org.ojai.types.ODate.java Source code

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Here is the source code for org.ojai.types.ODate.java

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/**
 * Copyright (c) 2015 MapR, 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 org.ojai.types;

import java.io.Serializable;
import java.util.Date;

import org.joda.time.Days;
import org.joda.time.LocalDate;
import org.joda.time.LocalTime;
import org.ojai.Value.Type;
import org.ojai.annotation.API;
import org.ojai.exceptions.ParseException;

/**
 * An immutable class which encapsulates an OJAI {@link Type#DATE DATE} type.
 */
@API.Public
public final class ODate implements Comparable<ODate>, Serializable {

    private static final long serialVersionUID = 0xaffa9a5dfe3ff863L;

    private static final LocalDate EPOCH_DATE = new LocalDate(1970, 1, 1);
    private static final LocalTime START_OF_DAY = new LocalTime(0, 0, 0);

    private transient volatile LocalDate date; // for lazy initialization

    /** number of days since Unix epoch */
    private final int daysSinceEpoch;

    /**
     * Parses and return an instance of {@code ODate} from the specified string.
     * @param dateStr  the string to parse
     * @exception ParseException if the beginning of the specified string
     *            cannot be parsed.
     */
    public static ODate parse(String dateStr) {
        try {
            return new ODate(LocalDate.parse(dateStr));
        } catch (IllegalArgumentException e) {
            throw new ParseException(e);
        }
    }

    /**
     * Return an {@code ODate} instance from the specified number of days since epoch.
     *
     * @param daysSinceEpoch the number of days since epoch
     */
    public static ODate fromDaysSinceEpoch(int daysSinceEpoch) {
        return new ODate(daysSinceEpoch);
    }

    /**
     * Constructs an {@code ODate} instance set to the specified year, month and
     * day of the month.
     *
     * @param year        the year
     * @param month       the month of the year, from 1 to 12
     * @param dayOfMonth  the day of the month, from 1 to 31
     */
    public ODate(int year, int month, int dayOfMonth) {
        this(new LocalDate(year, month, dayOfMonth));
    }

    /**
     * Constructs an {@code ODate} instance from the milliseconds value since the
     * Unix epoch. The DATE value is set to the calendar date in the default time
     * zone.
     *
     * @param epoh  the milliseconds from 1970-01-01T00:00:00.000 UTC
     */
    public ODate(long epoh) {
        this(new LocalDate(epoh));
    }

    /**
     * Constructs an {@code ODate} instance from a {@code java.util.Date} using
     * exactly the same field values. The DATE value is set to the calendar date
     * in the default time zone.
     *
     * @param date  the Date to extract fields from
     */
    public ODate(Date date) {
        this(LocalDate.fromDateFields(date));
    }

    /*
     * Private constructors.
     */
    private ODate(int daysSinceEpoch) {
        this.daysSinceEpoch = daysSinceEpoch;
    }

    private ODate(LocalDate localDate) {
        date = localDate;
        daysSinceEpoch = Days.daysBetween(EPOCH_DATE, date).getDays();
    }

    /**
     * @return The years value of this {@code Date} as an {@code int}.
     */
    public int getYear() {
        return getDate().getYear();
    }

    /**
     * @return The months value of this {@code Date} as an {@code int}.
     */
    public int getMonth() {
        return getDate().getMonthOfYear();
    }

    /**
     * @return The date of month value of this {@code Date} as an {@code int}.
     */
    public int getDayOfMonth() {
        return getDate().getDayOfMonth();
    }

    /**
     * @return The total number of days since the Unix epoch.
     */
    public int toDaysSinceEpoch() {
        return daysSinceEpoch;
    }

    /**
     * Get this DATE as a {@link java.util.Date} in the default timezone.
     * The time fields of the {@code Date} object is set to Unix 0.
     *
     * @return a Date initialized with this DATE
     */
    public Date toDate() {
        return getDate().toDateTime(START_OF_DAY).toDate();
    }

    /**
     * Returns a string representation of this date in ISO8601 format (yyyy-MM-dd).
     */
    public String toDateStr() {
        return toString("yyyy-MM-dd");
    }

    /**
     * Returns a string representation of this date using the specified format pattern.
     *
     * @param pattern  the pattern specification
     */
    public String toString(String pattern) {
        return getDate().toString(pattern);
    }

    @Override
    public String toString() {
        return toDateStr();
    }

    @Override
    public int hashCode() {
        return daysSinceEpoch;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        ODate other = (ODate) obj;
        if (daysSinceEpoch != other.daysSinceEpoch)
            return false;
        return true;
    }

    @Override
    public int compareTo(ODate o) {
        return daysSinceEpoch - o.daysSinceEpoch;
    }

    private LocalDate getDate() {
        if (date == null) {
            synchronized (this) {
                if (date == null) {
                    date = EPOCH_DATE.plusDays(daysSinceEpoch);
                }
            }
        }
        return date;
    }

}