All Known Implementing Classes:

TapePerNodeLocalQueue, TapePerNodeLocalQueueWithStats
```
public interface PerNodeLocalQueue
```
Abstracts persistent queue implementation A queue represents a FIFO queue of CrossNodesEvent for a specific node BambooNodeInfo. Each node may have from 1 to n queues. Each queue has a single processing (reading) process so BambooClusterSettings.NUMBER_OF_PHYSICAL_QUEUES_UNDER_PER_NODE_QUEUE i.e. the number of processes for each node. BambooClusterSettings.NUMBER_OF_PHYSICAL_QUEUES_UNDER_PER_NODE_QUEUE is the concurrency factor for communicating with a single remote node. Example: if we have a cluster with 3 nodes (node1, node2, node3) on each node there will be BambooClusterSettings.NUMBER_OF_PHYSICAL_QUEUES_UNDER_PER_NODE_QUEUE queues for each of the "other" 2 remote nodes.

Since:

9.5

Nested Class Summary

Nested Classes
Modifier and Type Interface Description

static class PerNodeLocalQueue.QueueId
Uniquely identifies a queue

Field Summary

Fields
Modifier and Type Field Description

static int NUMBER_OF_PHYSICAL_QUEUES_PER_NODE

Method Summary

All Methods Static Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`boolean`	`add(CrossNodesEvent data)`	transactional add of `CrossNodesEvent` to the queue; when operation finished we "guarantee" that the `CrossNodesEvent` 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. not-closed) again;
`@NotNull Optional<Path>`	`getQueueFilePath()`
`boolean`	`hasPermission()`
`@NotNull PerNodeLocalQueue.QueueId`	`id()`
`boolean`	`isClosed()`	Some operations (like `add(CrossNodesEvent)`) on a closed queue will throw a `IllegalStateException`.
`@NotNull String`	`name()`
`static int`	`nodeQueueNumber(long threadId)`	Utility method to get the nodeQueueNumber for given thread id.
`static int`	`nodeQueueNumberForCurrentThread()`	Utility method to get the nodeQueueNumber for current thread.
`@Nullable CrossNodesEvent`	`peek()`	Allows to see what's on the head of the queue without removing it.
`void`	`remove()`	Remove `CrossNodesEvent` from head of the queue.
`int`	`size()`
`@Nullable Long`	`usableSpaceInBytes()`

- Field Detail
  - NUMBER_OF_PHYSICAL_QUEUES_PER_NODE
```
static final int NUMBER_OF_PHYSICAL_QUEUES_PER_NODE
```
- Method Detail
  - close
```
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. not-closed) again;
  - isClosed
```
boolean isClosed()
```
    Some operations (like add(CrossNodesEvent)) on a closed queue will throw a IllegalStateException. This method allows to check if the queue has not been closed.
    
    Returns:
    
    true if queue is closed
  - name
```
@NotNull
@NotNull String name()
```
    Returns:
    
    name of the queue could be useful for the user, like identifying the queue file path from logs
  - id
```
@NotNull
@NotNull PerNodeLocalQueue.QueueId id()
```
    Returns:
    
    queue id which uniquely identifies this queue, i.e destination node and nodeQueueNumber, see PerNodeLocalQueue.QueueId
  - add
```
boolean add(CrossNodesEvent data)
     throws IllegalStateException
```
    transactional add of CrossNodesEvent to the queue; when operation finished we "guarantee" that the CrossNodesEvent is persisted
    
    Parameters:
    
    data -
    
    Returns:
    
    true if message was added or false if dropped (like exceeding queue size limit)
    
    Throws:
    
    IllegalStateException - when queue is closed
  - peek
```
@Nullable
@Nullable CrossNodesEvent peek()
                        throws IllegalStateException
```
    Allows to see what's on the head of the queue without removing it.
    
    Returns:
    
    crossNodesEvent from queue head or null when queue is empty.
    
    Throws:
    
    IllegalStateException - when queue is closed
  - remove
```
void remove()
     throws NoSuchElementException,
            IllegalStateException
```
    Remove CrossNodesEvent from head of the queue.
    
    Throws:
    
    NoSuchElementException - when doing a remove on an empty queue
    
    IllegalStateException - when queue is closed
  - getQueueFilePath
```
@NotNull
@NotNull Optional<Path> getQueueFilePath()
```
    Returns:
    
    the queue file path if exists, empty otherwise
  - hasPermission
```
boolean hasPermission()
```
    Returns:
    
    true if it has read/write access to queue storage
  - usableSpaceInBytes
```
@Nullable
@Nullable Long usableSpaceInBytes()
```
    Returns:
    
    number of bytes left on device where this queue is stored or null if unable to get this value
  - size
```
int size()
```
    Returns:
    
    number of elements in this queue
  - backupQueue
```
void backupQueue(String prefix)
          throws IOException
```
    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 backupQueue(String) is called between peek() and remove() this can cause remove() to delete a different CrossNodesEvent then expected or may throw NoSuchElementException if the new queue after backupQueue(String) is empty.
    
    Throws:
    
    IOException
  - nodeQueueNumberForCurrentThread
```
static int nodeQueueNumberForCurrentThread()
```
    Utility method to get the nodeQueueNumber for current thread.
    
    Returns:
    
    nodeQueueNumber for current thread
  - nodeQueueNumber
```
static int nodeQueueNumber(long threadId)
```
    Utility method to get the nodeQueueNumber for given thread id.
    
    Returns:
    
    nodeQueueNumber for given thread id

Interface PerNodeLocalQueue

Nested Class Summary

Field Summary

Method Summary

Field Detail

NUMBER_OF_PHYSICAL_QUEUES_PER_NODE

Method Detail

close

isClosed

name

id

add

peek

remove

getQueueFilePath

hasPermission

usableSpaceInBytes

size

backupQueue

nodeQueueNumberForCurrentThread

nodeQueueNumber