org.apache.hadoop.hbase.io

Class ByteBufferPool

java.lang.Object

org.apache.hadoop.hbase.io.ByteBufferPool

@InterfaceAudience.Private
public class ByteBufferPool
extends Object

Like Hadoops' ByteBufferPool only you do not specify desired size when getting a ByteBuffer. This pool keeps an upper bound on the count of ByteBuffers in the pool and a fixed size of ByteBuffer that it will create. When requested, if a free ByteBuffer is already present, it will return that. And when no free ByteBuffer available and we are below the max count, it will create a new one and return that.

Note: This pool returns off heap ByteBuffers by default. If on heap ByteBuffers to be pooled, pass 'directByteBuffer' as false while construction of the pool.

This class is thread safe.

See Also:

ByteBufferListOutputStream

Field Summary

Fields

Modifier and Type	Field and Description
static String	BUFFER_SIZE_KEY
static int	DEFAULT_BUFFER_SIZE
static String	MAX_POOL_SIZE_KEY

Constructor Summary

Constructors

Constructor and Description
ByteBufferPool(int bufferSize, int maxPoolSize)
ByteBufferPool(int bufferSize, int maxPoolSize, boolean directByteBuffer)

Method Summary

Modifier and Type	Method and Description
ByteBuffer	getBuffer()
int	getBufferSize()
int	getQueueSize()
void	putbackBuffer(ByteBuffer buf) Return back a ByteBuffer after its use.

Methods inherited from class java.lang.Object

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

Field Detail

MAX_POOL_SIZE_KEY

public static final String MAX_POOL_SIZE_KEY

See Also:

Constant Field Values

BUFFER_SIZE_KEY

public static final String BUFFER_SIZE_KEY

See Also:

Constant Field Values

DEFAULT_BUFFER_SIZE

public static final int DEFAULT_BUFFER_SIZE

See Also:

Constant Field Values

Constructor Detail

ByteBufferPool

public ByteBufferPool(int bufferSize,
                      int maxPoolSize)

Parameters:

bufferSize - Size of each buffer created by this pool.

maxPoolSize - Max number of buffers to keep in this pool.

ByteBufferPool

public ByteBufferPool(int bufferSize,
                      int maxPoolSize,
                      boolean directByteBuffer)

Parameters:

bufferSize - Size of each buffer created by this pool.

maxPoolSize - Max number of buffers to keep in this pool.

directByteBuffer - Whether to create direct ByteBuffer or on heap ByteBuffer.

Method Detail

getBuffer

public ByteBuffer getBuffer()

Returns:

One free ByteBuffer from the pool. If no free ByteBuffer and we have not reached the maximum pool size, it will create a new one and return. In case of max pool size also reached, will return null. When pool returned a ByteBuffer, make sure to return it back to pool after use.

See Also:

putbackBuffer(ByteBuffer)

putbackBuffer

public void putbackBuffer(ByteBuffer buf)

Return back a ByteBuffer after its use. Do not try to return put back a ByteBuffer, not obtained from this pool.

Parameters:

buf - ByteBuffer to return.

getBufferSize

public int getBufferSize()

getQueueSize

public int getQueueSize()

Returns:

Number of free buffers