Package org.apache.hadoop.hbase.io.hfile.bucket

Class CachedEntryQueue

java.lang.Object

org.apache.hadoop.hbase.io.hfile.bucket.CachedEntryQueue

@Private
public class CachedEntryQueue
extends Object

A memory-bound queue that will grow until an element brings total size larger than 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.

Field Summary

Fields

Modifier and Type	Field	Description
private long	cacheSize
private static final Comparator<Map.Entry<BlockCacheKey,BucketEntry>>	COMPARATOR
private long	maxSize
private org.apache.hbase.thirdparty.com.google.common.collect.MinMaxPriorityQueue<Map.Entry<BlockCacheKey,BucketEntry>>	queue

Constructor Summary

Constructors

Constructor	Description
CachedEntryQueue(long maxSize, long blockSize)

Method Summary

Modifier and Type	Method	Description
void	add(Map.Entry<BlockCacheKey,BucketEntry> entry)	Attempt to add the specified entry to this queue.
Map.Entry<BlockCacheKey,BucketEntry>	poll()	Returns The next element in this queue, or null if the queue is empty.
Map.Entry<BlockCacheKey,BucketEntry>	pollLast()	Returns The last element in this queue, or null if the queue is empty.

Methods inherited from class java.lang.Object

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

Field Details

COMPARATOR

private static final Comparator<Map.Entry<BlockCacheKey,BucketEntry>> COMPARATOR

queue

private org.apache.hbase.thirdparty.com.google.common.collect.MinMaxPriorityQueue<Map.Entry<BlockCacheKey,BucketEntry>> queue

cacheSize

private long cacheSize

maxSize

private long maxSize

Constructor Details

CachedEntryQueue

public CachedEntryQueue(long maxSize,
 long blockSize)

Parameters:

maxSize - the target size of elements in the queue

blockSize - expected average size of blocks

Method Details

add

public void add(Map.Entry<BlockCacheKey,BucketEntry> entry)

Attempt to add the specified entry to this queue.

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

Parameters:

entry - a bucket entry with key to try to add to the queue

poll

public Map.Entry<BlockCacheKey,BucketEntry> poll()

Returns The next element in this queue, or null if the queue is empty.

pollLast

public Map.Entry<BlockCacheKey,BucketEntry> pollLast()

Returns The last element in this queue, or null if the queue is empty.