com.crankuptheamps.client

Class MemoryBookmarkStore

java.lang.Object

com.crankuptheamps.client.MemoryBookmarkStore

All Implemented Interfaces:

BookmarkStore, java.lang.AutoCloseable

public class MemoryBookmarkStore
extends java.lang.Object
implements BookmarkStore

Implements a bookmark store useful for handling server failover scenarios, but without a backing store to recover from subscriber failure. An optional RecoveryPointAdapter can be specified at construction to persist bookmark subscription recovery state to an external store so the subscription can be resumed if the subscriber fails.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	MemoryBookmarkStore.Subscription The Subscription object is used to represent internal bookmark state for the messages received and discarded on a specific subscription within the bookmark store.

Field Summary

Fields

Modifier and Type	Field and Description
protected RecoveryPointAdapter	_adapter Optional recovery point adapter used to persist bookmark replay recovery state for each subscription.
protected RecoveryPointFactory	_factory

Constructor Summary

Constructors

Constructor and Description
MemoryBookmarkStore() Initializes a new instance of the MemoryBookmarkStore class with default settings.
MemoryBookmarkStore(int targetNumberOfSubscriptions) Constructor for MemoryBookmarkStore with a target number of subscriptions.
MemoryBookmarkStore(int targetNumberOfSubscriptions, RecoveryPointAdapter adapter) Initialize self with a target number of subscriptions to pool and the specified recovery point adapter.
MemoryBookmarkStore(int targetNumberOfSubscriptions, RecoveryPointAdapter adapter, RecoveryPointFactory factory) Initialize self with a target number of subscriptions to pool and the specified recovery point adapter.

Method Summary

Modifier and Type	Method and Description
protected void	adapterUpdate(Field subId, BookmarkField bookmark) Used internally to update the RecoveryPointAdapter if there is one.
void	close() Closes down the bookmark store.
void	discard(Field subId, long bookmarkSeqNo) Discard a message based on the subscription ID and bookmark sequence number.
void	discard(Message message) Discard a message based on the provided message.
protected MemoryBookmarkStore.Subscription	find(Field subId) Finds and returns the Subscription object for the specified subscription id (subId).
Field	getMostRecent(Field subId) Get the most recent bookmark for a specific subscription.
Field	getMostRecent(Field subId, boolean useList) Get the most recent bookmark for a specific subscription.
long	getOldestBookmarkSeq(Field subId) Get the oldest bookmark sequence number for a specific subscription.
int	getServerVersion() Called by Client when connected to an AMPS server in order to retrieve the version number of the server.
boolean	isDiscarded(Message message) Check if a message is discarded based on its bookmark.
long	log(Message message) Log a message and update the bookmark sequence number.
void	persisted(Field subId, BookmarkField bookmark) Persist a bookmark for a subscription.
void	persisted(Field subId, long bookmark) Deprecated. use persisted(Field, BookmarkField) instead.
void	purge() Remove all entries in the bookmark store, completely clearing all records of messages received and discarded.
void	purge(Field subId_) Remove entries for a specific subscription ID, clearing its records of messages received and discarded.
void	setRecoveryPointFactory(RecoveryPointFactory factory_) Change the RecoveryPointFactory used by this store for its adaptor.
void	setResizeHandler(BookmarkStoreResizeHandler handler) Set the resize handler for this bookmark store and all associated subscriptions.
void	setServerVersion(int version) Set the version of the AMPS server.

Methods inherited from class java.lang.Object

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

Field Detail

_adapter

protected RecoveryPointAdapter _adapter

Optional recovery point adapter used to persist bookmark replay recovery state for each subscription.

_factory

protected RecoveryPointFactory _factory

Constructor Detail

MemoryBookmarkStore

public MemoryBookmarkStore()

Initializes a new instance of the MemoryBookmarkStore class with default settings.

MemoryBookmarkStore

public MemoryBookmarkStore(int targetNumberOfSubscriptions)

Constructor for MemoryBookmarkStore with a target number of subscriptions.

Parameters:

targetNumberOfSubscriptions - The target number of subscriptions to pre-initialize.

MemoryBookmarkStore

public MemoryBookmarkStore(int targetNumberOfSubscriptions,
                           RecoveryPointAdapter adapter)
                    throws AMPSException

Initialize self with a target number of subscriptions to pool and the specified recovery point adapter.

Parameters:

targetNumberOfSubscriptions - The number of subscriptions this store will initially create in its pool.

adapter - Recovery point adapter this instance will call with recovery point state for each of its subscriptions. The adapter can persist this state to an external store and retrieve it on application restart so that bookmark replay subscriptions can be continued approximately where they left off (with the possible delivery of some duplicate messages). The adapter will be given FixedRecoveryPoints.

Throws:

AMPSException - If the given adapter throws an exception during recovery.

MemoryBookmarkStore

public MemoryBookmarkStore(int targetNumberOfSubscriptions,
                           RecoveryPointAdapter adapter,
                           RecoveryPointFactory factory)
                    throws AMPSException

Initialize self with a target number of subscriptions to pool and the specified recovery point adapter.

Parameters:

targetNumberOfSubscriptions - The number of subscriptions this store will initially create in its pool.

adapter - Recovery point adapter this instance will call with recovery point state for each of its subscriptions. The adapter can persist this state to an external store and retrieve it on application restart so that bookmark replay subscriptions can be continued approximately where they left off (with the possible delivery of some duplicate messages).

factory - RecoveryPointFactory that will produce RecoveryPoints for the adapter.

Throws:

AMPSException - If the given adapter throws an exception during recovery.

Method Detail

setRecoveryPointFactory

public void setRecoveryPointFactory(RecoveryPointFactory factory_)
                             throws AMPSException

Change the RecoveryPointFactory used by this store for its adaptor.

Parameters:

factory_ - The new RecoveryPointFactory

Throws:

AMPSException - If the factory_ parameter is null or the recovery point adapter is null

log

public long log(Message message)
         throws AMPSException

Log a message and update the bookmark sequence number.

Specified by:

log in interface BookmarkStore

Parameters:

message - The message to log.

Returns:

The updated sequence number.

Throws:

AMPSException - If an error occurs during the log operation.

discard

public void discard(Field subId,
                    long bookmarkSeqNo)
             throws AMPSException

Discard a message based on the subscription ID and bookmark sequence number.

Specified by:

discard in interface BookmarkStore

Parameters:

subId - The subscription ID.

bookmarkSeqNo - The bookmark sequence number to discard.

Throws:

AMPSException - If an error occurs during the discard operation.

discard

public void discard(Message message)
             throws AMPSException

Discard a message based on the provided message.

Specified by:

discard in interface BookmarkStore

Parameters:

message - The message to discard.

Throws:

AMPSException - If an error occurs during the discard operation.

getMostRecent

public Field getMostRecent(Field subId)
                    throws AMPSException

Get the most recent bookmark for a specific subscription.

Specified by:

getMostRecent in interface BookmarkStore

Parameters:

subId - The subscription ID.

Returns:

The most recent bookmark.

Throws:

AMPSException - If an error occurs during the operation.

getMostRecent

public Field getMostRecent(Field subId,
                           boolean useList)
                    throws AMPSException

Get the most recent bookmark for a specific subscription.

Specified by:

getMostRecent in interface BookmarkStore

Parameters:

subId - The subscription ID.

useList - Indicates whether to use the bookmark list.

Returns:

The most recent bookmark.

Throws:

AMPSException - If an error occurs during the operation.

isDiscarded

public boolean isDiscarded(Message message)
                    throws AMPSException

Check if a message is discarded based on its bookmark.

Specified by:

isDiscarded in interface BookmarkStore

Parameters:

message - The message to check.

Returns:

True if the message is discarded, false otherwise.

Throws:

AMPSException - If an error occurs during the operation.

persisted

@Deprecated
public void persisted(Field subId,
                                  long bookmark)
                           throws AMPSException

Deprecated. use persisted(Field, BookmarkField) instead.

Old style of setting a persisted bookmark no longer used.

Specified by:

persisted in interface BookmarkStore

Parameters:

subId - The subId associated with the bookmark to be persisted.

bookmark - The bookmark to be persisted.

Throws:

AMPSException - If the bookmark was unable to be persisted to the bookmark store.

persisted

public void persisted(Field subId,
                      BookmarkField bookmark)
               throws AMPSException

Persist a bookmark for a subscription.

Specified by:

persisted in interface BookmarkStore

Parameters:

subId - The subId associated with the bookmark to be persisted.

bookmark - The bookmark to be persisted.

Throws:

AMPSException - If the bookmark was unable to be persisted to the bookmark store.

find

protected MemoryBookmarkStore.Subscription find(Field subId)

Finds and returns the Subscription object for the specified subscription id (subId).

Parameters:

subId - The subId to find or create a Subscription for.

Returns:

The Subscription for the given subId.

purge

public void purge()
           throws AMPSException

Remove all entries in the bookmark store, completely clearing all records of messages received and discarded.

Specified by:

purge in interface BookmarkStore

Throws:

AMPSException - If an error occurs during the purge operation.

purge

public void purge(Field subId_)
           throws AMPSException

Remove entries for a specific subscription ID, clearing its records of messages received and discarded.

Specified by:

purge in interface BookmarkStore

Parameters:

subId_ - The subscription ID to purge.

Throws:

AMPSException - If an error occurs during the purge operation.

getOldestBookmarkSeq

public long getOldestBookmarkSeq(Field subId)
                          throws AMPSException

Get the oldest bookmark sequence number for a specific subscription.

Specified by:

getOldestBookmarkSeq in interface BookmarkStore

Parameters:

subId - The subscription ID.

Returns:

The oldest bookmark sequence number.

Throws:

AMPSException - If an error occurs during the operation.

setResizeHandler

public void setResizeHandler(BookmarkStoreResizeHandler handler)

Set the resize handler for this bookmark store and all associated subscriptions.

Specified by:

setResizeHandler in interface BookmarkStore

Parameters:

handler - The BookmarkStoreResizeHandler to set.

setServerVersion

public void setServerVersion(int version)

Set the version of the AMPS server.

Specified by:

setServerVersion in interface BookmarkStore

Parameters:

version - The server version to set.

getServerVersion

public int getServerVersion()

Called by Client when connected to an AMPS server in order to retrieve the version number of the server. Returns retrieved version number.

Returns:

The server version, represented as an integer.

close

public void close()
           throws AMPSException

Closes down the bookmark store. If a recovery point adapter was specified during construction, this will call close() on it.

Specified by:

close in interface java.lang.AutoCloseable

Throws:

AMPSException

adapterUpdate

protected void adapterUpdate(Field subId,
                             BookmarkField bookmark)
                      throws java.io.IOException

Used internally to update the RecoveryPointAdapter if there is one.

Parameters:

subId - The subId to update.

bookmark - The latest bookmark.

Throws:

java.io.IOException - If there is an exception from the adapter.