com.atlassian.jira.cluster.distribution.localq.tape

Class TapeLocalQCacheOpQueue

java.lang.Object

com.atlassian.jira.cluster.distribution.localq.tape.TapeLocalQCacheOpQueue

All Implemented Interfaces:

LocalQCacheOpQueue

public class TapeLocalQCacheOpQueue
extends Object
implements LocalQCacheOpQueue

Implementation of LocalQCacheOpQueue using tape for storing LocalQCacheOp in local file

Nested Class Summary

Nested classes/interfaces inherited from interface com.atlassian.jira.cluster.distribution.localq.LocalQCacheOpQueue

LocalQCacheOpQueue.QueueId

Method Summary

Modifier and Type	Method and Description
boolean	add(LocalQCacheOp localQCacheOp) transactional add of LocalQCacheOp to the queue; when operation finished we "guarantee" that the LocalQCacheOp is persisted
void	backupQueue(String prefix) Note: use with caution This method is mainly designed to handle critical state of the queue storage by backing up the current queue persistent store and recreating a new one.
void	close() closes the queue and all resources connected with this queue (like processing thread(s), files); closing a queue is definitive - it will never be open (i.e.
static TapeLocalQCacheOpQueue	create(File localDirectoryForQueues, Node node, int nodeQueueNumber, boolean replicatePutsViaCopy)
boolean	equals(Object o)
int	hashCode()
boolean	hasPermission()
LocalQCacheOpQueue.QueueId	id()
boolean	isClosed() Some operations (LocalQCacheOpQueue.add(LocalQCacheOp), LocalQCacheOpQueue.remove(), LocalQCacheOpQueue.peek(), LocalQCacheOpQueue.peekOrBlock()) on a closed queue will throw a IllegalStateException.
String	name()
LocalQCacheOp	peek() Allows to see whats on the head of the queue without removing it
LocalQCacheOp	peekOrBlock() see LocalQCacheOpQueue.peek() but will block when the queue is empty;
void	remove() remove LocalQCacheOp from head of the queue
int	size()
Long	usableSpaceInBytes()

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.atlassian.jira.cluster.distribution.localq.LocalQCacheOpQueue

nodeQueueNumber, nodeQueueNumberForCurrentThread

Method Detail

create

public static TapeLocalQCacheOpQueue create(File localDirectoryForQueues,
                                            Node node,
                                            int nodeQueueNumber,
                                            boolean replicatePutsViaCopy)
                                     throws IOException

Throws:

IOException

close

public void close()

Description copied from interface: LocalQCacheOpQueue

closes the queue and all resources connected with this queue (like processing thread(s), files); closing a queue is definitive - it will never be open (i.e. not-closed) again;

Specified by:

close in interface LocalQCacheOpQueue

isClosed

public boolean isClosed()

Description copied from interface: LocalQCacheOpQueue

Some operations (LocalQCacheOpQueue.add(LocalQCacheOp), LocalQCacheOpQueue.remove(), LocalQCacheOpQueue.peek(), LocalQCacheOpQueue.peekOrBlock()) on a closed queue will throw a IllegalStateException. This method allows to check if the queue has not been closed.

Specified by:

isClosed in interface LocalQCacheOpQueue

Returns:

true if queue is closed

name

public String name()

Specified by:

name in interface LocalQCacheOpQueue

Returns:

node name, something meaningful for the user (so it can be identified in the logs)

id

public LocalQCacheOpQueue.QueueId id()

Specified by:

id in interface LocalQCacheOpQueue

Returns:

queue id which uniquely identifies this queue, i.e destination node and nodeQueueNumber, see LocalQCacheOpQueue.QueueId

add

public boolean add(LocalQCacheOp localQCacheOp)
            throws IllegalStateException

Description copied from interface: LocalQCacheOpQueue

transactional add of LocalQCacheOp to the queue; when operation finished we "guarantee" that the LocalQCacheOp is persisted

Specified by:

add in interface LocalQCacheOpQueue

Returns:

true if message was added or false if dropped (like exceeding queue size limit)

Throws:

IllegalStateException - when queue is closed

peek

@Nullable
public LocalQCacheOp peek()

Description copied from interface: LocalQCacheOpQueue

Allows to see whats on the head of the queue without removing it

Specified by:

peek in interface LocalQCacheOpQueue

Returns:

localQCacheOp from queue head or null when queue is empty

peekOrBlock

@Nullable
public LocalQCacheOp peekOrBlock()
                                    throws InterruptedException,
                                           IllegalStateException

Description copied from interface: LocalQCacheOpQueue

see LocalQCacheOpQueue.peek() but will block when the queue is empty;

Specified by:

peekOrBlock in interface LocalQCacheOpQueue

Returns:

localQCacheOp from queue head, blocks when the queue is empty, null when queue is closed when in block

Throws:

InterruptedException

IllegalStateException - when queue is closed (when calling this method queue is already closed)

remove

public void remove()
            throws NoSuchElementException,
                   IllegalStateException

Description copied from interface: LocalQCacheOpQueue

remove LocalQCacheOp from head of the queue

Specified by:

remove in interface LocalQCacheOpQueue

Throws:

NoSuchElementException - when doing a remove on an empty queue

IllegalStateException - when queue is closed

size

public int size()

Specified by:

size in interface LocalQCacheOpQueue

Returns:

number of elements in this queue

backupQueue

public void backupQueue(String prefix)
                 throws IOException

Description copied from interface: LocalQCacheOpQueue

Note: use with caution This method is mainly designed to handle critical state of the queue storage by backing up the current queue persistent store and recreating a new one. Renames current queue file name to [prefix]_[queue_file_name] and re-creates queue file with [queue_file_name]. If file with [prefix]_[queue_file_name] already exists it will be deleted. Note that if LocalQCacheOpQueue.backupQueue(String) is called between LocalQCacheOpQueue.peek() and LocalQCacheOpQueue.remove() this can cause LocalQCacheOpQueue.remove() to delete a different LocalQCacheOp then expected or may throw NoSuchElementException if the new queue after LocalQCacheOpQueue.backupQueue(String) is empty.

Specified by:

backupQueue in interface LocalQCacheOpQueue

Throws:

IOException

usableSpaceInBytes

public Long usableSpaceInBytes()

Specified by:

usableSpaceInBytes in interface LocalQCacheOpQueue

Returns:

number of bytes left on device where this queue is stored or null if unable to get this value

hasPermission

public boolean hasPermission()

Specified by:

hasPermission in interface LocalQCacheOpQueue

Returns:

true if has read/write access to queue storage

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object