- java.lang.Object
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- jdk.jfr.Recording
 
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- All Implemented Interfaces:
- Closeable,- AutoCloseable
 
 public final class Recording extends Object implements Closeable Provides means to configure, start, stop and dump recording data to disk.The following example shows how configure, start, stop and dump recording data to disk. Configuration c = Configuration.getConfiguration("default"); Recording r = new Recording(c); r.start(); System.gc(); Thread.sleep(5000); r.stop(); r.copyTo(Files.createTempFile("my-recording", ".jfr"));- Since:
- 9
 
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Method SummaryAll Methods Instance Methods Concrete Methods Modifier and Type Method Description voidclose()Releases all data that is associated with this recording.Recordingcopy(boolean stop)Returns a clone of this recording, with a new recording ID and name.EventSettingsdisable(Class<? extends Event> eventClass)Disables event.EventSettingsdisable(String name)Disables event with the specified name.voiddump(Path destination)Writes recording data to a file.EventSettingsenable(Class<? extends Event> eventClass)Enables event.EventSettingsenable(String name)Enables the event with the specified name.PathgetDestination()Returns the destination file, where recording data is written when the recording stops, ornullif no destination is set.booleangetDumpOnExit()Returns whether this recording is dumped to disk when the JVM exits.DurationgetDuration()Returns the specified duration for this recording, ornullif no duration is set.longgetId()Returns a unique ID for this recording.DurationgetMaxAge()Returns the length of time that the data is kept in the disk repository before it is removed.longgetMaxSize()Returns the maximum size, measured in bytes, at which data is no longer kept in the disk repository.StringgetName()Returns the name of this recording.Map<String,String>getSettings()Returns settings used by this recording.longgetSize()Returns the current size of this recording in the disk repository, measured in bytes.InstantgetStartTime()Returns the time when this recording was started.RecordingStategetState()Returns the recording state that this recording is currently in.InstantgetStopTime()Returns the time when this recording was stopped.InputStreamgetStream(Instant start, Instant end)Creates a data stream for a specified interval.booleanisToDisk()Returnstrueif this recording uses the disk repository,falseotherwise.voidscheduleStart(Duration delay)Starts this recording after a delay.voidsetDestination(Path destination)Sets a location where data is written on recording stop, ornullif data is not to be dumped.voidsetDumpOnExit(boolean dumpOnExit)Sets whether this recording is dumped to disk when the JVM exits.voidsetDuration(Duration duration)Sets a duration for how long a recording runs before it stops.voidsetMaxAge(Duration maxAge)Determines how far back data is kept in the disk repository.voidsetMaxSize(long maxSize)Determines how much data is kept in the disk repository.voidsetName(String name)Sets a human-readable name (for example,"My Recording").voidsetSettings(Map<String,String> settings)Replaces all settings for this recording.voidsetToDisk(boolean disk)Determines whether this recording is continuously flushed to the disk repository or data is constrained to what is available in memory buffers.voidstart()Starts this recording.booleanstop()Stops this recording.
 
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Constructor Detail- 
Recordingpublic Recording() Creates a recording without any settings.A newly created recording is in the RecordingState.NEWstate. To start the recording, invoke thestart()method.- Throws:
- IllegalStateException- if Flight Recorder can't be created (for example, if the Java Virtual Machine (JVM) lacks Flight Recorder support, or if the file repository can't be created or accessed)
- SecurityException- If a security manager is used and FlightRecorderPermission "accessFlightRecorder" is not set.
 
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Recordingpublic Recording(Configuration configuration) Creates a recording with settings from a configuration.The following example shows how create a recording that uses a predefined configuration. 
 The newly created recording is in theRecording r = new Recording(Configuration.getConfiguration("default"));RecordingState.NEWstate. To start the recording, invoke thestart()method.- Parameters:
- configuration- configuration that contains the settings to be use, not- null
- Throws:
- IllegalStateException- if Flight Recorder can't be created (for example, if the Java Virtual Machine (JVM) lacks Flight Recorder support, or if the file repository can't be created or accessed)
- SecurityException- if a security manager is used and FlightRecorderPermission "accessFlightRecorder" is not set.
- See Also:
- Configuration
 
 
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Method Detail- 
startpublic void start() Starts this recording.It's recommended that the recording options and event settings are configured before calling this method. The benefits of doing so are a more consistent state when analyzing the recorded data, and improved performance because the configuration can be applied atomically. After a successful invocation of this method, this recording is in the RUNNINGstate.- Throws:
- IllegalStateException- if recording is already started or is in the- CLOSEDstate
 
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scheduleStartpublic void scheduleStart(Duration delay) Starts this recording after a delay.After a successful invocation of this method, this recording is in the DELAYEDstate.- Parameters:
- delay- the time to wait before starting this recording, not- null
- Throws:
- IllegalStateException- if the recording is not it the- NEWstate
 
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stoppublic boolean stop() Stops this recording.When a recording is stopped it can't be restarted. If this recording has a destination, data is written to that destination and the recording is closed. After a recording is closed, the data is no longer available. After a successful invocation of this method, this recording will be in the STOPPEDstate.- Returns:
- trueif recording is stopped,- falseotherwise
- Throws:
- IllegalStateException- if the recording is not started or is already stopped
- SecurityException- if a security manager exists and the caller doesn't have- FilePermissionto write to the destination path
- See Also:
- setDestination(Path)
 
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getSettingspublic Map<String,String> getSettings() Returns settings used by this recording.Modifying the returned Mapwill not change the settings for this recording.If no settings are set for this recording, an empty Mapis returned.- Returns:
- recording settings, not null
 
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getSizepublic long getSize() Returns the current size of this recording in the disk repository, measured in bytes.The size is updated when recording buffers are flushed. If the recording is not written to the disk repository the returned size is always 0.- Returns:
- amount of recorded data, measured in bytes, or 0if the recording is not written to the disk repository
 
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getStopTimepublic Instant getStopTime() Returns the time when this recording was stopped.- Returns:
- the time, or nullif this recording is not stopped
 
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getStartTimepublic Instant getStartTime() Returns the time when this recording was started.- Returns:
- the the time, or nullif this recording is not started
 
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getMaxSizepublic long getMaxSize() Returns the maximum size, measured in bytes, at which data is no longer kept in the disk repository.- Returns:
- maximum size in bytes, or 0if no maximum size is set
 
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getMaxAgepublic Duration getMaxAge() Returns the length of time that the data is kept in the disk repository before it is removed.- Returns:
- maximum length of time, or nullif no maximum length of time has been set
 
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getNamepublic String getName() Returns the name of this recording.By default, the name is the same as the recording ID. - Returns:
- the recording name, not null
 
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setSettingspublic void setSettings(Map<String,String> settings) Replaces all settings for this recording.The following example shows how to set event settings for a recording. 
 The following example shows how to merge settings.Map<String, String> settings = new HashMap<>(); settings.putAll(EventSettings.enabled("jdk.CPUSample").withPeriod(Duration.ofSeconds(2)).toMap()); settings.putAll(EventSettings.enabled(MyEvent.class).withThreshold(Duration.ofSeconds(2)).withoutStackTrace().toMap()); settings.put("jdk.ExecutionSample#period", "10 ms"); recording.setSettings(settings);Map<String, String> settings = recording.getSettings(); settings.putAll(additionalSettings); recording.setSettings(settings);- Parameters:
- settings- the settings to set, not- null
 
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getStatepublic RecordingState getState() Returns the recording state that this recording is currently in.- Returns:
- the recording state, not null
- See Also:
- RecordingState
 
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closepublic void close() Releases all data that is associated with this recording.After a successful invocation of this method, this recording is in the CLOSEDstate.- Specified by:
- closein interface- AutoCloseable
- Specified by:
- closein interface- Closeable
 
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copypublic Recording copy(boolean stop) Returns a clone of this recording, with a new recording ID and name. Clones are useful for dumping data without stopping the recording. After a clone is created, the amount of data to copy is constrained with thesetMaxAge(Duration)method and thesetMaxSize(long)method.- Parameters:
- stop-- trueif the newly created copy should be stopped immediately,- falseotherwise
- Returns:
- the recording copy, not null
 
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dumppublic void dump(Path destination) throws IOException Writes recording data to a file.Recording must be started, but not necessarily stopped. - Parameters:
- destination- the location where recording data is written, not- null
- Throws:
- IOException- if the recording can't be copied to the specified location
- SecurityException- if a security manager exists and the caller doesn't have- FilePermissionto write to the destination path
 
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isToDiskpublic boolean isToDisk() Returnstrueif this recording uses the disk repository,falseotherwise.If no value is set, trueis returned.- Returns:
- trueif the recording uses the disk repository,- falseotherwise
 
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setMaxSizepublic void setMaxSize(long maxSize) Determines how much data is kept in the disk repository.To control the amount of recording data that is stored on disk, the maximum amount of data to retain can be specified. When the maximum limit is exceeded, the Java Virtual Machine (JVM) removes the oldest chunk to make room for a more recent chunk. If neither maximum limit or the maximum age is set, the size of the recording may grow indefinitely. - Parameters:
- maxSize- the amount of data to retain,- 0if infinite
- Throws:
- IllegalArgumentException- if- maxSizeis negative
- IllegalStateException- if the recording is in- CLOSEDstate
 
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setMaxAgepublic void setMaxAge(Duration maxAge) Determines how far back data is kept in the disk repository.To control the amount of recording data stored on disk, the maximum length of time to retain the data can be specified. Data stored on disk that is older than the specified length of time is removed by the Java Virtual Machine (JVM). If neither maximum limit or the maximum age is set, the size of the recording may grow indefinitely. - Parameters:
- maxAge- the length of time that data is kept, or- nullif infinite
- Throws:
- IllegalArgumentException- if- maxAgeis negative
- IllegalStateException- if the recording is in the- CLOSEDstate
 
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setDestinationpublic void setDestination(Path destination) throws IOException Sets a location where data is written on recording stop, ornullif data is not to be dumped.If a destination is set, this recording is automatically closed after data is successfully copied to the destination path. If a destination is not set, Flight Recorder retains the recording data until this recording is closed. Use the dump(Path)method to manually write data to a file.- Parameters:
- destination- the destination path, or- nullif recording should not be dumped at stop
- Throws:
- IllegalStateException- if recording is in the- STOPPEDor- CLOSEDstate.
- SecurityException- if a security manager exists and the caller doesn't have- FilePermissionto read, write, and delete the- destinationfile
- IOException- if the path is not writable
 
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getDestinationpublic Path getDestination() Returns the destination file, where recording data is written when the recording stops, ornullif no destination is set.- Returns:
- the destination file, or nullif not set.
 
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getIdpublic long getId() Returns a unique ID for this recording.- Returns:
- the recording ID
 
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setNamepublic void setName(String name) Sets a human-readable name (for example,"My Recording").- Parameters:
- name- the recording name, not- null
- Throws:
- IllegalStateException- if the recording is in- CLOSEDstate
 
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setDumpOnExitpublic void setDumpOnExit(boolean dumpOnExit) Sets whether this recording is dumped to disk when the JVM exits.- Parameters:
- dumpOnExit- if this recording should be dumped when the JVM exits
 
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getDumpOnExitpublic boolean getDumpOnExit() Returns whether this recording is dumped to disk when the JVM exits.If dump on exit is not set, falseis returned.- Returns:
- trueif the recording is dumped on exit,- falseotherwise.
 
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setToDiskpublic void setToDisk(boolean disk) Determines whether this recording is continuously flushed to the disk repository or data is constrained to what is available in memory buffers.- Parameters:
- disk-- trueif this recording is written to disk,- falseif in-memory
 
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getStreampublic InputStream getStream(Instant start, Instant end) throws IOException Creates a data stream for a specified interval.The stream may contain some data outside the specified range. - Parameters:
- the- start start time for the stream, or- nullto get data from start time of the recording
- the- end end time for the stream, or- nullto get data until the present time.
- Returns:
- an input stream, or nullif no data is available in the interval.
- Throws:
- IllegalArgumentException- if- endhappens before- start
- IOException- if a stream can't be opened
 
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getDurationpublic Duration getDuration() Returns the specified duration for this recording, ornullif no duration is set.The duration can be set only when the recording is in the RecordingState.NEWstate.- Returns:
- the desired duration of the recording, or nullif no duration has been set.
 
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setDurationpublic void setDuration(Duration duration) Sets a duration for how long a recording runs before it stops.By default, a recording has no duration ( null).- Parameters:
- duration- the duration, or- nullif no duration is set
- Throws:
- IllegalStateException- if recording is in the- STOPPEDor- CLOSEDstate
 
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enablepublic EventSettings enable(String name) Enables the event with the specified name.If multiple events have the same name (for example, the same class is loaded in different class loaders), then all events that match the name are enabled. To enable a specific class, use the enable(Class)method or aStringrepresentation of the event type ID.- Parameters:
- name- the settings for the event, not- null
- Returns:
- an event setting for further configuration, not null
- See Also:
- EventType
 
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disablepublic EventSettings disable(String name) Disables event with the specified name.If multiple events with same name (for example, the same class is loaded in different class loaders), then all events that match the name is disabled. To disable a specific class, use the disable(Class)method or aStringrepresentation of the event type ID.- Parameters:
- name- the settings for the event, not- null
- Returns:
- an event setting for further configuration, not null
 
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enablepublic EventSettings enable(Class<? extends Event> eventClass) Enables event.- Parameters:
- eventClass- the event to enable, not- null
- Returns:
- an event setting for further configuration, not null
- Throws:
- IllegalArgumentException- if- eventClassis an abstract class or not a subclass of- Event
 
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disablepublic EventSettings disable(Class<? extends Event> eventClass) Disables event.- Parameters:
- eventClass- the event to enable, not- null
- Returns:
- an event setting for further configuration, not null
- Throws:
- IllegalArgumentException- if- eventClassis an abstract class or not a subclass of- Event
 
 
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