org.apache.commons.id.uuid.state
Class InMemoryStateImpl

java.lang.Object
  org.apache.commons.id.uuid.state.InMemoryStateImpl

All Implemented Interfaces:

java.io.Serializable, State

public class InMemoryStateImpl
extends java.lang.Object
implements State

The InMemoryStateImpl is an implementation of the State interface.

This implementation is the worst-case scenario and provides the least guarantee of no UUID duplication. This implementation is provided for systems that truly have no other means of writing to or reading from stable storage.

Version:

$Id: InMemoryStateImpl.java 480488 2006-11-29 08:57:26Z bayard $

Author:

Commons-Id team

See Also:

Serialized Form

Field Summary

Fields inherited from interface org.apache.commons.id.uuid.state.State

DEFAULT_STATE_IMPL

Constructor Summary

InMemoryStateImpl()

Method Summary

java.util.Set	getNodes() Returns the collection of Nodes for this uuid state information.
long	getSynchInterval() Returns the number of milliseconds to wait between writing to stable storage.
void	load() Method loads the Systems node identifier information usually from some stateful storage area.
void	store(java.util.Set nodesCollection) Stores the state information.
void	store(java.util.Set nodesCollection, long timestamp) Stores the state information using a predetermined timestamp.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

InMemoryStateImpl

public InMemoryStateImpl()

Method Detail

load

public void load()

Description copied from interface: State

Method loads the Systems node identifier information usually from some stateful storage area.

Note each JVM instance should have a separate configuration since a system wide Mutex is not feasible, then in a system with multiple concurrent jvm instances running - each instance should utilize a different configuration with distinct node identifiers.

Specified by:

load in interface State

See Also:

State.load()

getNodes

public java.util.Set getNodes()

Description copied from interface: State

Returns the collection of Nodes for this uuid state information.

Specified by:

getNodes in interface State

Returns:

the collection of Nodes for this uuid state.

See Also:

State.getNodes()

store

public void store(java.util.Set nodesCollection)

Description copied from interface: State

Stores the state information.

To increase the quality of the UUID uniqueness, a system that may write to stable storage SHOULD perist the state of the UUIDGenerator in order to reduce the likelihood of duplicate identifiers and increase the quality of the identifiers generated.

Specified by:

store in interface State

Parameters:

nodesCollection - a Collection of Nodes to store.

See Also:

State.store(Set)

store

public void store(java.util.Set nodesCollection,
                  long timestamp)

Description copied from interface: State

Stores the state information using a predetermined timestamp. This timestamp should be a time in the future but a shorter period than what the java virtual machine can restart within. This is normally linked to the sychInterval.

Using a point in time in the near future reduces unnecessary I/O, while allowing for the persistent state to be stored periodically, in an efficient manner.

Specified by:

store in interface State

Parameters:

nodesCollection - a Collection of Nodes to store.

timestamp - the timestamp to write all Nodes last timestamp as.

See Also:

State.store(Set, long)

getSynchInterval

public long getSynchInterval()

Description copied from interface: State

Returns the number of milliseconds to wait between writing to stable storage.

Specified by:

getSynchInterval in interface State

Returns:

the number of milliseconds to wait between writing to stable storage.

See Also:

State.getSynchInterval()