BoundedByteBufferPool (Apache HBase 1.2.12 API)

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java.lang.Object
- org.apache.hadoop.hbase.io.BoundedByteBufferPool

```
@InterfaceAudience.Private
public class BoundedByteBufferPool
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 on the maximum size of ByteBuffer that it will retain (Hence the pool is 'bounded' as opposed to, say, Hadoop's ElasticByteBuffferPool). If a ByteBuffer is bigger than the configured threshold, we will just let the ByteBuffer go rather than add it to the pool. If more ByteBuffers than the configured maximum instances, we will not add the passed ByteBuffer to the pool; we will just drop it (we will log a WARN in this case that we are at capacity).
The intended use case is a reservoir of bytebuffers that an RPC can reuse; buffers tend to achieve a particular 'run' size over time give or take a few extremes. Set TRACE level on this class for a couple of seconds to get reporting on how it is running when deployed.
This class is thread safe.

Field Summary

Fields
Modifier and Type	Field and Description
`private AtomicLong`	`allocations`
`(package private) Queue<ByteBuffer>`	`buffers`
`private ReentrantLock`	`lock`
`private static org.apache.commons.logging.Log`	`LOG`
`private int`	`maxByteBufferSizeToCache`
`(package private) int`	`runningAverage`
`private int`	`totalReservoirCapacity`

Constructor Summary

Constructors
Constructor and Description

BoundedByteBufferPool(int maxByteBufferSizeToCache, int initialByteBufferSize, int maxToCache)

Method Summary

Methods
Modifier and Type Method and Description

ByteBuffer getBuffer()

void putBuffer(ByteBuffer bb)
- Methods inherited from class java.lang.Object
  clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LOG

private static final org.apache.commons.logging.Log LOG

buffers
```
final Queue<ByteBuffer> buffers
```

maxByteBufferSizeToCache

private final int maxByteBufferSizeToCache

runningAverage
```
volatile int runningAverage
```

totalReservoirCapacity

private volatile int totalReservoirCapacity

allocations
```
private AtomicLong allocations
```

lock
```
private ReentrantLock lock
```

Constructor Detail

BoundedByteBufferPool

public BoundedByteBufferPool(int maxByteBufferSizeToCache,
                     int initialByteBufferSize,
                     int maxToCache)

Parameters:: maxByteBufferSizeToCache -; initialByteBufferSize -; maxToCache -

Method Detail

getBuffer
```
public ByteBuffer getBuffer()
```

putBuffer
```
public void putBuffer(ByteBuffer bb)
```

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