com.crankuptheamps.client

Class DefaultBookmarkStore

java.lang.Object

com.crankuptheamps.client.DefaultBookmarkStore

All Implemented Interfaces:

BookmarkStore, java.lang.AutoCloseable

public class DefaultBookmarkStore
extends java.lang.Object
implements BookmarkStore

A no-op default implementation of the BookmarkStore interface that does nothing.

Constructor Summary

Constructors

Constructor and Description
DefaultBookmarkStore()

Method Summary

Modifier and Type	Method and Description
void	close()
void	discard(Field subId, long bookmarkSequenceNumber) You can call this when you want to mark the message specified by the subscription ID and the bookmark sequence number as discarded, indicating that the application has completed processing the message.
void	discard(Message message) You can call this when you want to mark the provided message as discarded, indicating that the application has completed processing the message.
Field	getMostRecent(Field subId) You can call this when you want to return the correct recovery point for resubscription of the provided subID from the BookmarkStore.
Field	getMostRecent(Field subId, boolean useList) You can call this when you want to return the correct recovery point for resubscription of the provided subID from the BookmarkStore.
long	getOldestBookmarkSeq(Field subId) You can call this when you want to retrieve the sequence number of the oldest bookmark in the store.
boolean	isDiscarded(Message message) Called internally by the AMPS Client.
long	log(Message message) Called internally by the AMPS Client to log a bookmark to the persistent log.
void	persisted(Field subId, BookmarkField bookmark) Called internally by the AMPS Client to record the last persisted message in the transaction log of the connected AMPS server to all of its sync replication destinations.
void	persisted(Field subId, long bookmark) Old style of setting a persisted bookmark no longer used.
void	purge() You can call this when you want to purge the contents of this store.
void	purge(Field subId_) You can call this when you want to purge the contents of this store for a given subscription ID.
void	setResizeHandler(BookmarkStoreResizeHandler handler) You can call this when you want to set a resize handler that is invoked when the store needs to resize.
void	setServerVersion(int version_) Called internally by the AMPS Client when connected to an AMPS server to indicate what version the server is.

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultBookmarkStore

public DefaultBookmarkStore()

Method Detail

log

public long log(Message message)

Description copied from interface: BookmarkStore

Called internally by the AMPS Client to log a bookmark to the persistent log.

Specified by:

log in interface BookmarkStore

Parameters:

message - The message containing the bookmark to log.

Returns:

the corresponding bookmark sequence number for this bookmark.

discard

public void discard(Field subId,
                    long bookmarkSequenceNumber)

Description copied from interface: BookmarkStore

You can call this when you want to mark the message specified by the subscription ID and the bookmark sequence number as discarded, indicating that the application has completed processing the message. Marking a message as discarded means that the message will not be replayed when the subscription resumes. Recommended to use discard(Message) instead for better performance. It is more efficient because it operates directly on a message object, eliminating the need to specify a subscription ID and bookmark sequence number separately.

Specified by:

discard in interface BookmarkStore

Parameters:

subId - The subscription ID of the bookmark.

bookmarkSequenceNumber - The bookmark sequence number.

discard

public void discard(Message message)
             throws AMPSException

Description copied from interface: BookmarkStore

You can call this when you want to mark the provided message as discarded, indicating that the application has completed processing the message. Marking a message as discarded means the message will not be replayed when the subscription resumes which helps in preventing redundant processing of messages. For optimum performance, it is critical to discard every message once its processing is complete. If a message is never discarded, it remains in the bookmark store.

Specified by:

discard in interface BookmarkStore

Parameters:

message - Message to be marked as discarded.

Throws:

AMPSException - Thrown when the specified message cannot be discarded.

getMostRecent

public Field getMostRecent(Field subId)

Description copied from interface: BookmarkStore

You can call this when you want to return the correct recovery point for resubscription of the provided subID from the BookmarkStore. This is a single bookmark or (more often) a comma-delimited list of bookmarks.

Specified by:

getMostRecent in interface BookmarkStore

Parameters:

subId - The subscription ID of the most recent bookmark.

Returns:

A Field containing the correct recovery point to use for resubscriptions.

getMostRecent

public Field getMostRecent(Field subId,
                           boolean useList)

Description copied from interface: BookmarkStore

You can call this when you want to return the correct recovery point for resubscription of the provided subID from the BookmarkStore. This is a single bookmark or (more often) a comma-delimited list of bookmarks. The useList parameter is a boolean flag. When set to true (which is the default), it affects how the recovery point is determined when the store hasn't received any persisted acknowledgments (acks). Specifically, if set to true, the method will build a list of bookmarks based on the last discarded message for each publisher. If set to false, it won't consider this additional information. This option can be useful when persisted acks are not available, allowing you to make more informed decisions about where to resume message processing.

Specified by:

getMostRecent in interface BookmarkStore

Parameters:

subId - The subscription ID of the most recent bookmark.

useList - In the case where the store has not received any persisted acks, it will build a list of bookmarks based on the last discarded for each publisher if true (default).

Returns:

A Field containing the correct recovery point to use for resubscriptions.

isDiscarded

public boolean isDiscarded(Message message)

Description copied from interface: BookmarkStore

Called internally by the AMPS Client. This method is called for each arriving message to determine if the application has already processed and discarded this message. This step is crucial to avoid processing the same message multiple times. Returns 'true' if the bookmark is in the log and marked as discarded and should therefore not be reprocessed. Otherwise, returns 'false' indicating that the message is new or hasn't been marked as discarded yet. Generally, isDiscarded is called by the AMPS Client however, there might be situations where the application needs to manually check if a message has been discarded. In such cases, the application can call this method to make that determination.

Specified by:

isDiscarded in interface BookmarkStore

Parameters:

message - Incoming message used to determine if the application has already processed and discarded the message.

Returns:

Whether the message is already in the store and marked as discarded.

purge

public void purge()
           throws AMPSException

Description copied from interface: BookmarkStore

You can call this when you want to purge the contents of this store. Removes any tracking history associated with publishers and received messages, and may delete or truncate on-disk representations as well. NOTE: This should only be called when there are no ongoing or active subscriptions (i.e. before any subscribe or after all subscriptions are unsubscribed). Purging while subscriptions are active can disrupt those processes.

Specified by:

purge in interface BookmarkStore

Throws:

AMPSException - Thrown if the store is unable to remove the contents.

purge

public void purge(Field subId_)
           throws AMPSException

Description copied from interface: BookmarkStore

You can call this when you want to purge the contents of this store for a given subscription ID. Removes any tracking history associated with publishers and received messages, and may delete or truncate on-disk representations as well. NOTE: This should only be called when the specified subscription isn't active (i.e. before it's subscribed or after it's unsubscribed). This method is more specific as compared to 'purge' method and clears data for a particular subscription identified by subId.

Specified by:

purge in interface BookmarkStore

Parameters:

subId_ - The identifier of the subscription to purge. This tells the method which subscription's data to clear.

Throws:

AMPSException - Thrown if the store is unable to remove information for the subscription.

persisted

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

Description copied from interface: BookmarkStore

Called internally by the AMPS Client to record the last persisted message in the transaction log of the connected AMPS server to all of its sync replication destinations.

Specified by:

persisted in interface BookmarkStore

Parameters:

subId - The subscription ID for the message.

bookmark - The bookmark containing the message.

Throws:

AMPSException - Thrown if the store is unable to record information in the store.

persisted

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

Description copied from interface: BookmarkStore

Old style of setting a persisted bookmark no longer used.

Specified by:

persisted in interface BookmarkStore

Parameters:

subId - The subscription ID for the message.

bookmark - The bookmark sequence number.

Throws:

AMPSException - Thrown if the store is unable to record information in the store.

getOldestBookmarkSeq

public long getOldestBookmarkSeq(Field subId)
                          throws AMPSException

Description copied from interface: BookmarkStore

You can call this when you want to retrieve the sequence number of the oldest bookmark in the store.

Specified by:

getOldestBookmarkSeq in interface BookmarkStore

Parameters:

subId - The subscription ID for the oldest bookmark in the store.

Returns:

The internal sequence number of the oldest bookmark in the store.

Throws:

AMPSException - Thrown if the operation of retrieving the oldest bookmark sequence number encounters an issue or fails.

setResizeHandler

public void setResizeHandler(BookmarkStoreResizeHandler handler)

Description copied from interface: BookmarkStore

You can call this when you want to set a resize handler that is invoked when the store needs to resize. This method allows you to set a custom function that gets called when a bookmark store needs to resize, giving you control and flexibility over how your application responds to this event.

Specified by:

setResizeHandler in interface BookmarkStore

Parameters:

handler - The handler to invoke for the resize.

setServerVersion

public void setServerVersion(int version_)

Description copied from interface: BookmarkStore

Called internally by the AMPS Client when connected to an AMPS server to indicate what version the server is. A bookmark store can modify behavior based on the version of the server.

Specified by:

setServerVersion in interface BookmarkStore

Parameters:

version_ - The version of the AMPS server.

close

public void close()

Specified by:

close in interface java.lang.AutoCloseable