OpenJDK 27 · java.rmi.server.ObjID · APIdia, the JavaDoc alternative

An ObjID is used to identify a remote object exported to an RMI runtime. When a remote object is exported, it is assigned an object identifier either implicitly or explicitly, depending on the API used to export.

The ObjID() constructor can be used to generate a unique object identifier. Such an ObjID is unique over time with respect to the host it is generated on. The ObjID(int) constructor can be used to create a "well-known" object identifier. The scope of a well-known ObjID depends on the RMI runtime it is exported to.

An ObjID instance contains an object number (of type long) and an address space identifier (of type UID). In a unique ObjID, the address space identifier is unique with respect to a given host over time. In a well-known ObjID, the address space identifier is equivalent to one returned by invoking the UID#UID(short) constructor with the value zero.

If the system property java.rmi.server.randomIDs is defined to equal the string "true" (case insensitive), then the ObjID() constructor will use a cryptographically strong random number generator to choose the object number of the returned ObjID.

Field Summary

Modifier and Type	Field and Description
public static final int	ACTIVATOR_ID Object number for well-known `ObjID` of the activator.
public static final int	DGC_ID Object number for well-known `ObjID` of the distributed garbage collector.
private static final UID	mySpace
private static final AtomicLong	nextObjNum
private final long	objNum
public static final int	REGISTRY_ID Object number for well-known `ObjID` of the registry.
private static final SecureRandom	secureRandom
private static final long	serialVersionUID indicate compatibility with JDK 1.1.x version of class
private final UID	space

Constructor Summary

Access	Constructor and Description
public	ObjID() Generates a unique object identifier.
public	ObjID(int object number for well-known object identifier objNum) Creates a "well-known" object identifier.
private	ObjID(long objNum, UID space) Constructs an object identifier given data read from a stream.

Method Summary

Modifier and Type	Method and Description
public boolean	Returns: `true` if the given object is equivalent to this one, and `false` otherwise equals(Object the object to compare this `ObjID` to obj) Overrides java.lang.Object.equals. Compares the specified object with this `ObjID` for equality.
public int	Returns: the hash code value for this object identifier hashCode() Overrides java.lang.Object.hashCode. Returns the hash code value for this object identifier, the object number.
public static ObjID	Returns: unmarshalled `ObjID` instance read(ObjectInput the `ObjectInput` instance to read `ObjID` from in) Constructs and returns a new `ObjID` instance by unmarshalling a binary representation from an `ObjectInput` instance.
public String	Returns: a string representation of this object identifier toString() Overrides java.lang.Object.toString. Returns a string representation of this object identifier.
private static boolean	useRandomIDs()
public void	write(ObjectOutput the `ObjectOutput` instance to write this `ObjID` to out) Marshals a binary representation of this `ObjID` to an `ObjectOutput` instance.

Inherited from java.lang.Object:: clone finalize getClass notify notifyAll wait wait wait

Field Detail

ACTIVATOR_ID	back to summary
public static final int ACTIVATOR_ID Object number for well-known `ObjID` of the activator.

DGC_ID	back to summary
public static final int DGC_ID Object number for well-known `ObjID` of the distributed garbage collector.

mySpace	back to summary
private static final UID mySpace

nextObjNum	back to summary
private static final AtomicLong nextObjNum

objNum	back to summary
private final long objNum See Also `hashCode`

REGISTRY_ID	back to summary
public static final int REGISTRY_ID Object number for well-known `ObjID` of the registry.

secureRandom	back to summary
private static final SecureRandom secureRandom

serialVersionUID	back to summary
private static final long serialVersionUID indicate compatibility with JDK 1.1.x version of class

space	back to summary
private final UID space

Constructor Detail

ObjID back to summary

ObjID	back to summary
public ObjID() Generates a unique object identifier. If the system property `java.rmi.server.randomIDs` is defined to equal the string `"true"` (case insensitive), then this constructor will use a cryptographically strong random number generator to choose the object number of the returned `ObjID`.

public ObjID()

Generates a unique object identifier.

If the system property java.rmi.server.randomIDs is defined to equal the string "true" (case insensitive), then this constructor will use a cryptographically strong random number generator to choose the object number of the returned ObjID.

ObjID back to summary

ObjID	back to summary
public ObjID(int objNum) Creates a "well-known" object identifier. An `ObjID` created via this constructor will not clash with any `ObjID`s generated via the no-arg constructor. Parameters objNum:int object number for well-known object identifier

public ObjID(int objNum)

Creates a "well-known" object identifier.

An ObjID created via this constructor will not clash with any ObjIDs generated via the no-arg constructor.

Parameters

objNum:int: object number for well-known object identifier

ObjID	back to summary
private ObjID(long objNum, UID space) Constructs an object identifier given data read from a stream.

Method Detail

equals back to summary

equals	back to summary
public boolean equals(Object obj) Overrides java.lang.Object.equals. Compares the specified object with this `ObjID` for equality. This method returns `true` if and only if the specified object is an `ObjID` instance with the same object number and address space identifier as this one. Parameters obj:Object the object to compare this `ObjID` to Returns:boolean `true` if the given object is equivalent to this one, and `false` otherwise

public boolean equals(Object obj)

Overrides java.lang.Object.equals.

Compares the specified object with this ObjID for equality. This method returns true if and only if the specified object is an ObjID instance with the same object number and address space identifier as this one.

Parameters

obj:Object: the object to compare this ObjID to

Returns:boolean

true if the given object is equivalent to this one, and false otherwise

hashCode	back to summary
public int hashCode() Overrides java.lang.Object.hashCode. Returns the hash code value for this object identifier, the object number. Returns:int the hash code value for this object identifier Annotations @Override

hashCode

back to summary

public int hashCode()

Overrides java.lang.Object.hashCode.

Returns the hash code value for this object identifier, the object number.

Returns:int

the hash code value for this object identifier

Annotations

@Override

read back to summary

read	back to summary
public static ObjID read(ObjectInput in) throws IOException Constructs and returns a new `ObjID` instance by unmarshalling a binary representation from an `ObjectInput` instance. Specifically, this method first invokes the given stream's `ObjectInput#readLong()` method to read an object number, then it invokes `UID#read(DataInput)` with the stream to read an address space identifier, and then it creates and returns a new `ObjID` instance that contains the object number and address space identifier that were read from the stream. Parameters in:ObjectInput the `ObjectInput` instance to read `ObjID` from Returns:ObjID unmarshalled `ObjID` instance Exceptions IOException: if an I/O error occurs while performing this operation

public static ObjID read(ObjectInput in) throws IOException

Constructs and returns a new ObjID instance by unmarshalling a binary representation from an ObjectInput instance.

Specifically, this method first invokes the given stream's ObjectInput#readLong() method to read an object number, then it invokes UID#read(DataInput) with the stream to read an address space identifier, and then it creates and returns a new ObjID instance that contains the object number and address space identifier that were read from the stream.

Parameters

in:ObjectInput: the ObjectInput instance to read ObjID from

Returns:ObjID

unmarshalled ObjID instance

Exceptions

IOException:: if an I/O error occurs while performing this operation

toString	back to summary
public String toString() Overrides java.lang.Object.toString. Returns a string representation of this object identifier. Returns:String a string representation of this object identifier

toString

back to summary

public String toString()

Overrides java.lang.Object.toString.

Returns a string representation of this object identifier.

Returns:String: a string representation of this object identifier

useRandomIDs	back to summary
private static boolean useRandomIDs()

write back to summary

write	back to summary
public void write(ObjectOutput out) throws IOException Marshals a binary representation of this `ObjID` to an `ObjectOutput` instance. Specifically, this method first invokes the given stream's `ObjectOutput#writeLong(long)` method with this object identifier's object number, and then it writes its address space identifier by invoking its `UID#write(DataOutput)` method with the stream. Parameters out:ObjectOutput the `ObjectOutput` instance to write this `ObjID` to Exceptions IOException: if an I/O error occurs while performing this operation

public void write(ObjectOutput out) throws IOException

Marshals a binary representation of this ObjID to an ObjectOutput instance.

Specifically, this method first invokes the given stream's ObjectOutput#writeLong(long) method with this object identifier's object number, and then it writes its address space identifier by invoking its UID#write(DataOutput) method with the stream.

Parameters

out:ObjectOutput: the ObjectOutput instance to write this ObjID to

Exceptions

IOException:: if an I/O error occurs while performing this operation

public final Class ObjID

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail