org.apache.accumulo.core.file.blockfile.cache

Class CachedBlockQueue

java.lang.Object

org.apache.accumulo.core.file.blockfile.cache.CachedBlockQueue

All Implemented Interfaces:

HeapSize

public class CachedBlockQueue
extends Object
implements HeapSize

A memory-bound queue that will grow until an element brings total size >= maxSize. From then on, only entries that are sorted larger than the smallest current entry will be inserted/replaced.

Use this when you want to find the largest elements (according to their ordering, not their heap size) that consume as close to the specified maxSize as possible. Default behavior is to grow just above rather than just below specified max.

Object used in this queue must implement HeapSize as well as Comparable.

Constructor Summary

Constructors

Constructor and Description
CachedBlockQueue(long maxSize, long blockSize)

Method Summary

Methods

Modifier and Type	Method and Description
void	add(CachedBlock cb) Attempt to add the specified cached block to this queue.
CachedBlock[]	get() Get a sorted List of all elements in this queue, in descending order.
LinkedList<CachedBlock>	getList() Get a sorted List of all elements in this queue, in descending order.
long	heapSize() Total size of all elements in this queue.

Methods inherited from class java.lang.Object

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

Constructor Detail

CachedBlockQueue

public CachedBlockQueue(long maxSize,
                long blockSize)

Parameters:

maxSize - the target size of elements in the queue

blockSize - expected average size of blocks

Method Detail

add

public void add(CachedBlock cb)

Attempt to add the specified cached block to this queue.

If the queue is smaller than the max size, or if the specified element is ordered before the smallest element in the queue, the element will be added to the queue. Otherwise, there is no side effect of this call.

Parameters:

cb - block to try to add to the queue

get

public CachedBlock[] get()

Get a sorted List of all elements in this queue, in descending order.

Returns:

list of cached elements in descending order

getList

public LinkedList<CachedBlock> getList()

Get a sorted List of all elements in this queue, in descending order.

Returns:

list of cached elements in descending order

heapSize

public long heapSize()

Total size of all elements in this queue.

Specified by:

heapSize in interface HeapSize

Returns:

size of all elements currently in queue, in bytes