org.apache.hadoop.hbase.io.hfile

接口 Cacheable

所有超级接口:

HeapSize

所有已知实现类:

HFileBlock

@InterfaceAudience.Private
public interface Cacheable
extends HeapSize

Cacheable is an interface that allows for an object to be cached. If using an on heap cache, just use heapsize. If using an off heap cache, Cacheable provides methods for serialization of the object. Some objects cannot be moved off heap, those objects will return a getSerializedLength() of 0.

嵌套类概要

嵌套类

限定符和类型	接口和说明
static class	Cacheable.MemoryType SHARED means when this Cacheable is read back from cache it refers to the same memory area as used by the cache for caching it.

方法概要

限定符和类型	方法和说明
BlockType	getBlockType()
CacheableDeserializer<Cacheable>	getDeserializer() Returns CacheableDeserializer instance which reconstructs original object from ByteBuffer.
Cacheable.MemoryType	getMemoryType()
int	getSerializedLength() Returns the length of the ByteBuffer required to serialized the object.
void	serialize(ByteBuffer destination, boolean includeNextBlockMetadata) Serializes its data into destination.

从接口继承的方法 org.apache.hadoop.hbase.io.HeapSize

heapSize

方法详细资料

getSerializedLength

int getSerializedLength()

Returns the length of the ByteBuffer required to serialized the object. If the object cannot be serialized, it should return 0.

返回:

int length in bytes of the serialized form or 0 if the object cannot be cached.

serialize

void serialize(ByteBuffer destination,
               boolean includeNextBlockMetadata)

Serializes its data into destination.

参数:

destination - Where to serialize to

includeNextBlockMetadata - Whether to include nextBlockMetadata in the Cache block.

getDeserializer

CacheableDeserializer<Cacheable> getDeserializer()

Returns CacheableDeserializer instance which reconstructs original object from ByteBuffer.

返回:

CacheableDeserialzer instance.

getBlockType

BlockType getBlockType()

返回:

the block type of this cached HFile block

getMemoryType

Cacheable.MemoryType getMemoryType()

返回:

the MemoryType of this Cacheable