com.cosylab.logging.engine.ACS

Class ACSLogRetrieval

java.lang.Object

com.cosylab.logging.engine.LogMatcher

com.cosylab.logging.engine.ACS.ACSLogRetrieval

All Implemented Interfaces:

java.lang.Runnable

public class ACSLogRetrieval
extends LogMatcher
implements java.lang.Runnable

ACSLogRetrieval stores the XML string (or a String in case of binary logs) representing logs on a file when the engine is not able to follow the flow of the incoming logs The strings are stored on disk and the logs published to the listeners when there is enough CPU available.

ACSLogRetrieval allows to set the rate (i.e. number of logs per second) for the logs to receive and push in cache. All the logs received after this limit has been reached are discarded regardless of their content. This option must be used very carefully because can cause loss of logs.

It also allows to set the rate i.e. number of logs per second) for the logs read from the cache and published to listener. When the limit has been reached, no logs are pushed anymore out of the cache until the current second has elapsed. This limitation must be used very carefully because it can cause a uncontrolled growth of the cache that could lead to an out of memory.
By default, the input and output rates are unlimited (Integer.MAX_VALUE)

The available memory is checked every second. To avoid out of memory the user can enable the dynamic discarding by giving a threshold (in bytes). If a threshold is defined, the thread that checks the amount of available memory increases the discard level. To avoid oscillations, the user can define a a damping factor: the discard level is decreased when the amount of available memory is greater the the threshold plus the damping.

Life cycle: start() must be called at the beginning and #stop() at the end. *

See Also:

ACSRemoteLogListener, ACSRemoteRawLogListener, ACSLogConnectionListener

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	ACSLogRetrieval.RateUpdater

Field Summary

Fields inherited from class com.cosylab.logging.engine.LogMatcher

actualDiscardLevel

Constructor Summary

Constructors

Constructor and Description
ACSLogRetrieval(ACSListenersDispatcher listenersDispatcher) Constructor
ACSLogRetrieval(ACSListenersDispatcher listenersDispatcher, boolean binFormat, FiltersVector filters) Constructor
ACSLogRetrieval(ACSListenersDispatcher listenersDispatcher, boolean binFormat, FiltersVector filters, IResourceChecker resCecker) A construct that allow passing a ResourceChecker.
ACSLogRetrieval(ACSListenersDispatcher listenersDispatcher, TimestampedStringQueueFileHandler fileHandler) Constructor

Method Summary

Modifier and Type	Method and Description
void	addLog(java.lang.String XMLLogStr) Add a log in the file
void	close(boolean sync) Close the threads and free all the resources
void	enableDynamicDiscarding(int threshold, int damping, int interval) Enable dynamic discarding of incoming logs.
LogTypeHelper	getDiscardLevel() Return the discard level set by the user
int	getInputRate() Return the number of strings received in the last second.
int	getMaxInputRate()
int	getMaxOutputRate()
int	getOutputRate() Return the number of strings read from the cache in the last second limited.
boolean	hasPendingEntries() Check if there are logs to be published in the cache.
void	pause(boolean pause) Pause/unpause the thread that publishes logs
void	run() The thread to read and notify the logs read from the file to the listeners
void	setDiscardLevel(LogTypeHelper newLevel) Set the discard level
void	setMaxInputRate(int maxInRate) Set the max number of logs to process per second.
void	setMaxOutputRate(int maxOutRate) Set the max number of logs to read from the cache per second.
int	size() Return the number of entries in the cache
void	start() Init the file and the parser

Methods inherited from class com.cosylab.logging.engine.LogMatcher

getActualDiscardLevel, getAudience, getFilters, match, setAudience, setFilters

Methods inherited from class java.lang.Object

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

Constructor Detail

ACSLogRetrieval

public ACSLogRetrieval(ACSListenersDispatcher listenersDispatcher)

Constructor

Parameters:

listenersDispatcher - The object to send messages to the listeners Can't be null

ACSLogRetrieval

public ACSLogRetrieval(ACSListenersDispatcher listenersDispatcher,
                       TimestampedStringQueueFileHandler fileHandler)

Constructor

Parameters:

listenersDispatcher - The not null object to send messages to the listeners

The - fileHandler the files of the cache

ACSLogRetrieval

public ACSLogRetrieval(ACSListenersDispatcher listenersDispatcher,
                       boolean binFormat,
                       FiltersVector filters)

Constructor

Parameters:

listenersDispatcher - The object to send messages to the listeners Can't be null

binFormat - true if the lags are binary, false if XML format is used

filters - The filters to apply to incoming logs If null or empty no filters are applied

ACSLogRetrieval

public ACSLogRetrieval(ACSListenersDispatcher listenersDispatcher,
                       boolean binFormat,
                       FiltersVector filters,
                       IResourceChecker resCecker)

A construct that allow passing a ResourceChecker.

This is mostly intended for testing purposes to simulate overloading or memory consumption.

Parameters:

listenersDispatcher - The object to send messages to the listeners Can't be null

binFormat - true if the lags are binary, false if XML format is used

filters - The filters to apply to incoming logs If null or empty no filters are applied

roCecher -

Method Detail

start

public void start()
           throws LogEngineException

Init the file and the parser

Throws:

LogEngineException

addLog

public void addLog(java.lang.String XMLLogStr)

Add a log in the file

Parameters:

XMLLogStr - The XML string of the new log to add

run

public void run()

The thread to read and notify the logs read from the file to the listeners

Specified by:

run in interface java.lang.Runnable

pause

public void pause(boolean pause)

Pause/unpause the thread that publishes logs

Parameters:

pause -

close

public void close(boolean sync)

Close the threads and free all the resources

Parameters:

sync - If it is true wait the termination of the threads before returning

hasPendingEntries

public boolean hasPendingEntries()

Check if there are logs to be published in the cache.

Returns:

true if there are logs to be processed in the file

size

public int size()

Return the number of entries in the cache

Returns:

the number of entries in the cache

getInputRate

public int getInputRate()

Return the number of strings received in the last second. Note that the number of received strings can be greater then the max number of input strings.

Returns:

The number of strings received in the last second

getOutputRate

public int getOutputRate()

Return the number of strings read from the cache in the last second limited. It can never be greater then the max rate.

Returns:

The number of strings read from the cache in the last second

getMaxInputRate

public int getMaxInputRate()

Returns:

The max number of strings pushed in the cache per second

setMaxInputRate

public void setMaxInputRate(int maxInRate)

Set the max number of logs to process per second.

All the logs in a second read after this number has been reached are discarded i.e. never pushed in the cache.

Parameters:

maxInRate - The max number of logs per second to push in cache. Integer.MAX_VALUE means unlimited

getMaxOutputRate

public int getMaxOutputRate()

Returns:

The maximum number of logs published per second

setMaxOutputRate

public void setMaxOutputRate(int maxOutRate)

Set the max number of logs to read from the cache per second.

All the logs in a second read after this number has been reached are discarded i.e. never published to listeners.

Parameters:

maxOutRate - The max number of logs per second to read from cache. Integer.MAX_VALUE means unlimited

enableDynamicDiscarding

public void enableDynamicDiscarding(int threshold,
                                    int damping,
                                    int interval)

Enable dynamic discarding of incoming logs.

Parameters:

threashold - The discard level is increased when the available memory for the application is less then the threshold (in bytes). Integer.MAX_VALUE disables this feature.

damping - The damping factor is used to avoid oscillations The discard level is decreased when the free memory is is greater then the threshold plus the dumping.

interval - The time (in seconds) between two adjustments of the dynamic discard level. interval defaults to 10.

See Also:

setDiscardLevel(LogTypeHelper newLevel)

setDiscardLevel

public void setDiscardLevel(LogTypeHelper newLevel)

Set the discard level

Note: if dynamic filtering by memory is enabled then the discard level effectively used can be greater then this value.

Overrides:

setDiscardLevel in class LogMatcher

Parameters:

newLevel - The new discard level (null means no discard level).

See Also:

enableDynamicDiscarding(int threashold), getDiscardLevel()

getDiscardLevel

public LogTypeHelper getDiscardLevel()

Return the discard level set by the user

Returns:

the discardLevel

See Also:

etDiscardLevel(LogTypeHelper newLevel)