com.facebook.util.TimeUtil.java Source code

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Here is the source code for com.facebook.util.TimeUtil.java

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/*
 * Copyright (C) 2012 Facebook, 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.facebook.util;

import com.google.common.collect.ImmutableMap;
import org.apache.log4j.Logger;
import org.joda.time.DateTime;
import org.joda.time.DateTimeUtils;
import org.joda.time.DateTimeZone;
import org.joda.time.Duration;
import org.joda.time.chrono.ISOChronology;

import java.util.Map;

public class TimeUtil {
    private static final Logger LOG = Logger.getLogger(TimeUtil.class);

    // DateTimeZone.forID() and ISOChronology.getInstance() are very expensive,
    // so we statically pre-compute a fast lookup table.
    private static final Map<String, DateTimeZone> TIME_ZONE_MAP;
    private static final Map<String, ISOChronology> CHRONOLOGY_MAP;

    static {
        ImmutableMap.Builder<String, DateTimeZone> timeZoneBuilder = new ImmutableMap.Builder<String, DateTimeZone>();
        ImmutableMap.Builder<String, ISOChronology> chronologyBuilder = new ImmutableMap.Builder<String, ISOChronology>();

        for (Object id : DateTimeZone.getAvailableIDs()) {
            String tz = (String) id;
            DateTimeZone timeZone = DateTimeZone.forID(tz);
            timeZoneBuilder.put(tz, timeZone);
            chronologyBuilder.put(tz, ISOChronology.getInstance(timeZone));
        }
        TIME_ZONE_MAP = timeZoneBuilder.build();
        CHRONOLOGY_MAP = chronologyBuilder.build();
    }

    // utility method to log how long a chunk of code takes to run
    public static <E extends Throwable> void logElapsedTime(String tag, ExtRunnable<E> task) throws E {
        long start = DateTimeUtils.currentTimeMillis();
        boolean success = false;

        try {
            task.run();
            success = true;
        } finally {
            LOG.info(String.format("%s (%b) elapsed time(ms): %d", tag, success,
                    DateTimeUtils.currentTimeMillis() - start));
        }
    }

    // utility method to log how long a chunk of code takes to run
    public static <V, E extends Throwable> V logElapsedTime(String tag, ExtCallable<V, E> task) throws E {
        long start = DateTimeUtils.currentTimeMillis();
        boolean success = false;

        try {
            V value = task.call();
            success = true;

            return value;
        } finally {
            LOG.info(String.format("%s (%b) elapsed time(ms): %d", tag, success,
                    DateTimeUtils.currentTimeMillis() - start));
        }
    }

    public static DateTimeZone getDateTimeZone(String dateTimeZoneStr) {
        if ((dateTimeZoneStr == null) || dateTimeZoneStr.isEmpty()) {
            return DateTimeZone.UTC;
        }
        return TIME_ZONE_MAP.get(dateTimeZoneStr);
    }

    public static ISOChronology getChronology(String dateTimeZoneStr) {
        if ((dateTimeZoneStr == null) || dateTimeZoneStr.isEmpty()) {
            dateTimeZoneStr = DateTimeZone.UTC.getID();
        }
        return CHRONOLOGY_MAP.get(dateTimeZoneStr);
    }

    /**
     * these methods affect only code that relies on DateTimeUtils.currentTimeMillis()
     *
     * NOTE: manipulation of {@link DateTimeUtils.currentTimeMillis()} is not thread safe
     * to begin with, so neither is this
     */
    public static void setNow(DateTime now) {
        DateTimeUtils.setCurrentMillisFixed(now.getMillis());
    }

    public static void advanceNow(Duration duration) {
        long now = DateTimeUtils.currentTimeMillis();

        DateTimeUtils.setCurrentMillisFixed(now + duration.getMillis());
    }
}