com.scylladb.cdc.model.worker.TimeUUID Maven / Gradle / Ivy

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/*
 * Copyright DataStax, Inc.
 *
 * Copyright (C) 2021 ScyllaDB
 *
 * 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.scylladb.cdc.model.worker;

import java.util.Calendar;
import java.util.TimeZone;
import java.util.UUID;

// Implementation ported from Scylla Java Driver 3.x,
// UUIDs class.

class TimeUUID {
    private static final long START_EPOCH = makeEpoch();
    private static final long MIN_CLOCK_SEQ_AND_NODE = 0x8080808080808080L;
    private static final long MAX_CLOCK_SEQ_AND_NODE = 0x7f7f7f7f7f7f7f7fL;

    protected static UUID startOf(long timestamp) {
        return new UUID(makeMSB(fromUnixTimestamp(timestamp)), MIN_CLOCK_SEQ_AND_NODE);
    }

    protected static UUID endOf(long timestamp) {
        return new UUID(makeMSB(fromUnixTimestamp(timestamp + 1) - 1), MAX_CLOCK_SEQ_AND_NODE);
    }

    protected static UUID middleOf(long timestamp) {
        return new UUID(makeMSB(fromUnixTimestamp(timestamp) + 5000), 0);
    }

    private static long fromUnixTimestamp(long tstamp) {
        return (tstamp - START_EPOCH) * 10000;
    }

    private static long makeMSB(long timestamp) {
        long msb = 0L;
        msb |= (0x00000000ffffffffL & timestamp) << 32;
        msb |= (0x0000ffff00000000L & timestamp) >>> 16;
        msb |= (0x0fff000000000000L & timestamp) >>> 48;
        msb |= 0x0000000000001000L; // sets the version to 1.
        return msb;
    }

    private static long makeEpoch() {
        // UUID v1 timestamp must be in 100-nanoseconds interval since 00:00:00.000 15 Oct 1582.
        Calendar c = Calendar.getInstance(TimeZone.getTimeZone("GMT-0"));
        c.set(Calendar.YEAR, 1582);
        c.set(Calendar.MONTH, Calendar.OCTOBER);
        c.set(Calendar.DAY_OF_MONTH, 15);
        c.set(Calendar.HOUR_OF_DAY, 0);
        c.set(Calendar.MINUTE, 0);
        c.set(Calendar.SECOND, 0);
        c.set(Calendar.MILLISECOND, 0);
        return c.getTimeInMillis();
    }
}