org.apache.hadoop.hbase.io.hfile

Class LruCachedBlock

java.lang.Object

org.apache.hadoop.hbase.io.hfile.LruCachedBlock

All Implemented Interfaces:

Comparable<LruCachedBlock>, HeapSize

@InterfaceAudience.Private
public class LruCachedBlock
extends Object
implements HeapSize, Comparable<LruCachedBlock>

Represents an entry in the LruBlockCache.

Makes the block memory-aware with HeapSize and Comparable to sort by access time for the LRU. It also takes care of priority by either instantiating as in-memory or handling the transition from single to multiple access.

Field Summary

Fields

Modifier and Type	Field and Description
private long	accessTime
private Cacheable	buf
private long	cachedTime Time this block was cached.
private BlockCacheKey	cacheKey
static long	PER_BLOCK_OVERHEAD
private BlockPriority	priority
private long	size

Constructor Summary

Constructors

Constructor and Description
LruCachedBlock(BlockCacheKey cacheKey, Cacheable buf, long accessTime)
LruCachedBlock(BlockCacheKey cacheKey, Cacheable buf, long accessTime, boolean inMemory)

Method Summary

Modifier and Type	Method and Description
void	access(long accessTime) Block has been accessed.
int	compareTo(LruCachedBlock that)
boolean	equals(Object obj)
Cacheable	getBuffer()
long	getCachedTime()
BlockCacheKey	getCacheKey()
BlockPriority	getPriority()
int	hashCode()
long	heapSize()

Methods inherited from class java.lang.Object

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

Field Detail

PER_BLOCK_OVERHEAD

public static final long PER_BLOCK_OVERHEAD

cacheKey

private final BlockCacheKey cacheKey

buf

private final Cacheable buf

accessTime

private volatile long accessTime

size

private long size

priority

private BlockPriority priority

cachedTime

private final long cachedTime

Time this block was cached. Presumes we are created just before we are added to the cache.

Constructor Detail

LruCachedBlock

public LruCachedBlock(BlockCacheKey cacheKey,
                      Cacheable buf,
                      long accessTime)

LruCachedBlock

public LruCachedBlock(BlockCacheKey cacheKey,
                      Cacheable buf,
                      long accessTime,
                      boolean inMemory)

Method Detail

access

public void access(long accessTime)

Block has been accessed.

Parameters:

accessTime - Last access; this is actually a incremented sequence number rather than an actual time.

getCachedTime

public long getCachedTime()

Returns:

Time we were cached at in nano seconds.

heapSize

public long heapSize()

Specified by:

heapSize in interface HeapSize

Returns:

Approximate 'exclusive deep size' of implementing object. Includes count of payload and hosting object sizings.

compareTo

public int compareTo(LruCachedBlock that)

Specified by:

compareTo in interface Comparable<LruCachedBlock>

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

getBuffer

public Cacheable getBuffer()

getCacheKey

public BlockCacheKey getCacheKey()

getPriority

public BlockPriority getPriority()