Package org.apache.bookkeeper.bookie.storage.ldb

Class WriteCache

java.lang.Object

org.apache.bookkeeper.bookie.storage.ldb.WriteCache

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

public class WriteCache
extends java.lang.Object
implements java.io.Closeable

Write cache implementation.

The write cache will allocate the requested size from direct memory and it will break it down into multiple segments.

The entries are appended in a common buffer and indexed though a hashmap, until the cache is cleared.

There is the possibility to iterate through the stored entries in an ordered way, by (ledgerId, entry).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	WriteCache.EntryConsumer	Consumer that is used to scan the entire write cache.

Constructor Summary

Constructors

Constructor	Description
WriteCache(io.netty.buffer.ByteBufAllocator allocator, long maxCacheSize)
WriteCache(io.netty.buffer.ByteBufAllocator allocator, long maxCacheSize, int maxSegmentSize)

Method Summary

Modifier and Type	Method	Description
(package private) static int	align64(int size)
void	clear()
void	close()
long	count()
void	deleteLedger(long ledgerId)
void	forEach(WriteCache.EntryConsumer consumer)
io.netty.buffer.ByteBuf	get(long ledgerId, long entryId)
io.netty.buffer.ByteBuf	getLastEntry(long ledgerId)
boolean	hasEntry(long ledgerId, long entryId)
boolean	isEmpty()
boolean	put(long ledgerId, long entryId, io.netty.buffer.ByteBuf entry)
long	size()

Methods inherited from class java.lang.Object

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

Constructor Detail

WriteCache

public WriteCache(io.netty.buffer.ByteBufAllocator allocator,
                  long maxCacheSize)

WriteCache

public WriteCache(io.netty.buffer.ByteBufAllocator allocator,
                  long maxCacheSize,
                  int maxSegmentSize)

Method Detail

clear

public void clear()

close

public void close()

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface java.io.Closeable

put

public boolean put(long ledgerId,
                   long entryId,
                   io.netty.buffer.ByteBuf entry)

get

public io.netty.buffer.ByteBuf get(long ledgerId,
                                   long entryId)

hasEntry

public boolean hasEntry(long ledgerId,
                        long entryId)

getLastEntry

public io.netty.buffer.ByteBuf getLastEntry(long ledgerId)

deleteLedger

public void deleteLedger(long ledgerId)

forEach

public void forEach(WriteCache.EntryConsumer consumer)
             throws java.io.IOException

Throws:

java.io.IOException

size

public long size()

count

public long count()

isEmpty

public boolean isEmpty()

align64

static int align64(int size)