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

Classes
class	LogCacheInfo
Public Member Functions
synchronized int	getSize ()
long	getFileSize () throws IOException
synchronized void	clear () throws LogCacheException
synchronized ILogEntry	getLog (Integer key) throws LogCacheException
synchronized int	add (ILogEntry log) throws LogCacheException
void	replaceLog (Integer key, ILogEntry log) throws LogCacheException
synchronized void	deleteLog (Integer key) throws LogCacheException
synchronized void	deleteLogs (Collection< Integer > keys) throws LogCacheException
Integer	getFirstLog ()
int	getFirstLogs (int n, Collection< Integer > keys)
Integer	getLastLog ()
Set< Integer >	keySet ()
Iterator< ILogEntry >	iterator ()
Protected Member Functions
void	initCache () throws IOException
String	toCacheString (ILogEntry log)
Protected Attributes
RandomAccessFile	file = null
int	logID = 0
TreeMap< Integer, LogCacheInfo >	index = new TreeMap<Integer,LogCacheInfo>()
HashMap< Integer, ILogEntry >	replacedLogs = new HashMap<Integer,ILogEntry>()

Detailed Description

This class implements the cache in order to be able to manage long log files. It is implemented by a file of logs and a data structure to associate the position in a file (LogCacheInfo) to each log. Such data structure is realized by a TreeMap whith the key given by the (progressive, unique) number of a log.

Actually it is not possible to remove a log from the file. To effectively delete logs from disk we need some kind of garbage collector that removes the logs marked as delete from the file. This garbage collector is needed to avoid the file on disk grows indefinitely.

Another potential problem is given by the integer identifier of the logs that grows indefinitely. A temporary solution could be that of using long instad of integers.

Author:: acaproni

Member Function Documentation

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

Append a log to the end of the cache

Parameters:

log

The log to append in the cache

Returns:: The key in the cache of the added log

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

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

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

Empty the cache.

Exceptions:

IOException

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

References com.cosylab.logging.client.cache.LogFileCache.file, com.cosylab.logging.client.cache.LogFileCache.index, and com.cosylab.logging.client.cache.LogFileCache.logID.

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

Delete a log The log is marked as deleted and moved from the index to the deleteLogIndex. The log still exists in the file but is not accessible.

Parameters:

pos

The key of the log to remove

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

References com.cosylab.logging.client.cache.LogFileCache.index, com.cosylab.logging.client.cache.LogFileCache.logID, and com.cosylab.logging.client.cache.LogFileCache.replacedLogs.

Referenced by com.cosylab.logging.client.cache.LogFileCache.deleteLogs().

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

Delete a set of logs

Parameters:

keys

The keys of logs to delete

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

References com.cosylab.logging.client.cache.LogFileCache.deleteLog().

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

Return the length of the file on disk

Returns:: The size of the file cache

Exceptions:

IOException

in case of I/O error

See also:: java.io.RandomAccessFile

References com.cosylab.logging.client.cache.LogFileCache.file.

Integer com.cosylab.logging.client.cache.LogFileCache.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.

References com.cosylab.logging.client.cache.LogFileCache.index.

int com.cosylab.logging.client.cache.LogFileCache.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.

References com.cosylab.logging.client.cache.LogFileCache.index.

Integer com.cosylab.logging.client.cache.LogFileCache.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

Returns:: The key of the last inserted log null if th cache is empty

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

References com.cosylab.logging.client.cache.LogFileCache.index.

synchronized ILogEntry com.cosylab.logging.client.cache.LogFileCache.getLog ( Integer key ) throws LogCacheException

Return the log in the given position

Parameters:

pos

The position of the log

Returns:: The LogEntryXML or null in case of error

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

References com.cosylab.logging.client.cache.LogFileCache.index, com.cosylab.logging.client.cache.LogFileCache.logID, and com.cosylab.logging.client.cache.LogFileCache.replacedLogs.

synchronized int com.cosylab.logging.client.cache.LogFileCache.getSize ( )

Returns:: The number of logs in cache

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

References com.cosylab.logging.client.cache.LogFileCache.index.

void com.cosylab.logging.client.cache.LogFileCache.initCache ( ) throws IOException [protected]

Init the file where the cache stores the logs If the file already exists it is truncated to 0 length this situation might happen whenever the cache is cleared

Exceptions:

IOException

References com.cosylab.logging.client.cache.LogFileCache.file, com.cosylab.logging.client.cache.LogFileCache.index, and com.cosylab.logging.client.cache.LogFileCache.replacedLogs.

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

Iterator<ILogEntry> com.cosylab.logging.client.cache.LogFileCache.iterator ( )

Return an iterator over the logs in cache

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

Set<Integer> com.cosylab.logging.client.cache.LogFileCache.keySet ( )

Return a set with all the keys of the logs in cache

Returns:: The keys of the logs in cache

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

References com.cosylab.logging.client.cache.LogFileCache.index.

void com.cosylab.logging.client.cache.LogFileCache.replaceLog	(	Integer	key,
		ILogEntry	log
	)			throws LogCacheException

Replace the log in the given position with the new one NOTE: the new log is kept in memory

Parameters:

	position	The position of the log to replace
	log	The key (identifier) ot the log

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

References com.cosylab.logging.client.cache.LogFileCache.index, and com.cosylab.logging.client.cache.LogFileCache.replacedLogs.

String com.cosylab.logging.client.cache.LogFileCache.toCacheString ( ILogEntry log ) [protected]

References com.cosylab.logging.engine.log.ILogEntry.getAdditionalData(), com.cosylab.logging.engine.log.ILogEntry.getField(), and com.cosylab.logging.engine.log.ILogEntry.hasDatas().

Referenced by com.cosylab.logging.client.cache.LogFileCache.add(), com.cosylab.logging.client.cache.LogBufferedFileCache.add(), and com.cosylab.logging.client.cache.LogBufferedFileCache.replaceLog().

Member Data Documentation

RandomAccessFile com.cosylab.logging.client.cache.LogFileCache.file = null [protected]

The file of logs is accessed in a random way (the positions are stored in the index)

Referenced by com.cosylab.logging.client.cache.LogFileCache.add(), com.cosylab.logging.client.cache.LogFileCache.clear(), com.cosylab.logging.client.cache.LogBufferedFileCache.flushBuffer(), com.cosylab.logging.client.cache.LogFileCache.getFileSize(), and com.cosylab.logging.client.cache.LogFileCache.initCache().

TreeMap<Integer,LogCacheInfo> com.cosylab.logging.client.cache.LogFileCache.index = new TreeMap<Integer,LogCacheInfo>() [protected]

The index of the log is a SortedMap having the number identifying a log as key. Each entry is a LogCacheInfo containing the starting and ending position of the log in the file

int com.cosylab.logging.client.cache.LogFileCache.logID = 0 [protected]

Each log is identified by a unique integer used as key to get the log from the file (throw the index data structure) logID is incremented whenever a new log is added

NOTE: in this implementation this value is incremented without taking care of the logs deleted.

Referenced by com.cosylab.logging.client.cache.LogFileCache.add(), com.cosylab.logging.client.cache.LogBufferedFileCache.add(), com.cosylab.logging.client.cache.LogFileCache.clear(), com.cosylab.logging.client.cache.LogFileCache.deleteLog(), and com.cosylab.logging.client.cache.LogFileCache.getLog().

HashMap<Integer,ILogEntry> com.cosylab.logging.client.cache.LogFileCache.replacedLogs = new HashMap<Integer,ILogEntry>() [protected]

The logs replaced (for example the logs with some info added) They are usually a few so we keep them in memory

Referenced by com.cosylab.logging.client.cache.LogFileCache.deleteLog(), com.cosylab.logging.client.cache.LogFileCache.getLog(), com.cosylab.logging.client.cache.LogFileCache.initCache(), and com.cosylab.logging.client.cache.LogFileCache.replaceLog().

The documentation for this class was generated from the following file:

LogFileCache.java

All Classes Namespaces Files Functions Variables Enumerations Properties

com.cosylab.logging.client.cache.LogFileCache Class Reference

Classes

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Member Function Documentation

Member Data Documentation