[#BloombergLP-ball-FileObserver2]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/ball.adoc[ball]::FileObserver2
:relfileprefix: ../../
:mrdocs:

Observer that publishes log records to a user‐specified file.

== Synopsis

Declared in `<ball_fileobserver2.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
class FileObserver2
    : public xref:BloombergLP/ball/Observer.adoc[Observer]
----

== Description

This class implements the `Observer` protocol. The `publish` method of this class outputs the log records that it receives to a user‐specified file. This class is thread‐safe; different threads can operate on an object concurrently. This class is exception‐neutral with no guarantee of rollback. In no event is memory leaked.

== Base Classes

[cols="1,4"]
|===
| Name| Description
| `xref:BloombergLP/ball/Observer.adoc[Observer]`
| This class provides a protocol for receiving and processing log record output.
|===

== Type Aliases

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/ball/FileObserver2/LogRecordFunctor.adoc[`LogRecordFunctor`] 
| `LogRecordFunctor` is an alias for the type of the functor used for formatting log records to a stream.
| xref:BloombergLP/ball/FileObserver2/OnFileRotationCallback.adoc[`OnFileRotationCallback`] 
| Callback invoked after each attempt to rotate the log file.
| xref:BloombergLP/ball/FileObserver2/RecordFormatter.adoc[`RecordFormatter`] 
| `RecordFormatter` is an alias for the type of the functor used for formatting log records to a stream.
|===


== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/ball/FileObserver2/2constructor.adoc[`FileObserver2`]         [.small]#[constructor]#
| Create a file observer with file logging initially disabled.
| xref:BloombergLP/ball/FileObserver2/2destructor.adoc[`~FileObserver2`] [.small]#[destructor]# [.small]#[virtual]#
| Close the log file of this file observer if file logging is enabled, and destroy this file observer.
| xref:BloombergLP/ball/FileObserver2/disableFileLogging.adoc[`disableFileLogging`] 
| Disable file logging for this file observer.
| xref:BloombergLP/ball/FileObserver2/disableLifetimeRotation.adoc[`disableLifetimeRotation`] 
| Disable log file rotation based on a periodic time interval for this file observer. This method has no effect if rotation‐on‐time‐interval is not enabled.
| xref:BloombergLP/ball/FileObserver2/disablePublishInLocalTime.adoc[`disablePublishInLocalTime`] 
| Disable publishing of record timestamps in local time.
| xref:BloombergLP/ball/FileObserver2/disableSizeRotation.adoc[`disableSizeRotation`] 
| Disable log file rotation based on log file size for this file observer. This method has no effect if rotation‐on‐size is not enabled.
| xref:BloombergLP/ball/FileObserver2/disableTimeIntervalRotation.adoc[`disableTimeIntervalRotation`] 
| Disable log file rotation based on a periodic time interval for this file observer. This method has no effect if rotation‐on‐time‐interval is not enabled.
| xref:BloombergLP/ball/FileObserver2/enableFileLogging-0b.adoc[`enableFileLogging`] 
| `enableFileLogging` overloads
| xref:BloombergLP/ball/FileObserver2/enablePublishInLocalTime.adoc[`enablePublishInLocalTime`] 
| Enable publishing of record timestamps in local time.
| xref:BloombergLP/ball/FileObserver2/forceRotation.adoc[`forceRotation`] 
| Force an immediate log file rotation by this observer.
| xref:BloombergLP/ball/FileObserver2/getFormat.adoc[`getFormat`] 
| Return the format config of the last successful `setFormat` call.
| xref:BloombergLP/ball/FileObserver2/isFileLoggingEnabled-00.adoc[`isFileLoggingEnabled`] 
| `isFileLoggingEnabled` overloads
| xref:BloombergLP/ball/FileObserver2/isPublishInLocalTimeEnabled.adoc[`isPublishInLocalTimeEnabled`] 
| Return `true` if published timestamps are written in local time.
| xref:BloombergLP/ball/FileObserver2/isSuppressUniqueFileNameOnRotation.adoc[`isSuppressUniqueFileNameOnRotation`] 
| Return `true` if the log filename uniqueness check on rotation is suppressed, and false otherwise.
| xref:BloombergLP/ball/FileObserver2/localTimeOffset.adoc[`localTimeOffset`] 
| Return the local‐minus‐UTC offset captured at construction.
| xref:BloombergLP/ball/FileObserver2/publish-09.adoc[`publish`] 
| Publish the specified log `record` with the given `context`.
| xref:BloombergLP/ball/FileObserver2/releaseRecords.adoc[`releaseRecords`]  [.small]#[virtual]#
| Discard shared references to published `Record` objects held by this observer.
| xref:BloombergLP/ball/FileObserver2/rotateOnLifetime.adoc[`rotateOnLifetime`] 
| Configure periodic log file rotation at the specified `timeInterval`.
| xref:BloombergLP/ball/FileObserver2/rotateOnSize.adoc[`rotateOnSize`] 
| Rotate the log file when its size exceeds the specified `size`.
| xref:BloombergLP/ball/FileObserver2/rotateOnTimeInterval-0b.adoc[`rotateOnTimeInterval`] 
| `rotateOnTimeInterval` overloads
| xref:BloombergLP/ball/FileObserver2/rotationLifetime.adoc[`rotationLifetime`] 
| Return the log file lifetime that triggers rotation, or zero.
| xref:BloombergLP/ball/FileObserver2/rotationSize.adoc[`rotationSize`] 
| Return the size (in kilobytes) of the log file that will trigger a file rotation by this file observer if rotation‐on‐size is in effect, and 0 otherwise.
| xref:BloombergLP/ball/FileObserver2/setFormat.adoc[`setFormat`] 
| Set the log‐file record format from the specified `format` string.
| xref:BloombergLP/ball/FileObserver2/setLogFileFunctor.adoc[`setLogFileFunctor`] 
| Set the formatting functor used when writing records to the log file.
| xref:BloombergLP/ball/FileObserver2/setOnFileRotationCallback.adoc[`setOnFileRotationCallback`] 
| Set the callback invoked after each log file rotation attempt.
| xref:BloombergLP/ball/FileObserver2/suppressUniqueFileNameOnRotation.adoc[`suppressUniqueFileNameOnRotation`] 
| Suppress or enable unique filenames when rotating the log file.
| xref:BloombergLP/ball/FileObserver2/2conversion.adoc[`operator BloombergLP::bslmf::NestedTraitDeclaration<FileObserver2, UsesBslmaAllocator>`] 
| Declare that this type uses a `bslma` allocator.
|===



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