org.treeleafj.xmax.safe.ObjectId Maven / Gradle / Ivy
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package org.treeleafj.xmax.safe;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.Serializable;
import java.net.NetworkInterface;
import java.nio.BufferUnderflowException;
import java.nio.ByteBuffer;
import java.security.SecureRandom;
import java.util.Date;
import java.util.Enumeration;
import java.util.concurrent.atomic.AtomicInteger;
/**
* mongodb的objectId生成策略
*/
public final class ObjectId implements Comparable, Serializable {
private static final long serialVersionUID = 3670079982654483072L;
static final Logger LOGGER = LoggerFactory.getLogger(ObjectId.class);
private static final int LOW_ORDER_THREE_BYTES = 0x00ffffff;
private static final int MACHINE_IDENTIFIER;
private static final short PROCESS_IDENTIFIER;
private static final AtomicInteger NEXT_COUNTER = new AtomicInteger(new SecureRandom().nextInt());
private final int timestamp;
private final int machineIdentifier;
private final short processIdentifier;
private final int counter;
/**
* Gets a new object id.
*
* @return the new id
*/
public static ObjectId get() {
return new ObjectId();
}
/**
* 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;
}
/**
* Gets the generated machine identifier.
*
* @return an int representing the machine identifier
*/
public static int getGeneratedMachineIdentifier() {
return MACHINE_IDENTIFIER;
}
/**
* Gets the generated process identifier.
*
* @return the process id
*/
public static int getGeneratedProcessIdentifier() {
return PROCESS_IDENTIFIER;
}
/**
* Gets the current value of the auto-incrementing counter.
*
* @return the current counter value.
*/
public static int getCurrentCounter() {
return NEXT_COUNTER.get();
}
/**
* Creates an ObjectId using time, machine and inc values. The Java driver used to create all ObjectIds this way, but it does not
* match the ObjectId specification, which requires four values, not
* three. This major release of the Java driver conforms to the specification, but still supports clients that are relying on the
* behavior of the previous major release by providing this explicit factory method that takes three parameters instead of four.
*
*
Ordinary users of the driver will not need this method. It's only for those that have written there own BSON decoders.
*
*
NOTE: This will not break any application that use ObjectIds. The 12-byte representation will be round-trippable from old to new
* driver releases.
*
* @param time time in seconds
* @param machine machine ID
* @param inc incremental value
* @return a new {@code ObjectId} created from the given values
* @since 2.12.0
*/
public static ObjectId createFromLegacyFormat(final int time, final int machine, final int inc) {
return new ObjectId(time, machine, inc);
}
/**
* Create a new object id.
*/
public ObjectId() {
this(new Date());
}
/**
* Constructs a new instance using the given date.
*
* @param date the date
*/
public ObjectId(final Date date) {
this(dateToTimestampSeconds(date), MACHINE_IDENTIFIER, PROCESS_IDENTIFIER, NEXT_COUNTER.getAndIncrement(), 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 ObjectId(final Date date, final int counter) {
this(date, MACHINE_IDENTIFIER, PROCESS_IDENTIFIER, counter);
}
/**
* Constructs a new instances using the given date, machine identifier, process identifier, and counter.
*
* @param date the date
* @param machineIdentifier the machine identifier
* @param processIdentifier the process identifier
* @param counter the counter
* @throws IllegalArgumentException if the high order byte of machineIdentifier or counter is not zero
*/
public ObjectId(final Date date, final int machineIdentifier, final short processIdentifier, final int counter) {
this(dateToTimestampSeconds(date), machineIdentifier, processIdentifier, counter);
}
/**
* Creates an ObjectId using the given time, machine identifier, process identifier, and counter.
*
* @param timestamp the time in seconds
* @param machineIdentifier the machine identifier
* @param processIdentifier the process identifier
* @param counter the counter
* @throws IllegalArgumentException if the high order byte of machineIdentifier or counter is not zero
*/
public ObjectId(final int timestamp, final int machineIdentifier, final short processIdentifier, final int counter) {
this(timestamp, machineIdentifier, processIdentifier, counter, true);
}
private ObjectId(final int timestamp, final int machineIdentifier, final short processIdentifier, final int counter,
final boolean checkCounter) {
if ((machineIdentifier & 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.machineIdentifier = machineIdentifier;
this.processIdentifier = processIdentifier;
this.counter = counter & LOW_ORDER_THREE_BYTES;
}
/**
* Constructs a new instance from a 24-byte hexadecimal string representation.
*
* @param hexString the string to convert
* @throws IllegalArgumentException if the string is not a valid hex string representation of an ObjectId
*/
public ObjectId(final String hexString) {
this(parseHexString(hexString));
}
/**
* Constructs a new instance from the given byte array
*
* @param bytes the byte array
* @throws IllegalArgumentException if array is null or not of length 12
*/
public ObjectId(final byte[] bytes) {
if (bytes == null) {
throw new IllegalArgumentException();
}
if (bytes.length != 12) {
throw new IllegalArgumentException("need 12 bytes");
}
timestamp = makeInt(bytes[0], bytes[1], bytes[2], bytes[3]);
machineIdentifier = makeInt((byte) 0, bytes[4], bytes[5], bytes[6]);
processIdentifier = (short) makeInt((byte) 0, (byte) 0, bytes[7], bytes[8]);
counter = makeInt((byte) 0, bytes[9], bytes[10], bytes[11]);
}
/**
* Creates an ObjectId
*
* @param timestamp time in seconds
* @param machineAndProcessIdentifier machine and process identifier
* @param counter incremental value
*/
ObjectId(final int timestamp, final int machineAndProcessIdentifier, final int counter) {
this(legacyToBytes(timestamp, machineAndProcessIdentifier, counter));
}
private static byte[] legacyToBytes(final int timestamp, final int machineAndProcessIdentifier, final int counter) {
byte[] bytes = new byte[12];
bytes[0] = int3(timestamp);
bytes[1] = int2(timestamp);
bytes[2] = int1(timestamp);
bytes[3] = int0(timestamp);
bytes[4] = int3(machineAndProcessIdentifier);
bytes[5] = int2(machineAndProcessIdentifier);
bytes[6] = int1(machineAndProcessIdentifier);
bytes[7] = int0(machineAndProcessIdentifier);
bytes[8] = int3(counter);
bytes[9] = int2(counter);
bytes[10] = int1(counter);
bytes[11] = int0(counter);
return bytes;
}
/**
* Convert to a byte array. Note that the numbers are stored in big-endian order.
*
* @return the byte array
*/
public byte[] toByteArray() {
byte[] bytes = new byte[12];
bytes[0] = int3(timestamp);
bytes[1] = int2(timestamp);
bytes[2] = int1(timestamp);
bytes[3] = int0(timestamp);
bytes[4] = int2(machineIdentifier);
bytes[5] = int1(machineIdentifier);
bytes[6] = int0(machineIdentifier);
bytes[7] = short1(processIdentifier);
bytes[8] = short0(processIdentifier);
bytes[9] = int2(counter);
bytes[10] = int1(counter);
bytes[11] = int0(counter);
return bytes;
}
/**
* Gets the timestamp (number of seconds since the Unix epoch).
*
* @return the timestamp
*/
public int getTimestamp() {
return timestamp;
}
/**
* Gets the machine identifier.
*
* @return the machine identifier
*/
public int getMachineIdentifier() {
return machineIdentifier;
}
/**
* Gets the process identifier.
*
* @return the process identifier
*/
public short getProcessIdentifier() {
return processIdentifier;
}
/**
* Gets the counter.
*
* @return the counter
*/
public int getCounter() {
return counter;
}
/**
* Gets the timestamp as a {@code Date} instance.
*
* @return the Date
*/
public Date getDate() {
return new Date(timestamp * 1000L);
}
/**
* Converts this instance into a 24-byte hexadecimal string representation.
*
* @return a string representation of the ObjectId in hexadecimal format
*/
public String toHexString() {
StringBuilder buf = new StringBuilder(24);
for (final byte b : toByteArray()) {
buf.append(String.format("%02x", b & 0xff));
}
return buf.toString();
}
@Override
public boolean equals(final Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
ObjectId objectId = (ObjectId) o;
if (counter != objectId.counter) {
return false;
}
if (machineIdentifier != objectId.machineIdentifier) {
return false;
}
if (processIdentifier != objectId.processIdentifier) {
return false;
}
if (timestamp != objectId.timestamp) {
return false;
}
return true;
}
@Override
public int hashCode() {
int result = timestamp;
result = 31 * result + machineIdentifier;
result = 31 * result + (int) processIdentifier;
result = 31 * result + counter;
return result;
}
@Override
public int compareTo(final ObjectId other) {
if (other == null) {
throw new NullPointerException();
}
byte[] byteArray = toByteArray();
byte[] otherByteArray = other.toByteArray();
for (int i = 0; i < 12; i++) {
if (byteArray[i] != otherByteArray[i]) {
return ((byteArray[i] & 0xff) < (otherByteArray[i] & 0xff)) ? -1 : 1;
}
}
return 0;
}
@Override
public String toString() {
return toHexString();
}
// Deprecated methods
/**
* Gets the time of this ID, in seconds.
*
* @return the time component of this ID in seconds
* @deprecated Use #getTimestamp instead
*/
@Deprecated
public int getTimeSecond() {
return timestamp;
}
/**
* Gets the time of this instance, in milliseconds.
*
* @return the time component of this ID in milliseconds
* @deprecated Use #getDate instead
*/
@Deprecated
public long getTime() {
return timestamp * 1000L;
}
/**
* @return a string representation of the ObjectId in hexadecimal format
* @see ObjectId#toHexString()
* @deprecated use {@link #toHexString()}
*/
@Deprecated
public String toStringMongod() {
return toHexString();
}
static {
try {
MACHINE_IDENTIFIER = createMachineIdentifier();
PROCESS_IDENTIFIER = createProcessIdentifier();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
private static int createMachineIdentifier() {
// build a 2-byte machine piece based on NICs info
int machinePiece;
try {
StringBuilder sb = new StringBuilder();
Enumeration e = NetworkInterface.getNetworkInterfaces();
while (e.hasMoreElements()) {
NetworkInterface ni = e.nextElement();
sb.append(ni.toString());
byte[] mac = ni.getHardwareAddress();
if (mac != null) {
ByteBuffer bb = ByteBuffer.wrap(mac);
try {
sb.append(bb.getChar());
sb.append(bb.getChar());
sb.append(bb.getChar());
} catch (BufferUnderflowException shortHardwareAddressException) { //NOPMD
// mac with less than 6 bytes. continue
}
}
}
machinePiece = sb.toString().hashCode();
} catch (Throwable t) {
// exception sometimes happens with IBM JVM, use random
machinePiece = (new SecureRandom().nextInt());
LOGGER.warn("Failed to get machine identifier from network interface, using random number instead", t);
}
machinePiece = machinePiece & LOW_ORDER_THREE_BYTES;
return machinePiece;
}
// Creates the process identifier. This does not have to be unique per class loader because
// NEXT_COUNTER will provide the uniqueness.
private static short createProcessIdentifier() {
short processId;
try {
String processName = java.lang.management.ManagementFactory.getRuntimeMXBean().getName();
if (processName.contains("@")) {
processId = (short) Integer.parseInt(processName.substring(0, processName.indexOf('@')));
} else {
processId = (short) java.lang.management.ManagementFactory.getRuntimeMXBean().getName().hashCode();
}
} catch (Throwable t) {
processId = (short) new SecureRandom().nextInt();
LOGGER.warn("Failed to get process identifier from JMX, using random number instead", t);
}
return processId;
}
private static byte[] parseHexString(final String s) {
if (!isValid(s)) {
throw new IllegalArgumentException("invalid hexadecimal representation of an ObjectId: [" + s + "]");
}
byte[] b = new byte[12];
for (int i = 0; i < b.length; i++) {
b[i] = (byte) Integer.parseInt(s.substring(i * 2, i * 2 + 2), 16);
}
return b;
}
private static int dateToTimestampSeconds(final Date time) {
return (int) (time.getTime() / 1000);
}
// Big-Endian helpers, in this class because all other BSON numbers are little-endian
private static int makeInt(final byte b3, final byte b2, final byte b1, final byte b0) {
// CHECKSTYLE:OFF
return (((b3) << 24) |
((b2 & 0xff) << 16) |
((b1 & 0xff) << 8) |
((b0 & 0xff)));
// CHECKSTYLE:ON
}
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);
}
}