- All Implemented Interfaces:
Serializable
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(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.
- Since:
- 1.1
- See Also:
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic final intObject number for well-knownObjIDof the activator.static final intObject number for well-knownObjIDof the distributed garbage collector.static final intObject number for well-knownObjIDof the registry. -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionbooleanCompares the specified object with thisObjIDfor equality.inthashCode()Returns the hash code value for this object identifier, the object number.static ObjIDread(ObjectInput in) Constructs and returns a newObjIDinstance by unmarshalling a binary representation from anObjectInputinstance.toString()Returns a string representation of this object identifier.voidwrite(ObjectOutput out) Marshals a binary representation of thisObjIDto anObjectOutputinstance.
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Field Details
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REGISTRY_ID
public static final int REGISTRY_IDObject number for well-knownObjIDof the registry.- See Also:
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ACTIVATOR_ID
public static final int ACTIVATOR_IDObject number for well-knownObjIDof the activator.- See Also:
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DGC_ID
public static final int DGC_IDObject number for well-knownObjIDof the distributed garbage collector.- See Also:
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Constructor Details
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ObjID
public ObjID()Generates a unique object identifier.If the system property
java.rmi.server.randomIDsis 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 returnedObjID. -
ObjID
public ObjID(int objNum) Creates a "well-known" object identifier.An
ObjIDcreated via this constructor will not clash with anyObjIDs generated via the no-arg constructor.- Parameters:
objNum- object number for well-known object identifier
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Method Details
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write
Marshals a binary representation of thisObjIDto anObjectOutputinstance.Specifically, this method first invokes the given stream's
DataOutput.writeLong(long)method with this object identifier's object number, and then it writes its address space identifier by invoking itsUID.write(DataOutput)method with the stream.- Parameters:
out- theObjectOutputinstance to write thisObjIDto- Throws:
IOException- if an I/O error occurs while performing this operation
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read
Constructs and returns a newObjIDinstance by unmarshalling a binary representation from anObjectInputinstance.Specifically, this method first invokes the given stream's
DataInput.readLong()method to read an object number, then it invokesUID.read(DataInput)with the stream to read an address space identifier, and then it creates and returns a newObjIDinstance that contains the object number and address space identifier that were read from the stream.- Parameters:
in- theObjectInputinstance to readObjIDfrom- Returns:
- unmarshalled
ObjIDinstance - Throws:
IOException- if an I/O error occurs while performing this operation
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hashCode
public int hashCode()Returns the hash code value for this object identifier, the object number. -
equals
Compares the specified object with thisObjIDfor equality. This method returnstrueif and only if the specified object is anObjIDinstance with the same object number and address space identifier as this one. -
toString
Returns a string representation of this object identifier.
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