com.crankuptheamps.client

Class LoggedBookmarkStore.Subscription

java.lang.Object

com.crankuptheamps.client.LoggedBookmarkStore.Subscription

All Implemented Interfaces:

Subscription

Enclosing class:

LoggedBookmarkStore

protected static class LoggedBookmarkStore.Subscription
extends java.lang.Object
implements 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 java.lang.String	_recoveryTimestamp The last-modified timestamp of the backing bookmark log file, just before recovery is initiated.

Constructor Summary

Constructors

Constructor and Description
Subscription()

Method Summary

Modifier and Type	Method and Description
void	discard(long index) Discards an entry in the bookmark ring buffer and updates the status accordingly.
Field	getLastPersisted() Retrieves the last persisted bookmark
Field	getMostRecent() Retrieves the most recent bookmark.
protected Field	getMostRecent(boolean updateRecovery_) Retrieves the most recent bookmark with an option to update recovery status.
Field	getMostRecentList(boolean useList)
long	getOldestBookmarkSeq() Retrieves the sequence number of the oldest bookmark in the subscription's bookmark ring buffer.
BookmarkRangeField	getRange() Retrieves the current bookmark range.
java.lang.String	getRecoveryTimestamp() Get the recovery timestamp associated with this message.
void	init(Field subscriptionId, LoggedBookmarkStore parent) Initializes the subscription with the given subscription ID and the parent LoggedBookmarkStore.
boolean	isDiscarded(BookmarkField bookmark) Check to see if this message is older than the most recent one seen, and if it is, then check to see if it is discarded.
boolean	justRecovered() Call on a Subscription object just after recovery is performed to convert logged entries into recovery entries and set the publishers cache state to the earliest sequence seen for each publisher minus one.
long	log(BookmarkField bookmark) This is a method the Client calls and is not for customer user.
void	reset() Reset the state of this subscription object such that it can be returned to the pool for reuse.
void	setLastPersisted(BookmarkField bookmark) Sets the last persisted bookmark using a provided BookmarkField object.
void	setLastPersisted(long bookmark) Deprecated. Use setLastPersisted(BookmarkField) instead.
static void	setPublishersToDiscarded(java.util.List<BookmarkRingBuffer.Entry> active, java.util.Map<java.lang.Long,java.lang.Long> publishers) Update the provided publishers map with the highest sequence number that has been discarded for each publisher based on the given list of active bookmark entries.
protected void	setRecoveryTimestamp(java.lang.String rts) Sets the recovery timestamp associated with this message.
void	setResizeHandler(BookmarkStoreResizeHandler handler, BookmarkStore store) Sets the resize handler for the bookmark store.

Methods inherited from class java.lang.Object

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

Field Detail

_recoveryTimestamp

protected volatile java.lang.String _recoveryTimestamp

The last-modified timestamp of the backing bookmark log file, just before recovery is initiated. When this is not null we intend to include it in the list of bookmarks returned by getMostRecentList() until a message is discarded on the sub or the sub state is purged. Originally we thought the recovery timestamp could be stored as the last-persisted for each recovered sub, but it must be stored separately here because setting it as a sub's last-persisted could cause us to lose a persisted ack that is earlier than the backing file's last-modified time.

Constructor Detail

Subscription

public Subscription()

Method Detail

reset

public void reset()

Reset the state of this subscription object such that it can be returned to the pool for reuse. This method clears all internal data structures and sets necessary attributes to their initial values. This helps manage file size and resource usage efficiently.

init

public void init(Field subscriptionId,
                 LoggedBookmarkStore parent)

Initializes the subscription with the given subscription ID and the parent LoggedBookmarkStore. This method sets up the initial state of the subscription, including associating it with a specific store.

Parameters:

subscriptionId - The ID of the subscription to initialize.

parent - The parent LoggedBookmarkStore to associate with this subscription.

getRecoveryTimestamp

public java.lang.String getRecoveryTimestamp()

Get the recovery timestamp associated with this message. The recovery timestamp represents the time at which the message was recovered by the client during a resubscription after a disconnection. This timestamp provides information about when the message was originally published or received by the server.

Returns:

The recovery timestamp as a string in a format that represents the time and date when the message was recovered by the client.

setRecoveryTimestamp

protected final void setRecoveryTimestamp(java.lang.String rts)

Sets the recovery timestamp associated with this message.

Parameters:

rts - The recovery timestamp to be set.

log

public long log(BookmarkField bookmark)
         throws java.io.IOException,
                CommandException

This is a method the Client calls and is not for customer user. Logs a bookmark into the subscription. If the bookmark is a range, it processes the range accordingly.

Specified by:

log in interface Subscription

Parameters:

bookmark - The bookmark to log.

Returns:

The sequence number associated with the logged bookmark or 0 if no bookmark was logged.

Throws:

java.io.IOException - If there is an I/O error during logging.

CommandException - Thrown when an invalid bookmark range is specified.

discard

public void discard(long index)
             throws java.io.IOException

Discards an entry in the bookmark ring buffer and updates the status accordingly.

Specified by:

discard in interface Subscription

Parameters:

index - The index of the entry to discard.

Throws:

java.io.IOException - If there is an I/O error during the discard operation.

isDiscarded

public boolean isDiscarded(BookmarkField bookmark)
                    throws java.io.IOException

Check to see if this message is older than the most recent one seen, and if it is, then check to see if it is discarded.

Specified by:

isDiscarded in interface Subscription

Parameters:

bookmark - The bookmark to check for discard status.

Returns:

True if the message is discarded, false otherwise.

Throws:

java.io.IOException - If there is an I/O error during the check.

getLastPersisted

public Field getLastPersisted()

Retrieves the last persisted bookmark

Returns:

The last persisted bookmark.

getRange

public BookmarkRangeField getRange()

Retrieves the current bookmark range.

Specified by:

getRange in interface Subscription

Returns:

The current bookmark range.

getMostRecent

public Field getMostRecent()

Retrieves the most recent bookmark.

Specified by:

getMostRecent in interface Subscription

Returns:

The most recent bookmark.

getMostRecent

protected Field getMostRecent(boolean updateRecovery_)

Retrieves the most recent bookmark with an option to update recovery status.

Parameters:

updateRecovery_ - Whether to update the recovery status before retrieving the most recent bookmark.

Returns:

The most recent bookmark.

getMostRecentList

public Field getMostRecentList(boolean useList)

Specified by:

getMostRecentList in interface Subscription

setLastPersisted

@Deprecated
public void setLastPersisted(long bookmark)
                                  throws java.io.IOException

Deprecated. Use setLastPersisted(BookmarkField) instead.

[DEPRECATED] Sets the last persisted bookmark using the old style of specifying the bookmark as a sequence number.

Specified by:

setLastPersisted in interface Subscription

Parameters:

bookmark - The sequence number of the bookmark (no longer used).

Throws:

java.io.IOException - If an I/O error occurs.

setLastPersisted

public void setLastPersisted(BookmarkField bookmark)
                      throws java.io.IOException

Sets the last persisted bookmark using a provided BookmarkField object. This method updates the internal state and writes the persisted bookmark to the parent with appropriate handling.

Specified by:

setLastPersisted in interface Subscription

Parameters:

bookmark - The BookmarkField object representing the last persisted bookmark.

Throws:

java.io.IOException - If an I/O error occurs.

getOldestBookmarkSeq

public long getOldestBookmarkSeq()

Retrieves the sequence number of the oldest bookmark in the subscription's bookmark ring buffer. This represents the starting point of the subscription.

Specified by:

getOldestBookmarkSeq in interface Subscription

Returns:

The sequence number of the oldest bookmark in the ring buffer.

justRecovered

public boolean justRecovered()

Call on a Subscription object just after recovery is performed to convert logged entries into recovery entries and set the publishers cache state to the earliest sequence seen for each publisher minus one. NOTE: If after recovery lastDiscarded for this sub is null (i.e. nothing was discarded) and lastPersisted is null or EPOCH (i.e. no persisted ack was recorded in the log), then we can throw away this subscription state and return this Subscription object to the pool.

Returns:

Indicates whether this subscription's state was reset (because it's unneeded due to the lack of any discards and persisted acks) and this object should be returned to the Subscription pool.

setPublishersToDiscarded

public static void setPublishersToDiscarded(java.util.List<BookmarkRingBuffer.Entry> active,
                                            java.util.Map<java.lang.Long,java.lang.Long> publishers)

Update the provided publishers map with the highest sequence number that has been discarded for each publisher based on the given list of active bookmark entries.

Parameters:

active - A list of active bookmark entries to consider for updating the publishers' highest discarded sequence numbers.

publishers - A map that associates publisher IDs with their highest discarded sequence numbers. This map will be updated with the latest discarded sequence numbers for each publisher.

setResizeHandler

public void setResizeHandler(BookmarkStoreResizeHandler handler,
                             BookmarkStore store)

Sets the resize handler for the bookmark store. The resize handler is responsible for managing file size when the bookmark store needs to be resized.

Specified by:

setResizeHandler in interface Subscription

Parameters:

handler - The `BookmarkStoreResizeHandler` responsible for handling file size management.

store - The `BookmarkStore` associated with the resize handler.