Package org.bson.types

Class ObjectId

java.lang.Object

org.bson.types.ObjectId

All Implemented Interfaces:

Serializable, Comparable<ObjectId>

public final class ObjectId
extends Object
implements Comparable<ObjectId>, Serializable

A globally unique identifier for objects.

Consists of 12 bytes, divided as follows:

ObjectID layout

0	1	2	3	4	5	6	7	8	9	10	11
time				random value					inc

Instances of this class are immutable.

See Also:

Serialized Form

MongoDB documentation

ObjectId

Constructor Summary

Constructors

Constructor	Description
ObjectId()	Create a new object id.
ObjectId(byte[] bytes)	Constructs a new instance from the given byte array
ObjectId(int timestamp, int counter)	Creates an ObjectId using the given time, machine identifier, process identifier, and counter.
ObjectId(String hexString)	Constructs a new instance from a 24-byte hexadecimal string representation.
ObjectId(ByteBuffer buffer)	Constructs a new instance from the given ByteBuffer
ObjectId(Date date)	Constructs a new instance using the given date.
ObjectId(Date date, int counter)	Constructs a new instances using the given date and counter.

Method Summary

Modifier and Type	Method	Description
int	compareTo(ObjectId other)
boolean	equals(Object o)
static ObjectId	get()	Gets a new object id.
Date	getDate()	Gets the timestamp as a Date instance.
int	getTimestamp()	Gets the timestamp (number of seconds since the Unix epoch).
int	hashCode()
static boolean	isValid(String hexString)	Checks if a string could be an ObjectId.
void	putToByteBuffer(ByteBuffer buffer)	Convert to bytes and put those bytes to the provided ByteBuffer.
byte[]	toByteArray()	Convert to a byte array.
String	toHexString()	Converts this instance into a 24-byte hexadecimal string representation.
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ObjectId

public ObjectId()

Create a new object id.

ObjectId

public ObjectId(Date date)

Constructs a new instance using the given date.

Parameters:

date - the date

ObjectId

public ObjectId(Date date,
                int counter)

Constructs a new instances using the given date and counter.

Parameters:

date - the date

counter - the counter

Throws:

IllegalArgumentException - if the high order byte of counter is not zero

ObjectId

public ObjectId(int timestamp,
                int counter)

Creates an ObjectId using the given time, machine identifier, process identifier, and counter.

Parameters:

timestamp - the time in seconds

counter - the counter

Throws:

IllegalArgumentException - if the high order byte of counter is not zero

ObjectId

public ObjectId(String hexString)

Constructs a new instance from a 24-byte hexadecimal string representation.

Parameters:

hexString - the string to convert

Throws:

IllegalArgumentException - if the string is not a valid hex string representation of an ObjectId

ObjectId

public ObjectId(byte[] bytes)

Constructs a new instance from the given byte array

Parameters:

bytes - the byte array

Throws:

IllegalArgumentException - if array is null or not of length 12

ObjectId

public ObjectId(ByteBuffer buffer)

Constructs a new instance from the given ByteBuffer

Parameters:

buffer - the ByteBuffer

Throws:

IllegalArgumentException - if the buffer is null or does not have at least 12 bytes remaining

Since:

3.4

Method Detail

get

public static ObjectId get()

Gets a new object id.

Returns:

the new id

isValid

public static boolean isValid(String hexString)

Checks if a string could be an ObjectId.

Parameters:

hexString - a potential ObjectId as a String.

Returns:

whether the string could be an object id

Throws:

IllegalArgumentException - if hexString is null

toByteArray

public byte[] toByteArray()

Convert to a byte array. Note that the numbers are stored in big-endian order.

Returns:

the byte array

putToByteBuffer

public void putToByteBuffer(ByteBuffer buffer)

Convert to bytes and put those bytes to the provided ByteBuffer. Note that the numbers are stored in big-endian order.

Parameters:

buffer - the ByteBuffer

Throws:

IllegalArgumentException - if the buffer is null or does not have at least 12 bytes remaining

Since:

3.4

getTimestamp

public int getTimestamp()

Gets the timestamp (number of seconds since the Unix epoch).

Returns:

the timestamp

getDate

public Date getDate()

Gets the timestamp as a Date instance.

Returns:

the Date

toHexString

public String toHexString()

Converts this instance into a 24-byte hexadecimal string representation.

Returns:

a string representation of the ObjectId in hexadecimal format

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

compareTo

public int compareTo(ObjectId other)

Specified by:

compareTo in interface Comparable<ObjectId>

toString

public String toString()

Overrides:

toString in class Object