| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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.apache.cassandra.spark.utils; |
| |
| import java.security.SecureRandom; |
| import java.util.Calendar; |
| import java.util.TimeZone; |
| import java.util.UUID; |
| |
| import com.google.common.annotations.VisibleForTesting; |
| |
| /** |
| * This code is borrowed from the Cassandra code in {@code org.apache.cassandra.utils.TimeUUID} with slight |
| * modifications. The code was copied over to remove the dependency we had on the cassandra client library. |
| */ |
| public final class UUIDs |
| { |
| private static final long START_EPOCH = makeEpoch(); |
| private static final long CLOCK_SEQ_AND_NODE = makeClockSeqAndNode(); |
| |
| private UUIDs() |
| { |
| throw new IllegalStateException(getClass() + " is static utility class and shall not be instantiated"); |
| } |
| |
| public static UUID startOf(long timestamp) |
| { |
| return new UUID(makeMSB(fromUnixTimestamp(timestamp)), CLOCK_SEQ_AND_NODE); |
| } |
| |
| @VisibleForTesting |
| static long fromUnixTimestamp(long timestamp) |
| { |
| return (timestamp - START_EPOCH) * 10000; |
| } |
| |
| @VisibleForTesting |
| 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 calendar = Calendar.getInstance(TimeZone.getTimeZone("GMT-0")); |
| calendar.set(Calendar.YEAR, 1582); |
| calendar.set(Calendar.MONTH, Calendar.OCTOBER); |
| calendar.set(Calendar.DAY_OF_MONTH, 15); |
| calendar.set(Calendar.HOUR_OF_DAY, 0); |
| calendar.set(Calendar.MINUTE, 0); |
| calendar.set(Calendar.SECOND, 0); |
| calendar.set(Calendar.MILLISECOND, 0); |
| return calendar.getTimeInMillis(); |
| } |
| |
| private static long makeClockSeqAndNode() |
| { |
| SecureRandom secureRandom = new SecureRandom(); |
| long clock = secureRandom.nextLong(); |
| |
| long lsb = 0; |
| lsb |= 0x8000000000000000L; // Variant (2 bits) |
| lsb |= (clock & 0x0000000000003FFFL) << 48; // Clock sequence (14 bits) |
| lsb |= secureRandom.nextLong(); // 6 bytes |
| return lsb; |
| } |
| } |