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.
static ObjectId	getSmallestWithDate(Date date)	Gets a new object id with the given date value and all other bits zeroed.
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

getSmallestWithDate

public static ObjectId getSmallestWithDate(Date date)

Gets a new object id with the given date value and all other bits zeroed.

The returned object id will compare as less than or equal to any other object id within the same second as the given date, and less than any later date.

Parameters:

date - the date

Returns:

the ObjectId

Since:

4.1

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