com.crankuptheamps.client

Class MemoryPublishStore

java.lang.Object

com.crankuptheamps.client.BlockPublishStore

com.crankuptheamps.client.MemoryPublishStore

All Implemented Interfaces:

Store, java.lang.AutoCloseable

public class MemoryPublishStore
extends BlockPublishStore

An in-memory publish store, used to provide republish capability when a server fails over.

Publish stores hold messages until the AMPS server has acknowledged that they are persisted. When the client detects disconnection and reconnects, the client can republish any messages which have not been acknowledged by AMPS.

Use this PublishStore when you are only concerned about server failover: MemoryPublishStore does not protect you in case of subscriber failure, because it has no persisted backing store.

Nested Class Summary

Nested classes/interfaces inherited from class com.crankuptheamps.client.BlockPublishStore

BlockPublishStore.Buffer, BlockPublishStore.ByteSequence

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

Store.StoreReplayer

Field Summary

Fields

Modifier and Type	Field and Description
static int	BLOCK_SIZE The size of each block the store allocates.

Fields inherited from class com.crankuptheamps.client.BlockPublishStore

_buffer, _errorOnPublishGap, _resizeHandler, AMPS_MIN_PUB_STORE_DISCARDED_VERSION, METADATA_LAST_DISCARDED_LOCATION, METADATA_VERSION_LOCATION

Fields inherited from interface com.crankuptheamps.client.Store

SOWDeleteByBookmark, SOWDeleteByBookmarkCancel, SOWDeleteByData, SOWDeleteByFilter, SOWDeleteByKeys

Constructor Summary

Constructors

Constructor and Description
MemoryPublishStore(int initialCapacity) Construct an in-memory public store with the specified number of blocks as the initial capacity.

Method Summary

Modifier and Type	Method and Description
void	discardUpTo(long index) This method is responsible for managing the discarding of blocks in a store based on the specified index.
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.

Methods inherited from class com.crankuptheamps.client.BlockPublishStore

close, flush, flush, getHighestUnpersisted, getLastPersisted, getLowestUnpersisted, growFreeListIfEmpty, recover, replay, replaySingle, setErrorOnPublishGap, setMessage, setResizeHandler, store, store, unpersistedCount

Methods inherited from class java.lang.Object

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

Field Detail

BLOCK_SIZE

public static final int BLOCK_SIZE

The size of each block the store allocates.

See Also:

Constant Field Values

Constructor Detail

MemoryPublishStore

public MemoryPublishStore(int initialCapacity)
                   throws StoreException

Construct an in-memory public store with the specified number of blocks as the initial capacity. The initial memory footprint will be initialCapacity * BLOCK_SIZE bytes.

Parameters:

initialCapacity - The number of blocks to allocate on construction

Throws:

StoreException - Thrown when an operation fails with details of the failure.

Method Detail

discardUpTo

public void discardUpTo(long index)
                 throws StoreException

Description copied from class: BlockPublishStore

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

Overrides:

discardUpTo in class BlockPublishStore

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.

getErrorOnPublishGap

public boolean getErrorOnPublishGap()

Description copied from class: BlockPublishStore

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

Overrides:

getErrorOnPublishGap in class BlockPublishStore

Returns:

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