com.fizzed.crux.util.TimeUUID Maven / Gradle / Ivy
/*
* Copyright 2018 Fizzed, 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.fizzed.crux.util;
import java.io.Serializable;
import java.util.Arrays;
import java.util.UUID;
/**
* A time-based UUID that is internally stored in a sortable/lexicographical
* byte ordering. It's outside appearance (e.g. toString()) is identical as
* java.util.UUID, but you can access its underlying byte array, and its
* natural ordering will be time ascending. Very useful for storing in databases
* as binary and then have it ordered as time ascending if in an indexed column.
*
* @author jjlauer
*/
public class TimeUUID implements Serializable, Comparable {
private final byte[] timeBytes;
public TimeUUID(byte[] timeBytes) {
this.timeBytes = timeBytes;
}
public byte[] getBytes() {
return this.timeBytes;
}
public long getEpochMillis() {
return UUIDs.getEpochMillis(this.toUUID());
}
public UUID toUUID() {
return UUIDs.fromTimeBytes(this.timeBytes);
}
static public TimeUUID fromUUID(UUID uuid) {
return new TimeUUID(UUIDs.toTimeBytes(uuid));
}
static public TimeUUID fromString(String uuid) {
return fromUUID(UUID.fromString(uuid));
}
@Override
public String toString() {
return this.toUUID().toString();
}
@Override
public int hashCode() {
int hash = 7;
hash = 61 * hash + Arrays.hashCode(this.timeBytes);
return hash;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
final TimeUUID other = (TimeUUID) obj;
return Arrays.equals(this.timeBytes, other.timeBytes);
}
/**
* Compares this TimeUUID with the specified TimeUUID. Since a TimeUUID
* is already arranged in a sortable byte-order, this method simply compares
* timeBytes left to right.
* @param val {@code TimeUUID} to which this {@code TimeUUID} is to be compared
* @return -1, 0 or 1 as this {@code TimeUUID} is less than, equal to, or
* greater than {@code val}
*/
@Override
public int compareTo(TimeUUID val) {
int c;
for (int i = 0; i < timeBytes.length; i++) {
// unsigned comparison is critical
c = Byte.toUnsignedInt(timeBytes[i]) - Byte.toUnsignedInt(val.timeBytes[i]);
if (c < 0) {
return -1;
} else if (c > 0) {
return 1;
}
}
return 0;
}
}