com.cosylab.logging.client.cache

Class LogCache

java.lang.Object

com.cosylab.logging.client.cache.LogMultiFileCache

com.cosylab.logging.client.cache.LogCache

All Implemented Interfaces:

ILogMap

public class LogCache
extends LogMultiFileCache
implements ILogMap

The class extends the cache on file keeping a set of logs in memory to avoid to access the file for the most frequently accessed logs

The cache stores the logs into an HashMap using their indexes as keys. It also stores an array of times and level of logs to speed up the sorting done by the table.

Author:

acaproni

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	CACHESIZE_PROPERTY_NAME The name of the property to set the size of the cache.
static int	DEFAULT_CACHESIZE The default size of the buffer of logs

Fields inherited from class com.cosylab.logging.client.cache.LogMultiFileCache

DEFAULT_FILEMAXSIZE, FILEMAXSIZE_PROPERTY_NAME

Constructor Summary

Constructors

Constructor and Description
LogCache() Build a LogCache object
LogCache(int size) Build a logCache object of the given size

Method Summary

Modifier and Type	Method and Description
int	add(ILogEntry log) Adds a log in the cache.
void	clear() Empty the cache
void	deleteLog(java.lang.Integer key) Delete a log with the given key
void	deleteLogs(java.lang.Integer[] keys) Delete a collection of logs
int	getCacheSize() Gets the actual cache size, which may come from getDefaultCacheSize() or may be given in the constructor.
ILogEntry	getLog(java.lang.Integer key) Return the log with the given key.
java.util.Collection<java.lang.Integer>	getLogExceedingTimeFrame(long timeframe) Returns a set of number of logs (i.e.
java.lang.Long	getLogTimestamp(java.lang.Integer key)
LogTypeHelper	getLogType(java.lang.Integer key)
java.util.Calendar	getTimeFrame() Calculate and return the time frame of the logs managed by the GUI The time frame is the number of hours/minutes/seconds between the newest and the oldest log in the GUI I prefer to evaluate the frame instead of storing the min and max value because it works even if one log is deleted from the cache.
java.util.Iterator<ILogEntry>	iterator() Return an iterator over the logs in cache
java.util.Set<java.lang.Integer>	keySet() The keys in the map

Methods inherited from class com.cosylab.logging.client.cache.LogMultiFileCache

deleteLogs, getFilesSize, getFirstLog, getFirstLogs, getLastLog, getLogFileSize, getMaxFileSize, getNumberOfCacheFiles, getSize, printFileTableInfo, replaceLog, setDebugTrace

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.cosylab.logging.client.cache.ILogMap

deleteLogs, getFirstLog, getFirstLogs, getLastLog, getSize, replaceLog

Field Detail

CACHESIZE_PROPERTY_NAME

public static final java.lang.String CACHESIZE_PROPERTY_NAME

The name of the property to set the size of the cache. This is the size oif the logs buffered by LogCache

See Also:

Constant Field Values

DEFAULT_CACHESIZE

public static final int DEFAULT_CACHESIZE

The default size of the buffer of logs

See Also:

Constant Field Values

Constructor Detail

LogCache

public LogCache()
         throws LogCacheException

Build a LogCache object

Throws:

java.io.IOException - The exception is thrown if the base class is not able to create the cache on a file

LogCacheException

LogCache

public LogCache(int size)
         throws LogCacheException

Build a logCache object of the given size

Parameters:

size - The size of the cache

Throws:

LogCacheException

Method Detail

add

public int add(ILogEntry log)
        throws LogCacheException

Adds a log in the cache. It does nothing because the adding is done by its parent class. What it does is to store the level and time of the log in the arrays

Specified by:

add in interface ILogMap

Overrides:

add in class LogMultiFileCache

Parameters:

log - The log to add in the cache

Returns:

The key of the added log in the cache

Throws:

LogCacheException - If an error happened while adding the log

getLogType

public LogTypeHelper getLogType(java.lang.Integer key)
                         throws LogCacheException

Parameters:

pos - The key of the log

Returns:

The type of the log with the given key

Throws:

LogCacheException

getLogTimestamp

public java.lang.Long getLogTimestamp(java.lang.Integer key)
                               throws LogCacheException

Parameters:

pos - The key of the log

Returns:

The timestamp of the log with the given key

Throws:

LogCacheException

getLog

public ILogEntry getLog(java.lang.Integer key)
                 throws LogCacheException

Return the log with the given key. The method is synchronized because both the HashMap and the LinkedList must be synchronized if there is a chance to acces these objects from more then one thread in the same time

Specified by:

getLog in interface ILogMap

Overrides:

getLog in class LogMultiFileCache

Parameters:

pos - The key of the log

Returns:

The LogEntryXML or null in case of error

Throws:

LogCacheException

See Also:

LinkedList, HashMap

clear

public void clear()
           throws LogCacheException

Empty the cache

Specified by:

clear in interface ILogMap

Overrides:

clear in class LogMultiFileCache

Throws:

LogCacheException

See Also:

ILogMap

getCacheSize

public int getCacheSize()

Gets the actual cache size, which may come from getDefaultCacheSize() or may be given in the constructor.

Returns:

getTimeFrame

public java.util.Calendar getTimeFrame()

Calculate and return the time frame of the logs managed by the GUI The time frame is the number of hours/minutes/seconds between the newest and the oldest log in the GUI I prefer to evaluate the frame instead of storing the min and max value because it works even if one log is deleted from the cache.

Returns:

The time frame

deleteLog

public void deleteLog(java.lang.Integer key)
               throws LogCacheException

Delete a log with the given key

Specified by:

deleteLog in interface ILogMap

Overrides:

deleteLog in class LogMultiFileCache

Parameters:

pos - The key of the log to delete

Throws:

LogCacheException

deleteLogs

public void deleteLogs(java.lang.Integer[] keys)
                throws LogCacheException

Delete a collection of logs

Parameters:

keys - The keys of the logs to delete

Throws:

LogCacheException

getLogExceedingTimeFrame

public java.util.Collection<java.lang.Integer> getLogExceedingTimeFrame(long timeframe)

Returns a set of number of logs (i.e. their position in cache) exceeding the given time frame. This operation is quite slow because it requires a double scan of the logTimes array

Parameters:

timeframe - The time frame to check in millisecond

Returns:

A collection of number of logs exceedding the given timeframe

keySet

public java.util.Set<java.lang.Integer> keySet()

The keys in the map

Specified by:

keySet in interface ILogMap

Overrides:

keySet in class LogMultiFileCache

Returns:

The keys in the map

See Also:

ILogMap

iterator

public java.util.Iterator<ILogEntry> iterator()

Return an iterator over the logs in cache

Specified by:

iterator in interface ILogMap

Overrides:

iterator in class LogMultiFileCache

Returns:

an Iterator over the elements in this map

See Also:

ILogMap