org.hd.d.pg2k.svrCore.vars
Class InstanceID

java.lang.Object
  org.hd.d.pg2k.svrCore.vars.InstanceID

All Implemented Interfaces:

java.io.ObjectInputValidation, java.io.Serializable, java.lang.Comparable<InstanceID>, MemoryTools.Internable

public final class InstanceID
extends java.lang.Object
implements java.io.Serializable, java.io.ObjectInputValidation, MemoryTools.Internable, java.lang.Comparable<InstanceID>

Immutable globally-unique instance ID for a JVM participating in a set of SystemVariables. This is the key to a globalmap variable, and each participating system should have just one such value, probably generated by a data pipeline endpoint.

Internally, this is a randomly-generated (non-negative) long value.

See Also:

Serialized Form

ID

private final long ID

Unique (positive) long ID from a cryptographically-good random-number source.

serialVersionUID

private static final long serialVersionUID

Unique Serialisation class ID generated by http://random.hd.org/.

See Also:

Constant Field Values

InstanceID

private InstanceID()

Create a new instance with a new/unique ID from a cryptographically-good random-number source.

createInstanceID

public static InstanceID createInstanceID()

Create a new, unique instance ID; never null. This is immediately intern()ed so that there will never be more than one copy of each unique InstanceID in memory at any one time (except transiently during deserialisation).

longValue

public long longValue()

Long representation of ID; non-negative.

toString

public java.lang.String toString()

String representation of ID as a non-negative base-36 number.

Overrides:

toString in class java.lang.Object

compareTo

public int compareTo(InstanceID other)

Comparable ordering is on ID value alone in numeric ID order.

Specified by:

compareTo in interface java.lang.Comparable<InstanceID>

equals

public boolean equals(java.lang.Object obj)

Equality is based on the whole ID. But in fact due to instance control we can in fact use == at least as an optimisation!

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

The hash is derived from the ID. This implementation just uses the hash of the name.

Overrides:

hashCode in class java.lang.Object

readResolve

protected java.lang.Object readResolve()
                                throws java.io.ObjectStreamException

Deserialise: validate and eliminate duplicates coming off the wire. Ensures that there is never more than one copy of any given InstanceID value in memory (other than transiently).

Returns:

identical, de-duped, non-null instance

Throws:

java.io.ObjectStreamException

validateObject

public void validateObject()
                    throws java.io.InvalidObjectException

Check for legal state.

Specified by:

validateObject in interface java.io.ObjectInputValidation

Throws:

java.io.InvalidObjectException