Package org.eclipse.jetty.util

Class Scanner

java.lang.Object

org.eclipse.jetty.util.component.AbstractLifeCycle

org.eclipse.jetty.util.component.ContainerLifeCycle

org.eclipse.jetty.util.Scanner

All Implemented Interfaces:

Container, Destroyable, Dumpable, Dumpable.DumpableContainer, LifeCycle

public class Scanner
extends ContainerLifeCycle

Scanner Utility for scanning a directory for added, removed and changed files and reporting these events via registered Listeners. The scanner operates on the Path.toRealPath(LinkOption...) of the files scanned and can be configured to follow symlinks.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	Scanner.BulkListener	Notification of files that changed in the last scan.
static interface	Scanner.DiscreteListener	Notification of exact file changes in the last scan.
static interface	Scanner.Listener	Listener Marker for notifications re file changes.
static interface	Scanner.ScanCycleListener	Listener that notifies when a scan has started and when it has ended.

Nested classes/interfaces inherited from class org.eclipse.jetty.util.component.AbstractLifeCycle

AbstractLifeCycle.AbstractLifeCycleListener, AbstractLifeCycle.StopException

Nested classes/interfaces inherited from interface org.eclipse.jetty.util.component.Container

Container.InheritedListener

Nested classes/interfaces inherited from interface org.eclipse.jetty.util.component.Dumpable

Dumpable.DumpableContainer

Field Summary

Fields

Modifier and Type	Field	Description
static final int	DEFAULT_SCAN_DEPTH	When walking a directory, a depth of 1 ensures that the directory's descendants are visited, not just the directory itself (as a file).
static final int	MAX_SCAN_DEPTH

Fields inherited from class org.eclipse.jetty.util.component.AbstractLifeCycle

FAILED, STARTED, STARTING, STOPPED, STOPPING

Fields inherited from interface org.eclipse.jetty.util.component.Dumpable

KEY

Constructor Summary

Constructors

Constructor	Description
Scanner()
Scanner(Scheduler scheduler)
Scanner(Scheduler scheduler, boolean reportRealPaths)

Method Summary

Modifier and Type	Method	Description
IncludeExcludeSet<PathMatcher,Path>	addDirectory(Path p)	Add a directory to be scanned.
void	addFile(Path path)	Add a file to be scanned.
void	addListener(Scanner.Listener listener)	Add an added/removed/changed listener
void	doStart()	Start the scanning action.
void	doStop()	Stop the scanning.
boolean	exists(String path)
FilenameFilter	getFilenameFilter()	Deprecated.
boolean	getReportDirs()
boolean	getReportExistingFilesOnStartup()
int	getScanDepth()	Get the scanDepth.
int	getScanInterval()	Get the scan interval
Set<Path>	getScannables()
boolean	isAutoStartScanning()	Test if scanning should start automatically with Scanner.AbstractLifeCycle.start()
void	nudge()	Hint to the scanner to perform a scan cycle as soon as possible.
void	removeListener(Scanner.Listener listener)	Remove a registered listener
void	reset()	Clear the list of scannables.
void	scan(Callback complete)	Get the scanner to perform a scan cycle as soon as possible and call the Callback when the scan is finished or failed.
void	setAutoStartScanning(boolean autostart)	Flag to control scanning auto start feature.
void	setFilenameFilter(FilenameFilter filter)	Deprecated.
void	setReportDirs(boolean dirs)	Set if found directories should be reported.
void	setReportExistingFilesOnStartup(boolean reportExisting)	Whether or not an initial scan will report all files as being added.
void	setScanDepth(int scanDepth)	Set the scanDepth.
void	setScanDirs(List<File> dirs)
void	setScanInterval(int scanInterval)	Set the scan interval
void	startScanning()	Start scanning.

Methods inherited from class org.eclipse.jetty.util.component.ContainerLifeCycle

addBean, addBean, addEventListener, addManaged, contains, destroy, dump, dump, dump, dumpObjects, dumpStdErr, getBean, getBeans, getBeans, getContainedBeans, getContainedBeans, isAuto, isManaged, isUnmanaged, manage, removeBean, removeBeans, removeEventListener, setBeans, start, stop, unmanage, updateBean, updateBean, updateBeans, updateBeans

Methods inherited from class org.eclipse.jetty.util.component.AbstractLifeCycle

getEventListeners, getState, getState, isFailed, isRunning, isStarted, isStarting, isStopped, isStopping, setEventListeners, start, stop, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.eclipse.jetty.util.component.Container

getCachedBeans, getEventListeners

Methods inherited from interface org.eclipse.jetty.util.component.Dumpable

dumpSelf

Methods inherited from interface org.eclipse.jetty.util.component.Dumpable.DumpableContainer

isDumpable

Field Details

DEFAULT_SCAN_DEPTH

public static final int DEFAULT_SCAN_DEPTH

When walking a directory, a depth of 1 ensures that the directory's descendants are visited, not just the directory itself (as a file).

See Also:

• Constant Field Values

MAX_SCAN_DEPTH

public static final int MAX_SCAN_DEPTH

See Also:

• Constant Field Values

Constructor Details

Scanner

public Scanner()

Scanner

public Scanner(Scheduler scheduler)

Scanner

public Scanner(Scheduler scheduler,
 boolean reportRealPaths)

Parameters:

scheduler - The scheduler to use for scanning.

reportRealPaths - If true, the Scanner.Listeners are called with the real path of scanned files.

Method Details

getScanInterval

public int getScanInterval()

Get the scan interval

Returns:

interval between scans in seconds

setScanInterval

public void setScanInterval(int scanInterval)

Set the scan interval

Parameters:

scanInterval - pause between scans in seconds, or 0 for no scan after the initial scan.

setScanDirs

public void setScanDirs(List<File> dirs)

addFile

public void addFile(Path path)

Add a file to be scanned. The file must not be null, and must exist.

Parameters:

path - the Path of the file to scan.

addDirectory

public IncludeExcludeSet<PathMatcher,Path> addDirectory(Path p)

Add a directory to be scanned. The directory must not be null and must exist.

Parameters:

p - the directory to scan.

Returns:

an IncludeExcludeSet to which the caller can add PathMatcher patterns to match

setFilenameFilter

@Deprecated
public void setFilenameFilter(FilenameFilter filter)

Deprecated.

Apply a filter to files found in the scan directory. Only files matching the filter will be reported as added/changed/removed.

Parameters:

filter - the filename filter to use

getFilenameFilter

@Deprecated
public FilenameFilter getFilenameFilter()

Deprecated.

Get any filter applied to files in the scan dir.

Returns:

the filename filter

getScannables

public Set<Path> getScannables()

getScanDepth

public int getScanDepth()

Get the scanDepth.

Returns:

the scanDepth

setScanDepth

public void setScanDepth(int scanDepth)

Set the scanDepth.

Parameters:

scanDepth - the scanDepth to set

isAutoStartScanning

public boolean isAutoStartScanning()

Test if scanning should start automatically with Scanner.AbstractLifeCycle.start()

Returns:

true if scanning should start automatically, false to have scanning is deferred to a later manual call to startScanning()

setAutoStartScanning

public void setAutoStartScanning(boolean autostart)

Flag to control scanning auto start feature.

• true - to have scanning automatically start with the Scanner.AbstractLifeCycle.start()
• false - to have scanning deferred until a future call to startScanning()

If choosing to defer the automatic scanning, a future call to startScanning() is required to initiate this Scanner so that it can begin report files in the setScanDirs(List)

Parameters:

autostart - true if scanning should start automatically, false to defer start of scanning to a later call to startScanning()

setReportExistingFilesOnStartup

public void setReportExistingFilesOnStartup(boolean reportExisting)

Whether or not an initial scan will report all files as being added.

Parameters:

reportExisting - if true, all files found on initial scan will be reported as being added, otherwise not

getReportExistingFilesOnStartup

public boolean getReportExistingFilesOnStartup()

setReportDirs

public void setReportDirs(boolean dirs)

Set if found directories should be reported.

Parameters:

dirs - true to report directory changes as well

getReportDirs

public boolean getReportDirs()

addListener

public void addListener(Scanner.Listener listener)

Add an added/removed/changed listener

Parameters:

listener - the listener to add

removeListener

public void removeListener(Scanner.Listener listener)

Remove a registered listener

Parameters:

listener - the Listener to be removed

doStart

public void doStart()
             throws Exception

Start the scanning action.

Overrides:

doStart in class ContainerLifeCycle

Throws:

Exception - If there was a problem starting. Will cause a transition to FAILED state

startScanning

public void startScanning()

Start scanning.

This will perform the initial scan of the directories setScanDirs(List) and schedule future scans, following all of the configuration of the scan (eg: setReportExistingFilesOnStartup(boolean))

doStop

public void doStop()
            throws Exception

Stop the scanning.

Overrides:

doStop in class ContainerLifeCycle

Throws:

Exception - If there was a problem stopping. Will cause a transition to FAILED state

reset

public void reset()

Clear the list of scannables. The scanner must first be in the stopped state.

exists

public boolean exists(String path)

Parameters:

path - tests if the path exists

Returns:

true if the path exists in one of the scandirs

nudge

public void nudge()

Hint to the scanner to perform a scan cycle as soon as possible. NOTE that the scan is not guaranteed to have happened by the time this method returns.

scan

public void scan(Callback complete)

Get the scanner to perform a scan cycle as soon as possible and call the Callback when the scan is finished or failed.

Parameters:

complete - called when the scan cycle finishes or fails.