BlockCache (Apache HBase 2.5.0 API)

All Superinterfaces:

Iterable<CachedBlock>

All Known Subinterfaces:

FirstLevelBlockCache, ResizableBlockCache

All Known Implementing Classes:

BucketCache, CombinedBlockCache, InclusiveCombinedBlockCache, IndexOnlyLruBlockCache, LruAdaptiveBlockCache, LruBlockCache, MemcachedBlockCache, TinyLfuBlockCache
```
@InterfaceAudience.Private
public interface BlockCache
extends Iterable<CachedBlock>
```
Block cache interface. Anything that implements the Cacheable interface can be put in the cache.

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method and Description
`void`	`cacheBlock(BlockCacheKey cacheKey, Cacheable buf)` Add block to cache (defaults to not in-memory).
`void`	`cacheBlock(BlockCacheKey cacheKey, Cacheable buf, boolean inMemory)` Add block to cache.
`boolean`	`evictBlock(BlockCacheKey cacheKey)` Evict block from cache.
`int`	`evictBlocksByHfileName(String hfileName)` Evicts all blocks for the given HFile.
`Cacheable`	`getBlock(BlockCacheKey cacheKey, boolean caching, boolean repeat, boolean updateCacheMetrics)` Fetch block from cache.
`BlockCache[]`	`getBlockCaches()` Returns The list of sub blockcaches that make up this one; returns null if no sub caches.
`long`	`getBlockCount()` Returns the number of blocks currently cached in the block cache.
`long`	`getCurrentDataSize()` Returns the occupied size of data blocks, in bytes.
`long`	`getCurrentSize()` Returns the occupied size of the block cache, in bytes.
`long`	`getDataBlockCount()` Returns the number of data blocks currently cached in the block cache.
`long`	`getFreeSize()` Returns the free size of the block cache, in bytes.
`long`	`getMaxSize()` Returns the Max size of the block cache, in bytes.
`CacheStats`	`getStats()` Get the statistics for this block cache.
`default boolean`	`isMetaBlock(BlockType blockType)` Check if block type is meta or index block
`Iterator<CachedBlock>`	`iterator()` Returns Iterator over the blocks in the cache.
`void`	`shutdown()` Shutdown the cache.
`long`	`size()` Returns the total size of the block cache, in bytes.

Methods inherited from interface java.lang.Iterable
forEach, spliterator

- Method Detail
  - cacheBlock
```
void cacheBlock(BlockCacheKey cacheKey,
                Cacheable buf,
                boolean inMemory)
```
    Add block to cache.
    
    Parameters:
    
    cacheKey - The block's cache key.
    
    buf - The block contents wrapped in a ByteBuffer.
    
    inMemory - Whether block should be treated as in-memory
  - cacheBlock
```
void cacheBlock(BlockCacheKey cacheKey,
                Cacheable buf)
```
    Add block to cache (defaults to not in-memory).
    
    Parameters:
    
    cacheKey - The block's cache key.
    
    buf - The object to cache.
  - getBlock
```
Cacheable getBlock(BlockCacheKey cacheKey,
                   boolean caching,
                   boolean repeat,
                   boolean updateCacheMetrics)
```
    Fetch block from cache.
    
    Parameters:
    
    cacheKey - Block to fetch.
    
    caching - Whether this request has caching enabled (used for stats)
    
    repeat - Whether this is a repeat lookup for the same block (used to avoid double counting cache misses when doing double-check locking)
    
    updateCacheMetrics - Whether to update cache metrics or not
    
    Returns:
    
    Block or null if block is not in 2 cache.
  - evictBlock
```
boolean evictBlock(BlockCacheKey cacheKey)
```
    Evict block from cache.
    
    Parameters:
    
    cacheKey - Block to evict
    
    Returns:
    
    true if block existed and was evicted, false if not
  - evictBlocksByHfileName
```
int evictBlocksByHfileName(String hfileName)
```
    Evicts all blocks for the given HFile.
    
    Returns:
    
    the number of blocks evicted
  - getStats
```
CacheStats getStats()
```
    Get the statistics for this block cache. n
  - shutdown
```
void shutdown()
```
    Shutdown the cache.
  - size
```
long size()
```
    Returns the total size of the block cache, in bytes.
    
    Returns:
    
    size of cache, in bytes
  - getMaxSize
```
long getMaxSize()
```
    Returns the Max size of the block cache, in bytes.
    
    Returns:
    
    size of cache, in bytes
  - getFreeSize
```
long getFreeSize()
```
    Returns the free size of the block cache, in bytes.
    
    Returns:
    
    free space in cache, in bytes
  - getCurrentSize
```
long getCurrentSize()
```
    Returns the occupied size of the block cache, in bytes.
    
    Returns:
    
    occupied space in cache, in bytes
  - getCurrentDataSize
```
long getCurrentDataSize()
```
    Returns the occupied size of data blocks, in bytes.
    
    Returns:
    
    occupied space in cache, in bytes
  - getBlockCount
```
long getBlockCount()
```
    Returns the number of blocks currently cached in the block cache.
    
    Returns:
    
    number of blocks in the cache
  - getDataBlockCount
```
long getDataBlockCount()
```
    Returns the number of data blocks currently cached in the block cache.
    
    Returns:
    
    number of blocks in the cache
  - iterator
```
Iterator<CachedBlock> iterator()
```
    Returns Iterator over the blocks in the cache.
    
    Specified by:
    
    iterator in interface Iterable<CachedBlock>
  - getBlockCaches
```
BlockCache[] getBlockCaches()
```
    Returns The list of sub blockcaches that make up this one; returns null if no sub caches.
  - isMetaBlock
```
default boolean isMetaBlock(BlockType blockType)
```
    Check if block type is meta or index block
    
    Parameters:
    
    blockType - block type of a given HFile block
    
    Returns:
    
    true if block type is non-data block

Interface BlockCache

Method Summary

Methods inherited from interface java.lang.Iterable

Method Detail

cacheBlock

cacheBlock

getBlock

evictBlock

evictBlocksByHfileName

getStats

shutdown

size

getMaxSize

getFreeSize

getCurrentSize

getCurrentDataSize

getBlockCount

getDataBlockCount

iterator

getBlockCaches

isMetaBlock