one.microstream.storage.types

Class StorageDataFileItemIterator.BufferProvider.ConstantSizedBufferProvider

java.lang.Object

one.microstream.storage.types.StorageDataFileItemIterator.BufferProvider.ConstantSizedBufferProvider

All Implemented Interfaces:

StorageDataFileItemIterator.BufferProvider

Enclosing interface:

StorageDataFileItemIterator.BufferProvider

public static final class StorageDataFileItemIterator.BufferProvider.ConstantSizedBufferProvider
extends Object
implements StorageDataFileItemIterator.BufferProvider

Simple implementation that provides always the same ByteBuffer instance with a fixed size. This is sufficient for reading all entity headers and having the data available for caching of "small" entities. Normally, the buffer size is downwards capped at the system's page size which also proved to be the optimal buffer size (anything large gives no significant advantage, anything lower dramatically reduces performance. Both not surprising, given the fundamental meaning of a page size).

Nested Class Summary

Nested classes/interfaces inherited from interface one.microstream.storage.types.StorageDataFileItemIterator.BufferProvider

StorageDataFileItemIterator.BufferProvider.ConstantSizedBufferProvider

Method Summary

Modifier and Type	Method and Description
ByteBuffer	provideBuffer(ByteBuffer byteBuffer, long nextEntityLength) The passed and returned byte buffer instances are guaranteed to be direct bytebuffer.
ByteBuffer	provideInitialBuffer()

Methods inherited from class java.lang.Object

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

Methods inherited from interface one.microstream.storage.types.StorageDataFileItemIterator.BufferProvider

cleanUp, New, NewConstantSized

Method Detail

provideInitialBuffer

public final ByteBuffer provideInitialBuffer()

Specified by:

provideInitialBuffer in interface StorageDataFileItemIterator.BufferProvider

provideBuffer

public final ByteBuffer provideBuffer(ByteBuffer byteBuffer,
                                      long nextEntityLength)

Description copied from interface: StorageDataFileItemIterator.BufferProvider

The passed and returned byte buffer instances are guaranteed to be direct bytebuffer. This has to be ensured via contract instead of proper typing because of the lack of competent typing in the JDK. All byte buffer instances passed to this method are guaranteed to have been created by it. See StorageDataFileItemIterator.BufferProvider.provideInitialBuffer().

Specified by:

provideBuffer in interface StorageDataFileItemIterator.BufferProvider

Parameters:

byteBuffer - the direct byte buffer used so far.

nextEntityLength - the length of the next entity to be read to the buffer.

Returns:

a byte buffer of apriorate size to hold the next entity's data to be processed sufficiently.