com.bluenimble.platform.OID Maven / Gradle / Ivy
package com.bluenimble.platform;
import java.io.Serializable;
import java.nio.ByteBuffer;
import java.security.SecureRandom;
import java.util.Date;
import java.util.concurrent.atomic.AtomicInteger;
public final class OID implements Serializable {
private static final long serialVersionUID = 3670079982654483072L;
private static final int OBJECT_ID_LENGTH = 12;
private static final int LOW_ORDER_THREE_BYTES = 0x00ffffff;
// Use primitives to represent the 5-byte random value.
private static final int RANDOM_VALUE1;
private static final short RANDOM_VALUE2;
private static final AtomicInteger NEXT_COUNTER = new AtomicInteger(new SecureRandom().nextInt());
private static final char[] HEX_CHARS = new char[] {
'0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
private final int timestamp;
private final int counter;
private final int randomValue1;
private final short randomValue2;
public static OID get () {
return new OID ();
}
public OID () {
this (new Date ());
}
/**
* Checks if a string could be an {@code ObjectId}.
*
* @param hexString a potential ObjectId as a String.
* @return whether the string could be an object id
* @throws IllegalArgumentException if hexString is null
*/
public static boolean isValid(final String hexString) {
if (hexString == null) {
throw new IllegalArgumentException();
}
int len = hexString.length();
if (len != 24) {
return false;
}
for (int i = 0; i < len; i++) {
char c = hexString.charAt(i);
if (c >= '0' && c <= '9') {
continue;
}
if (c >= 'a' && c <= 'f') {
continue;
}
if (c >= 'A' && c <= 'F') {
continue;
}
return false;
}
return true;
}
/**
* Constructs a new instance using the given date.
*
* @param date the date
*/
public OID(final Date date) {
this(dateToTimestampSeconds(date), NEXT_COUNTER.getAndIncrement() & LOW_ORDER_THREE_BYTES, false);
}
/**
* Constructs a new instances using the given date and counter.
*
* @param date the date
* @param counter the counter
* @throws IllegalArgumentException if the high order byte of counter is not zero
*/
public OID(final Date date, final int counter) {
this(dateToTimestampSeconds(date), counter, true);
}
/**
* Creates an ObjectId using the given time, machine identifier, process identifier, and counter.
*
* @param timestamp the time in seconds
* @param counter the counter
* @throws IllegalArgumentException if the high order byte of counter is not zero
*/
public OID(final int timestamp, final int counter) {
this(timestamp, counter, true);
}
private OID(final int timestamp, final int counter, final boolean checkCounter) {
this(timestamp, RANDOM_VALUE1, RANDOM_VALUE2, counter, checkCounter);
}
private OID(final int timestamp, final int randomValue1, final short randomValue2, final int counter,
final boolean checkCounter) {
if ((randomValue1 & 0xff000000) != 0) {
throw new IllegalArgumentException("The machine identifier must be between 0 and 16777215 (it must fit in three bytes).");
}
if (checkCounter && ((counter & 0xff000000) != 0)) {
throw new IllegalArgumentException("The counter must be between 0 and 16777215 (it must fit in three bytes).");
}
this.timestamp = timestamp;
this.counter = counter & LOW_ORDER_THREE_BYTES;
this.randomValue1 = randomValue1;
this.randomValue2 = randomValue2;
}
/**
* Convert to a byte array. Note that the numbers are stored in big-endian order.
*
* @return the byte array
*/
public byte[] toByteArray() {
ByteBuffer buffer = ByteBuffer.allocate(OBJECT_ID_LENGTH);
putToByteBuffer(buffer);
return buffer.array(); // using .allocate ensures there is a backing array that can be returned
}
/**
* Convert to bytes and put those bytes to the provided ByteBuffer.
* Note that the numbers are stored in big-endian order.
*
* @param buffer the ByteBuffer
* @throws IllegalArgumentException if the buffer is null or does not have at least 12 bytes remaining
* @since 3.4
*/
public void putToByteBuffer(final ByteBuffer buffer) {
buffer.put(int3(timestamp));
buffer.put(int2(timestamp));
buffer.put(int1(timestamp));
buffer.put(int0(timestamp));
buffer.put(int2(randomValue1));
buffer.put(int1(randomValue1));
buffer.put(int0(randomValue1));
buffer.put(short1(randomValue2));
buffer.put(short0(randomValue2));
buffer.put(int2(counter));
buffer.put(int1(counter));
buffer.put(int0(counter));
}
/**
* Gets the timestamp (number of seconds since the Unix epoch).
*
* @return the timestamp
*/
public int getTimestamp() {
return timestamp;
}
/**
* Gets the timestamp as a {@code Date} instance.
*
* @return the Date
*/
public Date getDate() {
return new Date((timestamp & 0xFFFFFFFFL) * 1000L);
}
/**
* Converts this instance into a 24-byte hexadecimal string representation.
*
* @return a string representation of the ObjectId in hexadecimal format
*/
public String toHexString() {
char[] chars = new char[OBJECT_ID_LENGTH * 2];
int i = 0;
for (byte b : toByteArray()) {
chars[i++] = HEX_CHARS[b >> 4 & 0xF];
chars[i++] = HEX_CHARS[b & 0xF];
}
return new String(chars);
}
@Override
public String toString() {
return toHexString();
}
static {
try {
SecureRandom secureRandom = new SecureRandom();
RANDOM_VALUE1 = secureRandom.nextInt(0x01000000);
RANDOM_VALUE2 = (short) secureRandom.nextInt(0x00008000);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
private static int dateToTimestampSeconds(final Date time) {
return (int) (time.getTime() / 1000);
}
private static byte int3(final int x) {
return (byte) (x >> 24);
}
private static byte int2(final int x) {
return (byte) (x >> 16);
}
private static byte int1(final int x) {
return (byte) (x >> 8);
}
private static byte int0(final int x) {
return (byte) (x);
}
private static byte short1(final short x) {
return (byte) (x >> 8);
}
private static byte short0(final short x) {
return (byte) (x);
}
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