Inheritance diagram for com.cosylab.logging.client.cache.LogBufferedFileCache:

Classes
class	BufferedCacheItem
Public Member Functions
	LogBufferedFileCache (int writeBufferSize) throws LogCacheException
	LogBufferedFileCache () throws LogCacheException
synchronized void	clear () throws LogCacheException
synchronized ILogEntry	getLog (Integer key) throws LogCacheException
synchronized void	deleteLog (Integer key) throws LogCacheException
synchronized void	deleteLogs (Collection< Integer > keys) throws LogCacheException
synchronized int	add (ILogEntry log) throws LogCacheException
void	flushBuffer () throws LogCacheException
synchronized int	getSize ()
long	getFileSize () throws IOException
synchronized final int	getBufferSize ()
Integer	getFirstLog ()
int	getFirstLogs (int n, Collection< Integer > keys)
Integer	getLastLog ()
Set< Integer >	keySet ()
Iterator< ILogEntry >	iterator ()
synchronized void	replaceLog (Integer key, ILogEntry log) throws LogCacheException
Static Public Attributes
static final String	WRITEBUFFERSIZE_PROPERTY_NAME = "jlog.cache.writebuffersize"
static final int	DEFAULT_WRITEBUFFERSIZE = 8192

Detailed Description

This class extends the LogFileCache adding the buffering of the logs that must be written on disk.

It uses a WriteBuffer to store the logs to write on disk. The purpose of this class is to write several logs at once reducing the write operations on disk.

The buffer stores the logs when they are added. It flushes the buffer on disk when the number of logs in memory exceeds the maximum size. This means that the number of chars written on the file cache at once is not fixed but depends on the lengths of the logs stored in this buffer. To enhance performance and to have the size of the file always available, the buffer stores the log together with other info in Map of BufferedCacheItem

Author:: acaproni

Constructor & Destructor Documentation

com.cosylab.logging.client.cache.LogBufferedFileCache.LogBufferedFileCache ( int writeBufferSize ) throws LogCacheException

Build a LogBufferedFileCache with the given size for the cache and the write buffer. If there isn't enough memory for the cache, tries with a smmaller size.

Parameters:

	cacheSize	The size of the cache
	writeBufferSize	The size of the write buffer

Exceptions:

LogCacheException

If there is'nt enough memory for a buffer of at least 32 logs

com.cosylab.logging.client.cache.LogBufferedFileCache.LogBufferedFileCache ( ) throws LogCacheException

Build a LogBufferedFileCache with the default sizes for the write buffer

Exceptions:

LogCacheException

See also:: LogBufferedFileCache.getDefaultWriteCacheSize

Member Function Documentation

synchronized int com.cosylab.logging.client.cache.LogBufferedFileCache.add ( ILogEntry log ) throws LogCacheException

Append a log to the cache

Parameters:

log

The log to append in the cache

Returns:: The key of the added log

Implements com.cosylab.logging.client.cache.ILogMap.

References com.cosylab.logging.client.cache.LogBufferedFileCache.flushBuffer(), com.cosylab.logging.client.cache.LogFileCache.logID, and com.cosylab.logging.client.cache.LogFileCache.toCacheString().

Referenced by com.cosylab.logging.client.cache.MultiFileTableRecord.addLog().

synchronized void com.cosylab.logging.client.cache.LogBufferedFileCache.clear ( ) throws LogCacheException

Empty the cache

Exceptions:

IOException

Implements com.cosylab.logging.client.cache.ILogMap.

Referenced by com.cosylab.logging.client.cache.MultiFileTableRecord.clear().

synchronized void com.cosylab.logging.client.cache.LogBufferedFileCache.deleteLog ( Integer key ) throws LogCacheException

Delete a log with the given key

Parameters:

pos

The key of the log to delete

Implements com.cosylab.logging.client.cache.ILogMap.

Referenced by com.cosylab.logging.client.cache.MultiFileTableRecord.deleteLog().

synchronized void com.cosylab.logging.client.cache.LogBufferedFileCache.deleteLogs ( Collection< Integer > keys ) throws LogCacheException

Delete a collection of logs

Parameters:

keys

The keys of the logs to remove from the cache

Implements com.cosylab.logging.client.cache.ILogMap.

void com.cosylab.logging.client.cache.LogBufferedFileCache.flushBuffer ( ) throws LogCacheException

Flush all the logs on file

References com.cosylab.logging.client.cache.LogFileCache.file, com.cosylab.logging.client.cache.LogFileCache.index, and com.cosylab.logging.client.cache.LogFileCache.initCache().

Referenced by com.cosylab.logging.client.cache.LogBufferedFileCache.add(), and com.cosylab.logging.client.cache.MultiFileTableRecord.flushBuffer().

synchronized final int com.cosylab.logging.client.cache.LogBufferedFileCache.getBufferSize ( )

Returns:: The number of logs actually in the buffer

long com.cosylab.logging.client.cache.LogBufferedFileCache.getFileSize ( ) throws IOException

Return the length of the file on disk taking into account the length of the string to write on the disk for the logs in the buffer.

Returns:: The size of the file cache

Exceptions:

IOException

in case of I/O error

See also:: java.io.RandomAccessFile

Referenced by com.cosylab.logging.client.cache.MultiFileTableRecord.getFileSize().

Integer com.cosylab.logging.client.cache.LogBufferedFileCache.getFirstLog ( )

Return the key of the first valid log (FIFO). The key of the first log is 0 but it can change if the log 0 has been deleted.

Returns:: The key of the first log null if the cache is empty

Implements com.cosylab.logging.client.cache.ILogMap.

Referenced by com.cosylab.logging.client.cache.MultiFileTableRecord.getFirstLog().

int com.cosylab.logging.client.cache.LogBufferedFileCache.getFirstLogs	(	int	n,
		Collection< Integer >	keys
	)

Append at most n keys from the first valid logs to the collection. First here means first in the FIFO policy.

The number of added keys can be less then n if the cache doesn't contain enough logs.

Parameters:

	n	The desired number of keys of first logs
	keys	The collection to add they keys to

Returns:: The number of keys effectively added

Implements com.cosylab.logging.client.cache.ILogMap.

Referenced by com.cosylab.logging.client.cache.MultiFileTableRecord.getFirstLogs().

Integer com.cosylab.logging.client.cache.LogBufferedFileCache.getLastLog ( )

Return the key of the last valid log (FIFO) The key of the last log is the key of the last inserted log but it can cheang if such log has been deleted