LruCachedBlock (Apache HBase 1.2.12 API)

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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

Methods
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()
```

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