001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      https://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.lang3.time;
019
020import java.time.ZoneId;
021import java.util.TimeZone;
022
023import org.apache.commons.lang3.JavaVersion;
024import org.apache.commons.lang3.ObjectUtils;
025import org.apache.commons.lang3.SystemProperties;
026import org.apache.commons.lang3.SystemUtils;
027
028/**
029 * Helps dealing with {@link java.util.TimeZone}s.
030 *
031 * @since 3.7
032 */
033public class TimeZones {
034
035    /**
036     * A public version of {@link java.util.TimeZone}'s package private {@code GMT_ID} field.
037     */
038    public static final String GMT_ID = "GMT";
039
040    /**
041     * The GMT time zone.
042     *
043     * @since 3.13.0
044     */
045    public static final TimeZone GMT = TimeZones.getTimeZone(GMT_ID);
046
047    private static final boolean JAVA_25 = SystemUtils.isJavaVersionAtLeast(JavaVersion.JAVA_25);
048
049    /**
050     * Delegates to {@link TimeZone#getTimeZone(String)}, on Java 25 and up, maps an ID if it's a key in {@link ZoneId#SHORT_IDS}.
051     * <p>
052     * On Java 25, calling {@link TimeZone#getTimeZone(String)} with an ID in {@link ZoneId#SHORT_IDS} writes a message to {@link System#err} in the form:
053     * </p>
054     *
055     * <pre>
056     * WARNING: Use of the three-letter time zone ID "the-short-id" is deprecated and it will be removed in a future release
057     * </pre>
058     * <p>
059     * You can disable mapping from {@link ZoneId#SHORT_IDS} by setting the system property {@code "TimeZones.mapShortIDs=false"}.
060     * </p>
061     *
062     * @param id Same as {@link TimeZone#getTimeZone(String)}.
063     * @return Same as {@link TimeZone#getTimeZone(String)}.
064     * @since 3.20.0
065     */
066    public static TimeZone getTimeZone(final String id) {
067        return TimeZone.getTimeZone(JAVA_25 && mapShortIDs() ? ZoneId.SHORT_IDS.getOrDefault(id, id) : id);
068    }
069
070    private static boolean mapShortIDs() {
071        return SystemProperties.getBoolean(TimeZones.class, "mapShortIDs", () -> true);
072    }
073
074    /**
075     * Returns the given TimeZone if non-{@code null}, otherwise {@link TimeZone#getDefault()}.
076     *
077     * @param timeZone a locale or {@code null}.
078     * @return the given locale if non-{@code null}, otherwise {@link TimeZone#getDefault()}.
079     * @since 3.13.0
080     */
081    public static TimeZone toTimeZone(final TimeZone timeZone) {
082        return ObjectUtils.getIfNull(timeZone, TimeZone::getDefault);
083    }
084
085    /** Do not instantiate. */
086    private TimeZones() {
087    }
088}