LoggerSession

java.lang.Object
- xal.service.pvlogger.LoggerSession

```
public class LoggerSession
extends java.lang.Object
```
LoggerSession manages a session of logging machine state. One can create an instance to log the current machine state either on demand or periodically.

Field Summary

Fields
Modifier and Type	Field and Description
`protected boolean`	`_enabled`
`protected ChannelGroup`	`_group`
`protected MachineSnapshot`	`_latestMachineSnapshot` latest snapshot taken which may or may not have been published
`protected double`	`_loggingPeriod`
`protected java.util.TimerTask`	`_logTask`
`protected static double`	`DEFAULT_LOGGING_PERIOD` default logging period in seconds
`protected LoggerChangeListener`	`EVENT_PROXY`
`protected int`	`INITIAL_DELAY` initial timer delay
`protected java.util.Timer`	`LOG_TIMER`
`protected MessageCenter`	`MESSAGE_CENTER`
`protected xal.service.pvlogger.SnapshotPublisher`	`SNAPSHOT_PUBLISHER` publisher of snapshots to the persistent store

Constructor Summary

Constructors
Constructor and Description

LoggerSession(ChannelGroup group, xal.service.pvlogger.SnapshotPublisher publisher)
LoggerSession constructor

Constructors
Constructor and Description
`LoggerSession(ChannelGroup group, xal.service.pvlogger.SnapshotPublisher publisher)` LoggerSession constructor

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addLoggerChangeListener(LoggerChangeListener listener)` Add a logger change listener to receive logger change events.
`protected void`	`disposeLoggingTask()` dispose of the logging task
`ChannelGroup`	`getChannelGroup()` Get the active channel group for this session
`java.util.Collection<Channel>`	`getChannels()` Get the channels which we are attempting to monitor and log
`MachineSnapshot`	`getLatestMachineSnapshot()` Get the latest machine snapshot which may or may not have been published
`double`	`getLoggingPeriod()` Get the loggin period.
`boolean`	`isEnabled()` Determine whether this logger session is enabled
`boolean`	`isLogging()` Reveal whether the logger is scheduled to run periodically
`protected java.util.TimerTask`	`newLoggingTask()` get a new timer task for periodic logging
`void`	`publishSnapshot(MachineSnapshot machineSnapshot)` Publish the machine snapshot to the persistent storage.
`void`	`removeLoggerChangeListener(LoggerChangeListener listener)` Remove a logger change listener from receiving logger change events.
`void`	`resumeLogging()` Resume periodic logging with the most recent settings if enabled.
`void`	`setChannelGroup(ChannelGroup group)` Set the channel group for this logger session
`protected void`	`setEnabled(boolean enable)` Set whether this session should be enabled
`void`	`setLoggingPeriod(double period)` Set the period between events where we take and store machine snapshots.
`void`	`startLogging()` Start periodically logging machine state to the persistent storage.
`void`	`startLogging(double period)` Start periodically logging machine state to the persistent storage.
`void`	`stopLogging()` Stop the periodic machine state logging.
`MachineSnapshot`	`takeAndPublishSnapshot()` Take a snapshot and publish it immediately
`MachineSnapshot`	`takeAndPublishSnapshot(java.lang.String comment)` Take a snapshot and publish it immediately
`protected MachineSnapshot`	`takeAndScheduleSnapshotForPublication()` Take a snapshot and schedule it for publication
`MachineSnapshot`	`takeSnapshot()` Take a snapshot of the current machine state.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - INITIAL_DELAY
```
protected final int INITIAL_DELAY
```
    initial timer delay
    
    See Also:
    
    Constant Field Values
  - DEFAULT_LOGGING_PERIOD
```
protected static final double DEFAULT_LOGGING_PERIOD
```
    default logging period in seconds
    
    See Also:
    
    Constant Field Values
  - SNAPSHOT_PUBLISHER
```
protected xal.service.pvlogger.SnapshotPublisher SNAPSHOT_PUBLISHER
```
    publisher of snapshots to the persistent store
  - _latestMachineSnapshot
```
protected volatile MachineSnapshot _latestMachineSnapshot
```
    latest snapshot taken which may or may not have been published
  - MESSAGE_CENTER
```
protected final MessageCenter MESSAGE_CENTER
```
  - EVENT_PROXY
```
protected final LoggerChangeListener EVENT_PROXY
```
  - _group
```
protected ChannelGroup _group
```
  - LOG_TIMER
```
protected final java.util.Timer LOG_TIMER
```
  - _logTask
```
protected java.util.TimerTask _logTask
```
  - _loggingPeriod
```
protected double _loggingPeriod
```
  - _enabled
```
protected boolean _enabled
```
- Constructor Detail
  - LoggerSession
```
public LoggerSession(ChannelGroup group,
                     xal.service.pvlogger.SnapshotPublisher publisher)
```
    LoggerSession constructor
    
    Parameters:
    
    group - Group of channels to log.
    
    publisher - The snapshot publisher.
- Method Detail
  - addLoggerChangeListener
```
public void addLoggerChangeListener(LoggerChangeListener listener)
```
    Add a logger change listener to receive logger change events.
    
    Parameters:
    
    listener - The listener of the logger change events.
  - removeLoggerChangeListener
```
public void removeLoggerChangeListener(LoggerChangeListener listener)
```
    Remove a logger change listener from receiving logger change events.
    
    Parameters:
    
    listener - The listener of the logger change events.
  - resumeLogging
```
public void resumeLogging()
```
    Resume periodic logging with the most recent settings if enabled.
  - startLogging
```
public void startLogging()
```
    Start periodically logging machine state to the persistent storage.
  - startLogging
```
public void startLogging(double period)
```
    Start periodically logging machine state to the persistent storage.
    
    Parameters:
    
    period - The period in seconds between events where we take and store machine snapshots.
  - stopLogging
```
public void stopLogging()
```
    Stop the periodic machine state logging.
  - isLogging
```
public boolean isLogging()
```
    Reveal whether the logger is scheduled to run periodically
    
    Returns:
    
    true if the logger is scheduled to run periodically or false otherwise
  - setLoggingPeriod
```
public void setLoggingPeriod(double period)
```
    Set the period between events where we take and store machine snapshots.
    
    Parameters:
    
    period - The period in seconds between events where we take and store machine snapshots.
  - getLoggingPeriod
```
public double getLoggingPeriod()
```
    Get the loggin period.
    
    Returns:
    
    The period in seconds between events where we take and store machine snapshots.
  - isEnabled
```
public boolean isEnabled()
```
    Determine whether this logger session is enabled
    
    Returns:
    
    true if this logger session is enabled and false if not
  - setEnabled
```
protected void setEnabled(boolean enable)
```
    Set whether this session should be enabled
    
    Parameters:
    
    enable - true to enable this session and false to disable it
  - getChannelGroup
```
public ChannelGroup getChannelGroup()
```
    Get the active channel group for this session
    
    Returns:
    
    the channel group
  - setChannelGroup
```
public void setChannelGroup(ChannelGroup group)
```
    Set the channel group for this logger session
    
    Parameters:
    
    group - the new channel group for this logger session
  - getChannels
```
public java.util.Collection<Channel> getChannels()
```
    Get the channels which we are attempting to monitor and log
    
    Returns:
    
    a collection of the channels we wish to monitor and log
  - getLatestMachineSnapshot
```
public MachineSnapshot getLatestMachineSnapshot()
```
    Get the latest machine snapshot which may or may not have been published
    
    Returns:
    
    the latest machine snapshot
  - takeAndPublishSnapshot
```
public final MachineSnapshot takeAndPublishSnapshot()
```
    Take a snapshot and publish it immediately
    
    Returns:
    
    the published snapshot
  - takeAndPublishSnapshot
```
public final MachineSnapshot takeAndPublishSnapshot(java.lang.String comment)
```
    Take a snapshot and publish it immediately
    
    Parameters:
    
    comment - machine snapshot comment
    
    Returns:
    
    the published snapshot
  - takeAndScheduleSnapshotForPublication
```
protected final MachineSnapshot takeAndScheduleSnapshotForPublication()
```
    Take a snapshot and schedule it for publication
    
    Returns:
    
    the scheduled snapshot
  - takeSnapshot
```
public final MachineSnapshot takeSnapshot()
```
    Take a snapshot of the current machine state.
    
    Returns:
    
    A snapshot of the current machine state.
  - publishSnapshot
```
public final void publishSnapshot(MachineSnapshot machineSnapshot)
```
    Publish the machine snapshot to the persistent storage.
    
    Parameters:
    
    machineSnapshot - The machine snapshot to publish.
  - disposeLoggingTask
```
protected void disposeLoggingTask()
```
    dispose of the logging task
  - newLoggingTask
```
protected final java.util.TimerTask newLoggingTask()
```
    get a new timer task for periodic logging

Class LoggerSession

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

INITIAL_DELAY

DEFAULT_LOGGING_PERIOD

SNAPSHOT_PUBLISHER

_latestMachineSnapshot

MESSAGE_CENTER

EVENT_PROXY

_group

LOG_TIMER

_logTask

_loggingPeriod

_enabled

Constructor Detail

LoggerSession

Method Detail

addLoggerChangeListener

removeLoggerChangeListener

resumeLogging

startLogging

startLogging

stopLogging

isLogging

setLoggingPeriod

getLoggingPeriod

isEnabled

setEnabled

getChannelGroup

setChannelGroup

getChannels

getLatestMachineSnapshot

takeAndPublishSnapshot

takeAndPublishSnapshot

takeAndScheduleSnapshotForPublication

takeSnapshot

publishSnapshot

disposeLoggingTask

newLoggingTask