com.crankuptheamps.client

Class BlockPublishStore

java.lang.Object

com.crankuptheamps.client.BlockPublishStore

All Implemented Interfaces:

Store, java.lang.AutoCloseable

Direct Known Subclasses:

MemoryPublishStore, PublishStore

public class BlockPublishStore
extends java.lang.Object
implements Store

BlockPublishStore is a base class for publish Store implementations. As messages are stored, space is allocated from a pre-created flat buffer. As messages are discarded, space in that buffer is marked "free" for future store operations. If messages are stored faster than they are published, the buffer is re-sized to create more capacity.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	BlockPublishStore.Buffer Interface which is used to hold the BlockPublishStore buffer data.
static class	BlockPublishStore.ByteSequence A simple wrapper object around a byte array that allows a sub-range to be specified using its offset and length properties.

Nested classes/interfaces inherited from interface com.crankuptheamps.client.Store

Store.StoreReplayer

Field Summary

Fields

Modifier and Type	Field and Description
protected BlockPublishStore.Buffer	_buffer
protected boolean	_errorOnPublishGap
protected PublishStoreResizeHandler	_resizeHandler
protected static int	AMPS_MIN_PUB_STORE_DISCARDED_VERSION
protected static int	METADATA_LAST_DISCARDED_LOCATION
protected static int	METADATA_VERSION_LOCATION

Fields inherited from interface com.crankuptheamps.client.Store

SOWDeleteByBookmark, SOWDeleteByBookmarkCancel, SOWDeleteByData, SOWDeleteByFilter, SOWDeleteByKeys

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	BlockPublishStore(BlockPublishStore.Buffer buffer) Protected constructor for BlockPublishStore.
protected	BlockPublishStore(BlockPublishStore.Buffer buffer, int blocksPerRealloc) Protected constructor for BlockPublishStore.
protected	BlockPublishStore(BlockPublishStore.Buffer buffer, int blocksPerRealloc, boolean isAFile) Protected constructor for BlockPublishStore.

Method Summary

Modifier and Type	Method and Description
void	close() Closes the BlockPublishStore.
void	discardUpTo(long index) This method is responsible for managing the discarding of blocks in a store based on the specified index.
void	flush() Flushes the publish store.
void	flush(long timeout) Flushes the publish store, waiting until all messages in the store are flushed or until a timeout occurs.
boolean	getErrorOnPublishGap() Get whether the Store will throw a PublishGapException from discardUpTo if the sequence number being discarded is less then the current last persisted.
long	getHighestUnpersisted() Gets the highest unpersisted sequence number.
long	getLastPersisted() Gets the last persisted sequence number.
long	getLowestUnpersisted() Gets the lowest unpersisted sequence number.
protected void	growFreeListIfEmpty() Ensures that the free list is not empty by potentially growing it.
protected void	recover() Recovers the store's state during initialization.
void	replay(Store.StoreReplayer replayer) Replays stored messages onto a store replayer.
boolean	replaySingle(Store.StoreReplayer replayer, long index) Replays a single message from the store, given a specific sequence index, onto a store replayer.
void	setErrorOnPublishGap(boolean errorOnGap) Set whether the Store should throw a PublishGapException from discardUpTo if the sequence number being discarded is less then the current last persisted.
void	setMessage(Message m) Sets the message to be stored.
void	setResizeHandler(PublishStoreResizeHandler handler) Sets a resize handler for the publish store.
void	store(Message m) Stores a message in the BlockPublishStore.
protected void	store(Message m, boolean assignSequence) Protected utility method for storing messages in the BlockPublishStore.
long	unpersistedCount() Returns the count of unpersisted messages in the store.

Methods inherited from class java.lang.Object

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

Field Detail

_resizeHandler

protected PublishStoreResizeHandler _resizeHandler

_buffer

protected BlockPublishStore.Buffer _buffer

_errorOnPublishGap

protected boolean _errorOnPublishGap

AMPS_MIN_PUB_STORE_DISCARDED_VERSION

protected static final int AMPS_MIN_PUB_STORE_DISCARDED_VERSION

See Also:

Constant Field Values

METADATA_VERSION_LOCATION

protected static final int METADATA_VERSION_LOCATION

See Also:

Constant Field Values

METADATA_LAST_DISCARDED_LOCATION

protected static final int METADATA_LAST_DISCARDED_LOCATION

See Also:

Constant Field Values

Constructor Detail

BlockPublishStore

protected BlockPublishStore(BlockPublishStore.Buffer buffer,
                            int blocksPerRealloc,
                            boolean isAFile)

Protected constructor for BlockPublishStore. This constructor initializes the BlockPublishStore with a specified buffer and blocksPerRealloc

Parameters:

buffer - An instance of the Buffer interface representing the data buffer.

blocksPerRealloc - An integer representing the number of blocks per reallocation.

isAFile - A boolean indicating whether this store represents a file.

BlockPublishStore

protected BlockPublishStore(BlockPublishStore.Buffer buffer,
                            int blocksPerRealloc)

Protected constructor for BlockPublishStore. This constructor is a convenience method that calls the first constructor with isAFile set to false

Parameters:

buffer - An instance of the Buffer interface representing the data buffer.

blocksPerRealloc - An integer representing the number of blocks per reallocation.

BlockPublishStore

protected BlockPublishStore(BlockPublishStore.Buffer buffer)

Protected constructor for BlockPublishStore. This constructor is a convenience method that calls the second constructor with default blocksPerRealloc (10000) and isAFile (false).

Parameters:

buffer - An instance of the Buffer interface representing the data buffer.

Method Detail

store

public void store(Message m)
           throws StoreException

Stores a message in the BlockPublishStore.

Specified by:

store in interface Store

Parameters:

m - The message to be stored.

Throws:

StoreException - If an error occurs during message storage.

close

public void close()
           throws java.lang.Exception

Closes the BlockPublishStore.

Specified by:

close in interface java.lang.AutoCloseable

Throws:

java.lang.Exception - If an error occurs during the closing operation.

store

protected void store(Message m,
                     boolean assignSequence)
              throws StoreException

Protected utility method for storing messages in the BlockPublishStore.

Parameters:

m - The message to be stored.

assignSequence - A boolean flag indicating whether to assign a sequence number to the message.

Throws:

StoreException - If an error occurs during message storage.

discardUpTo

public void discardUpTo(long index)
                 throws StoreException

This method is responsible for managing the discarding of blocks in a store based on the specified index. It handles locking, updating metadata, and organizing the blocks for efficient reuse.

Specified by:

discardUpTo in interface Store

Parameters:

index - the index number to keep -- all previous index numbers will be discarded

Throws:

StoreException - Thrown if the Store is unable to discard the messages.

getLastPersisted

public long getLastPersisted()
                      throws StoreException

Gets the last persisted sequence number.

Specified by:

getLastPersisted in interface Store

Returns:

The last persisted sequence number.

Throws:

StoreException - If an error occurs while retrieving the last persisted sequence number.

getLowestUnpersisted

public long getLowestUnpersisted()

Gets the lowest unpersisted sequence number.

Specified by:

getLowestUnpersisted in interface Store

Returns:

The lowest unpersisted sequence number or -1 if no sequence numbers are unpersisted.

getHighestUnpersisted

public long getHighestUnpersisted()

Gets the highest unpersisted sequence number.

Returns:

The highest unpersisted sequence number or -1 if no sequence numbers are unpersisted.

setMessage

public void setMessage(Message m)

Sets the message to be stored.

Specified by:

setMessage in interface Store

Parameters:

m - The message to be stored.

getErrorOnPublishGap

public boolean getErrorOnPublishGap()

Get whether the Store will throw a PublishGapException from discardUpTo if the sequence number being discarded is less then the current last persisted.

Specified by:

getErrorOnPublishGap in interface Store

Returns:

If true, an exception will be thrown during logon if a gap could be created. If false, logon is allowed to proceed.

setErrorOnPublishGap

public void setErrorOnPublishGap(boolean errorOnGap)

Set whether the Store should throw a PublishGapException from discardUpTo if the sequence number being discarded is less then the current last persisted. This can occur if the client fails over to a server that has not been synchronously replicated to by its previous server, which lead to the new server having a gap in messages from this client.

Specified by:

setErrorOnPublishGap in interface Store

Parameters:

errorOnGap - If true, an exception will be thrown during logon if a gap could be created. If false, allow the logon to proceed.

replay

public void replay(Store.StoreReplayer replayer)
            throws StoreException,
                   DisconnectedException

Replays stored messages onto a store replayer. It processes each block in the list of used blocks, replaying them onto the provided replayer.

Specified by:

replay in interface Store

Parameters:

replayer - The replayer to play messages on.

Throws:

StoreException - If an exception occurs during replay, the method will throw a StoreException, and all following blocks will be ignored.

DisconnectedException - If a disconnection occurs during replay.

replaySingle

public boolean replaySingle(Store.StoreReplayer replayer,
                            long index)
                     throws StoreException,
                            DisconnectedException

Replays a single message from the store, given a specific sequence index, onto a store replayer. If the specified index is less than or equal to the current sequence number, the method will create a message with the correct sequence number and return true. Otherwise, it searches for the block corresponding to the provided index in the list of used blocks, replays the message, and returns true if successful.

Specified by:

replaySingle in interface Store

Parameters:

replayer - The replayer to play the message on.

index - The sequence index of the message to replay.

Returns:

True if the message was successfully replayed or created; false otherwise.

Throws:

StoreException - If an exception occurs during replay, the method will throw a StoreException.

DisconnectedException - If a disconnection occurs during replay.

unpersistedCount

public long unpersistedCount()

Returns the count of unpersisted messages in the store. This count represents the number of messages that have been received but not yet persisted.

Specified by:

unpersistedCount in interface Store

Returns:

The count of unpersisted messages.

recover

protected void recover()
                throws StoreException

Recovers the store's state during initialization. This method parses the store's buffer, reconstructs the used and free lists of blocks, and updates the metadata block accordingly.

Throws:

StoreException - If an error occurs during store recovery.

growFreeListIfEmpty

protected void growFreeListIfEmpty()
                            throws StoreException

Ensures that the free list is not empty by potentially growing it. This method acquires the lock, checks if the free list is empty, and if so, attempts to grow the free list by adding more blocks to it.

Throws:

StoreException - If an error occurs during the process of growing the free list.

flush

public void flush()
           throws TimedOutException

Flushes the publish store. This method blocks until all messages have been successfully flushed or until a timeout occurs.

Specified by:

flush in interface Store

Throws:

TimedOutException - If the flush operation times out before all messages are flushed.

flush

public void flush(long timeout)
           throws TimedOutException

Flushes the publish store, waiting until all messages in the store are flushed or until a timeout occurs. This method allows specifying a timeout for the flush operation.

Specified by:

flush in interface Store

Parameters:

timeout - The maximum time to wait for the flush operation, in milliseconds.

Throws:

TimedOutException - If the flush operation times out before all messages are flushed.

setResizeHandler

public void setResizeHandler(PublishStoreResizeHandler handler)

Sets a resize handler for the publish store. The resize handler is called when the store needs to be resized.

Specified by:

setResizeHandler in interface Store

Parameters:

handler - The resize handler to set.