetMillis –  the millis offset
/**
         * Constructor.
         * @param offsetMillis  the millis offset
         */
        OffsetMillisProvider(long offsetMillis) {
            iMillis = offsetMillis;
        }
        
        
Gets the current time.

Returns:the current time in millis
/**
         * Gets the current time.
         * @return the current time in millis
         */
        public long getMillis() {
            return System.currentTimeMillis() + iMillis;
        }
    }

}