Top Description Inners Fields Constructors Methods
org.xerial.snappy.pool

public final Class CachingBufferPool

extends Object
implements BufferPool
Class Inheritance
All Implemented Interfaces
org.xerial.snappy.pool.BufferPool
Imports
java.lang.ref.SoftReference, java.nio.ByteBuffer, java.util.concurrent.ConcurrentHashMap, .ConcurrentLinkedDeque, .ConcurrentMap
A BufferPool implementation which caches values at fixed sizes.

Pooled instances are held as SoftReference to allow GC if necessary.

The current fixed sizes are calculated as follows:

Author
Brett Okken

Nested and Inner Type Summary

Modifier and TypeClass and Description
private static interface
CachingBufferPool.IntFunction<E>

Field Summary

Modifier and TypeField and Description
private static final CachingBufferPool.IntFunction<byte[]>
ARRAY_FUNCTION

private final ConcurrentMap<Integer, ConcurrentLinkedDeque<SoftReference<ByteBuffer>>>
buffers

private final ConcurrentMap<Integer, ConcurrentLinkedDeque<SoftReference<byte[]>>>
bytes

private static final CachingBufferPool.IntFunction<ByteBuffer>
DBB_FUNCTION

private static final CachingBufferPool
INSTANCE

Constructor Summary

AccessConstructor and Description
private
CachingBufferPool()

Method Summary

Modifier and TypeMethod and Description
pack-priv static int
adjustSize(int size)

public byte[]
allocateArray(int
The minimum size array required. Must be >= 0.
size)

Implements org.xerial.snappy.pool.BufferPool.allocateArray.

Returns a byte[] of size or greater length.

public ByteBuffer
allocateDirect(int
The minimum size buffer required. Must be >= 0.
size)

Implements org.xerial.snappy.pool.BufferPool.allocateDirect.

Returns a direct ByteBuffer of size or greater capacity.

public static BufferPool

Returns:

instance of CachingBufferPool for using cached buffers.
getInstance()

Returns instance of CachingBufferPool for using cached buffers.

private static <E> E
getOrCreate(final int size, final ConcurrentMap<Integer, ConcurrentLinkedDeque<SoftReference<E>>> map, final CachingBufferPool.IntFunction<E> creator)

private static <E> ConcurrentLinkedDeque<SoftReference<E>>
optimisticGetEntry(Integer key, ConcurrentMap<Integer, ConcurrentLinkedDeque<SoftReference<E>>> map)

public void
releaseArray(byte[]
Instance to return to pool. Must not be null. Must not be returned more than 1 time. Must not be used by caller after return.
buffer)

Implements org.xerial.snappy.pool.BufferPool.releaseArray.

Returns instance to pool for potential future reuse.

public void
releaseDirect(ByteBuffer
Instance to return to pool. Must not be null. Must not be returned more than 1 time. Must not be used by caller after return.
buffer)

Implements org.xerial.snappy.pool.BufferPool.releaseDirect.

Returns instance to pool for potential future reuse.

private static <E> void
returnValue(E value, Integer size, ConcurrentMap<Integer, ConcurrentLinkedDeque<SoftReference<E>>> map)

private static int
roundToPowers(int number, int bits)

public String
toString()

Overrides java.lang.Object.toString.

Returns a string representation of the object.

Inherited from java.lang.Object:
cloneequalsfinalizegetClasshashCodenotifynotifyAllwaitwaitwait

Field Detail

ARRAY_FUNCTIONback to summary
private static final CachingBufferPool.IntFunction<byte[]> ARRAY_FUNCTION
buffersback to summary
private final ConcurrentMap<Integer, ConcurrentLinkedDeque<SoftReference<ByteBuffer>>> buffers
bytesback to summary
private final ConcurrentMap<Integer, ConcurrentLinkedDeque<SoftReference<byte[]>>> bytes
DBB_FUNCTIONback to summary
private static final CachingBufferPool.IntFunction<ByteBuffer> DBB_FUNCTION
INSTANCEback to summary
private static final CachingBufferPool INSTANCE

Constructor Detail

CachingBufferPoolback to summary
private CachingBufferPool()

Method Detail

adjustSizeback to summary
pack-priv static int adjustSize(int size)
allocateArrayback to summary
public byte[] allocateArray(int size)

Implements org.xerial.snappy.pool.BufferPool.allocateArray.

Doc from org.xerial.snappy.pool.BufferPool.allocateArray.

Returns a byte[] of size or greater length.

Parameters
size:int

The minimum size array required. Must be >= 0.

Returns:byte[]

A byte[] with length of at least size.

Annotations
@Override
allocateDirectback to summary
public ByteBuffer allocateDirect(int size)

Implements org.xerial.snappy.pool.BufferPool.allocateDirect.

Doc from org.xerial.snappy.pool.BufferPool.allocateDirect.

Returns a direct ByteBuffer of size or greater capacity.

Parameters
size:int

The minimum size buffer required. Must be >= 0.

Returns:ByteBuffer

A ByteBuffer of size or greater capacity.

Annotations
@Override
getInstanceback to summary
public static BufferPool getInstance()

Returns instance of CachingBufferPool for using cached buffers.

Returns:BufferPool

instance of CachingBufferPool for using cached buffers.

getOrCreateback to summary
private static <E> E getOrCreate(final int size, final ConcurrentMap<Integer, ConcurrentLinkedDeque<SoftReference<E>>> map, final CachingBufferPool.IntFunction<E> creator)
optimisticGetEntryback to summary
private static <E> ConcurrentLinkedDeque<SoftReference<E>> optimisticGetEntry(Integer key, ConcurrentMap<Integer, ConcurrentLinkedDeque<SoftReference<E>>> map)
releaseArrayback to summary
public void releaseArray(byte[] buffer)

Implements org.xerial.snappy.pool.BufferPool.releaseArray.

Doc from org.xerial.snappy.pool.BufferPool.releaseArray.

Returns instance to pool for potential future reuse.

Must not be returned more than 1 time. Must not be used by caller after return.

Parameters
buffer:byte[]

Instance to return to pool. Must not be null. Must not be returned more than 1 time. Must not be used by caller after return.

Annotations
@Override
releaseDirectback to summary
public void releaseDirect(ByteBuffer buffer)

Implements org.xerial.snappy.pool.BufferPool.releaseDirect.

Doc from org.xerial.snappy.pool.BufferPool.releaseDirect.

Returns instance to pool for potential future reuse.

Must not be returned more than 1 time. Must not be used by caller after return.

Parameters
buffer:ByteBuffer

Instance to return to pool. Must not be null. Must not be returned more than 1 time. Must not be used by caller after return.

Annotations
@Override
returnValueback to summary
private static <E> void returnValue(E value, Integer size, ConcurrentMap<Integer, ConcurrentLinkedDeque<SoftReference<E>>> map)
roundToPowersback to summary
private static int roundToPowers(int number, int bits)
toStringback to summary
public String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object. Satisfying this method's contract implies a non-null result must be returned.

Returns:String

a string representation of the object

Annotations
@Override
org.xerial.snappy.pool back to summary

private Interface CachingBufferPool.IntFunction<E>

Method Summary

Modifier and TypeMethod and Description
public E
create(int size)

Method Detail

createback to summary
public E create(int size)