alma.acs.logging.engine

Class LogReceiver

java.lang.Object

alma.acs.logging.engine.LogReceiver

public class LogReceiver
extends java.lang.Object

Receives log messages from the ACS Log service and sorts them by timestamp, even if the log messages arrive in different order within a certain time window.

For a client of this class to consume these log messages, method getLogQueue() provides a BlockingQueue from which the client can extract the messages.

Before log messages can be received, #initialize(ORB, Manager) must be called. To disconnect from the the log stream, call stop().

As an alternative to getLogQueue and stop, this class also offers the method pair startCaptureLogs(PrintWriter) and stopCaptureLogs(). These methods can be used to directly print the received log messages to some writer, sparing the effort of listening on the LogQueue. Method stopCaptureLogs() must be called in that case to stop capturing logs.

Author:

hsommer

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	LogReceiver.DelayedLogEntry Wraps an ILogEntry for storage in a DelayQueue.
static class	LogReceiver.ReceivedLogRecord A jlog-independent representation of the log record we received

Field Summary

Fields

Modifier and Type	Field and Description
protected LCEngine	lct
protected alma.acs.logging.engine.LogReceiver.MyRemoteResponseCallback	rrc

Constructor Summary

Constructors

Constructor and Description
LogReceiver()

Method Summary

Modifier and Type	Method and Description
long	getDelayMillis()
java.util.concurrent.BlockingQueue<LogReceiver.DelayedLogEntry>	getLogQueue() Gets access to the log record queue, from which the time-sorted log records should be fetched.
java.lang.String[]	getStatusReports() Gets the status reports.
boolean	initialize() Initializes the connection to the logging channel, which leads to log entries getting written to the sorting queue.
boolean	initialize(org.omg.CORBA.ORB theORB, Manager manager, int timeoutSeconds) Variant of initialize() which takes an existing ORB and manager reference.
boolean	isInitialized()
boolean	isVerbose()
void	setDelayMillis(long newDelayMillis) Sets the delay that a log record's timestamp must have with respect to the current system time in order to be allowed to leave the sorting queue.
void	setVerbose(boolean verbose)
void	startCaptureLogs(java.io.PrintWriter logWriter) Convenience method to capture logs directly into a PrintWriter.
void	startCaptureLogs(java.io.PrintWriter logWriter, java.util.concurrent.ThreadFactory threadFactory) Variant of startCaptureLogs(PrintWriter) which takes an optional ThreadFactory which will be used to create the thread that reads out the log queue.
void	stop() Disconnects from the logging channel.
void	stopCaptureLogs() Stops capturing logs into the PrintWriter that was provided to startCaptureLogs(PrintWriter) or any of the related methods.

Methods inherited from class java.lang.Object

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

Field Detail

lct

protected LCEngine lct

rrc

protected alma.acs.logging.engine.LogReceiver.MyRemoteResponseCallback rrc

Constructor Detail

LogReceiver

public LogReceiver()

Method Detail

isVerbose

public boolean isVerbose()

setVerbose

public void setVerbose(boolean verbose)

initialize

public boolean initialize()
                   throws LogEngineException

Initializes the connection to the logging channel, which leads to log entries getting written to the sorting queue. To reuse an existing ORB and manager reference, use #initialize(ORB, Manager) instead of this method.

This method attempts to wait for successful initialization for up to 10 seconds. If initialization did not happen within this time, false is returned, otherwise true.

If you call this method, make sure to subsequently call getLogQueue() and drain the queue at your own responsibility, or to call startCaptureLogs(PrintWriter) (or startCaptureLogs(PrintWriter, ThreadFactory)) which will drain the queue automatically.

Returns:

true if initialization was successful within at most 10 seconds

Throws:

LogEngineException - In case of error instantiating the LCEngine

See Also:

initialize(ORB, Manager, int)

initialize

public boolean initialize(org.omg.CORBA.ORB theORB,
                          Manager manager,
                          int timeoutSeconds)
                   throws LogEngineException

Variant of initialize() which takes an existing ORB and manager reference.

This method attempts to wait for successful initialization for up to timeoutSeconds seconds. If initialization did not happen within this time, false is returned, otherwise true.

Parameters:

theORB - the fully functional ORB object to reuse, or null if an ORB should be created

manager - reference to the acs manager, or null if this reference should be created

timeoutSeconds - timeout for awaiting the successful initialization.

Returns:

true if initialization was successful within at most timeoutSeconds seconds.

Throws:

LogEngineException - In case of error instantiating the LCEngine

isInitialized

public boolean isInitialized()

setDelayMillis

public void setDelayMillis(long newDelayMillis)

Sets the delay that a log record's timestamp must have with respect to the current system time in order to be allowed to leave the sorting queue.

Parameters:

newDelayMillis - the delay time in milliseconds.

getDelayMillis

public long getDelayMillis()

getLogQueue

public java.util.concurrent.BlockingQueue<LogReceiver.DelayedLogEntry> getLogQueue()

Gets access to the log record queue, from which the time-sorted log records should be fetched.

The queue elements are of type LogReceiver.DelayedLogEntry, from which the log record can be extracted using the method LogReceiver.DelayedLogEntry.getLogEntry().

Returns:

getStatusReports

public java.lang.String[] getStatusReports()

Gets the status reports. Currently only a forceful disconnect would be shown, the rest is ignored. TODO: separate good and bad status reports

Returns:

stop

public void stop()

Disconnects from the logging channel. A special "queue poison" version of DelayedLogEntry will be added to the queue with zero delay, so that all clients who fetch log recored of the queue obtained from getLogQueue() know that the show is over.

See Also:

LogReceiver.DelayedLogEntry.isQueuePoison()

startCaptureLogs

public void startCaptureLogs(java.io.PrintWriter logWriter)
                      throws java.io.IOException

Convenience method to capture logs directly into a PrintWriter. Method #initialize(ORB, Manager) must be called as a precondition. Method stopCaptureLogs() must be called to stop writing logs to logWriter.

Parameters:

logWriter -

Throws:

java.io.IOException

startCaptureLogs

public void startCaptureLogs(java.io.PrintWriter logWriter,
                             java.util.concurrent.ThreadFactory threadFactory)
                      throws java.io.IOException

Variant of startCaptureLogs(PrintWriter) which takes an optional ThreadFactory which will be used to create the thread that reads out the log queue. This method could be used if LogReceiver is run inside a container or as part of a ComponentClientTestCase.

Throws:

java.io.IOException

stopCaptureLogs

public void stopCaptureLogs()

Stops capturing logs into the PrintWriter that was provided to startCaptureLogs(PrintWriter) or any of the related methods. Even though the call to this method returns immediately, all log records that are currently residing inside the queue will still be written out, waiting the due time to allow sorting them.