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/*
 *      Copyright (C) 2012-2015 DataStax Inc.
 *
 *   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 com.datastax.driver.core;

import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.TimeZone;
import java.util.concurrent.TimeUnit;

import static com.google.common.base.Preconditions.checkArgument;

/**
 * A date with no time components, no time zone, in the ISO 8601 calendar.
 * 

* Note that ISO 8601 has a number of differences with the default gregorian calendar used in Java: *

    *
  • it uses a proleptic gregorian calendar, meaning that it's gregorian indefinitely back in the past (there is no gregorian change);
  • *
  • there is a year 0.
  • *
*

* This class implements these differences, so that year/month/day fields match exactly the ones in * CQL string literals. * * @since 2.2 */ public final class LocalDate { private static final TimeZone UTC = TimeZone.getTimeZone("UTC"); private final long millisSinceEpoch; private final int daysSinceEpoch; // This gets initialized lazily if we ever need it. Once set, it is effectively immutable. private volatile GregorianCalendar calendar; private LocalDate(int daysSinceEpoch) { this.daysSinceEpoch = daysSinceEpoch; this.millisSinceEpoch = TimeUnit.DAYS.toMillis(daysSinceEpoch); } /** * Builds a new instance from a number of days since January 1st, 1970 GMT. * * @param daysSinceEpoch the number of days. * @return the new instance. */ public static LocalDate fromDaysSinceEpoch(int daysSinceEpoch) { return new LocalDate(daysSinceEpoch); } /** * Builds a new instance from a number of milliseconds since January 1st, 1970 GMT. * Note that if the given number does not correspond to a whole number of days, * it will be rounded towards 0. * * @param millisSinceEpoch the number of milliseconds since January 1st, 1970 GMT. * @return the new instance. * @throws IllegalArgumentException if the date is not in the range [-5877641-06-23; 5881580-07-11]. */ public static LocalDate fromMillisSinceEpoch(long millisSinceEpoch) throws IllegalArgumentException { long daysSinceEpoch = TimeUnit.MILLISECONDS.toDays(millisSinceEpoch); checkArgument(daysSinceEpoch >= Integer.MIN_VALUE && daysSinceEpoch <= Integer.MAX_VALUE, "Date should be in the range [-5877641-06-23; 5881580-07-11]"); return new LocalDate((int) daysSinceEpoch); } /** * Builds a new instance from a year/month/day specification. *

* This method is not lenient, i.e. '2014-12-32' will not be treated as '2015-01-01', but * instead throw an {@code IllegalArgumentException}. * * @param year the year in ISO format (see {@link LocalDate this class's Javadoc}). * @param month the month. It is 1-based (e.g. 1 for January). * @param dayOfMonth the day of the month. * @return the new instance. * @throws IllegalArgumentException if the corresponding date does not exist in the ISO8601 * calendar. */ public static LocalDate fromYearMonthDay(int year, int month, int dayOfMonth) { int calendarYear = (year <= 0) ? -year + 1 : year; int calendarEra = (year <= 0) ? GregorianCalendar.BC : GregorianCalendar.AD; GregorianCalendar calendar = isoCalendar(); // We can't allow leniency because that could mess with our year shift above (for example if the arguments were 0, 12, 32) calendar.setLenient(false); calendar.clear(); calendar.set(calendarYear, month - 1, dayOfMonth, 0, 0, 0); calendar.set(Calendar.ERA, calendarEra); LocalDate date = fromMillisSinceEpoch(calendar.getTimeInMillis()); date.calendar = calendar; return date; } /** * Returns the number of days since January 1st, 1970 GMT. * * @return the number of days. */ public int getDaysSinceEpoch() { return daysSinceEpoch; } /** * Returns the number of milliseconds since January 1st, 1970 GMT. * * @return the number of milliseconds. */ public long getMillisSinceEpoch() { return millisSinceEpoch; } /** * Returns the year. * * @return the year. */ public int getYear() { GregorianCalendar c = getCalendar(); int year = c.get(Calendar.YEAR); if (c.get(Calendar.ERA) == GregorianCalendar.BC) year = -year + 1; return year; } /** * Returns the month. * * @return the month. It is 1-based, e.g. 1 for January. */ public int getMonth() { return getCalendar().get(Calendar.MONTH) + 1; } /** * Returns the day in the month. * * @return the day in the month. */ public int getDay() { return getCalendar().get(Calendar.DAY_OF_MONTH); } /** * Return a new {@link LocalDate} with the specified (signed) amount * of time added to (or subtracted from) the given {@link Calendar} field, * based on the calendar's rules. *

* Note that adding any amount to a field smaller than * {@link Calendar#DAY_OF_MONTH} will remain without effect, * as this class does not keep time components. *

* See {@link Calendar} javadocs for more information. * * @param field a {@link Calendar} field to modify. * @param amount the amount of date or time to be added to the field. * @return a new {@link LocalDate} with the specified (signed) amount * of time added to (or subtracted from) the given {@link Calendar} field. * @throws IllegalArgumentException if the new date is not in the range [-5877641-06-23; 5881580-07-11]. */ public LocalDate add(int field, int amount) { GregorianCalendar newCalendar = isoCalendar(); newCalendar.setTimeInMillis(millisSinceEpoch); newCalendar.add(field, amount); LocalDate newDate = fromMillisSinceEpoch(newCalendar.getTimeInMillis()); newDate.calendar = newCalendar; return newDate; } @Override public boolean equals(Object o) { if (this == o) return true; if (o instanceof LocalDate) { LocalDate that = (LocalDate) o; return this.daysSinceEpoch == that.daysSinceEpoch; } return false; } @Override public int hashCode() { return daysSinceEpoch; } @Override public String toString() { return String.format("%d-%s-%s", getYear(), pad2(getMonth()), pad2(getDay())); } private static String pad2(int i) { String s = Integer.toString(i); return s.length() == 2 ? s : "0" + s; } private GregorianCalendar getCalendar() { // Two threads can race and both create a calendar. This is not a problem. if (calendar == null) { // Use a local variable to only expose after we're done mutating it. GregorianCalendar tmp = isoCalendar(); tmp.setTimeInMillis(millisSinceEpoch); calendar = tmp; } return calendar; } // This matches what Cassandra uses server side (from Joda Time's LocalDate) private static GregorianCalendar isoCalendar() { GregorianCalendar calendar = new GregorianCalendar(UTC); calendar.setGregorianChange(new Date(Long.MIN_VALUE)); return calendar; } }





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