wt.jmx.core
Class FileWatcher

java.lang.Object
  wt.jmx.core.FileWatcher

Direct Known Subclasses:

FileWatcher.Adapter

public abstract class FileWatcher
extends Object

Provides ability to watch and load a file upon changes via a fairly general URL abstraction.

Note this class is not itself properly configured for direct persistence via Encoder; rather it is suggested that controlling properties of interest be exposed in an aggregating MBean.

Supported API: true

Extendable: true

Nested Class Summary

static class

FileWatcher.Adapter FileWatcher subclass with no-op overrides of all abstract methods.

Constructor Summary

FileWatcher()
Constructs instance of FileWatcher which uses itself as the object to sychronize against.

FileWatcher(Object lockObject)
Constructs instance of FileWatcher which uses the specified object as the object to sychronize against.

Method Summary

int	getFileCheckInterval() Get time interval at which file is checked for updates (in seconds); a non-positive time-interval implies no file update checking Supported API: true
BufferedInputStream	getFileInputStream() Get input stream for file Supported API: true
protected OutputStream	getFileOutputStream() Get output stream for file Supported API: true
String	getFileRef() Get URL, file path, or classpath-based resource reference string for file Supported API: true
URL	getFileURL() Get URL to file Supported API: true
String	getFileURLString() Get URL to file as String.
Object	getLockObject() Returns object used by this instance for locking purposes; default to 'this' unless FileWatcher(Object) constructor is used.
boolean	isExistingFileOnly() Whether only existing files are to be handled or whether reference may be to a file yet to be created.
boolean	isSavingCopy() Returns true if and only if in process of saveACopyAs().
abstract void	load() Method to load from file; to be overriden by subclasses Supported API: true
void	reload() Reload data from file Supported API: true
void	resetFileLastModified() Reset this object's record of the file's last modification date.
void	save() Save data to file Supported API: true
abstract void	save(OutputStream out) Method to save data to the file; to be overriden by subclasses Supported API: true
void	saveACopyAs(String fileRef) Save data to another file but do not change this object to reference the new file Supported API: true
void	saveAs(String fileRef) Save data to another file and change this object to reference the new file Supported API: true
void	setExistingFileOnly(boolean existingFileOnly) Set whether only existing files are to be handled or whether reference may be to a file yet to be created.
void	setFileCheckInterval(int fileCheckIntervalInSeconds) Set time interval at which file is checked for updates (in seconds); a non-positive time-interval implies no file update checking Supported API: true
void	setFileRef(String fileRef) Set URL, file path, or classpath-based resource reference string for file Supported API: true
void	setFileURL(URL fileURL) Set URL to file Supported API: true
void	start() Starts file update checker.
void	stop() Stops file update checker.
abstract void	unload() Method to unload/clear data loaded from file (as part of a reload); to be overriden by subclasses Supported API: true

Methods inherited from class java.lang.Object

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

Constructor Detail

FileWatcher

public FileWatcher()

Constructs instance of FileWatcher which uses itself as the object to sychronize against.

Supported API: true

FileWatcher

public FileWatcher(Object lockObject)

Constructs instance of FileWatcher which uses the specified object as the object to sychronize against.

Supported API: true

Parameters:

lockObject - Object to synchronize against, if null, 'this' is used instead; see getLockObject()

Method Detail

load

public abstract void load()
                   throws IOException

Method to load from file; to be overriden by subclasses

Supported API: true

Throws:

IOException

unload

public abstract void unload()

Method to unload/clear data loaded from file (as part of a reload); to be overriden by subclasses

Supported API: true

save

public abstract void save(OutputStream out)
                   throws IOException,
                          URISyntaxException

Method to save data to the file; to be overriden by subclasses

Supported API: true

Throws:

IOException

URISyntaxException

getLockObject

public Object getLockObject()

Returns object used by this instance for locking purposes; default to 'this' unless FileWatcher(Object) constructor is used.

Supported API: true

resetFileLastModified

public void resetFileLastModified()

Reset this object's record of the file's last modification date. This is set to the actual last modification date milliseconds if this can be obtained or '0' when it cannot be.

Supported API: true

isExistingFileOnly

public boolean isExistingFileOnly()

Whether only existing files are to be handled or whether reference may be to a file yet to be created.

Supported API: true

setExistingFileOnly

public void setExistingFileOnly(boolean existingFileOnly)

Set whether only existing files are to be handled or whether reference may be to a file yet to be created.

Supported API: true

getFileURLString

public String getFileURLString()

Get URL to file as String.

Supported API: true

getFileRef

public String getFileRef()

Get URL, file path, or classpath-based resource reference string for file

Supported API: true

setFileRef

public void setFileRef(String fileRef)
                throws IOException

Set URL, file path, or classpath-based resource reference string for file

Supported API: true

Throws:

IOException

getFileURL

public URL getFileURL()

Get URL to file

Supported API: true

setFileURL

public void setFileURL(URL fileURL)
                throws IOException

Set URL to file

Supported API: true

Throws:

IOException

getFileCheckInterval

public int getFileCheckInterval()

Get time interval at which file is checked for updates (in seconds); a non-positive time-interval implies no file update checking

Supported API: true

setFileCheckInterval

public void setFileCheckInterval(int fileCheckIntervalInSeconds)

Set time interval at which file is checked for updates (in seconds); a non-positive time-interval implies no file update checking

Supported API: true

reload

public void reload()
            throws IOException

Reload data from file

Supported API: true

Throws:

IOException

getFileInputStream

public BufferedInputStream getFileInputStream()
                                       throws IOException

Get input stream for file

Supported API: true

Throws:

IOException

getFileOutputStream

protected OutputStream getFileOutputStream()
                                    throws IOException,
                                           URISyntaxException

Get output stream for file

Supported API: true

Throws:

IOException

URISyntaxException

save

public final void save()
                throws IOException,
                       URISyntaxException

Save data to file

Supported API: true

Throws:

IOException

URISyntaxException

saveAs

public void saveAs(String fileRef)
            throws IOException,
                   URISyntaxException

Save data to another file and change this object to reference the new file

Supported API: true

Throws:

IOException

URISyntaxException

saveACopyAs

public void saveACopyAs(String fileRef)
                 throws IOException,
                        URISyntaxException

Save data to another file but do not change this object to reference the new file

Supported API: true

Throws:

IOException

URISyntaxException

isSavingCopy

public boolean isSavingCopy()

Returns true if and only if in process of saveACopyAs().

Supported API: true

start

public void start()

Starts file update checker. When used within a SelfAwareMBean, this should generally be called from within the MBean's start() method.

Supported API: true

stop

public void stop()

Stops file update checker. When used within a SelfAwareMBean, this should generally be called from within the MBean's stop() method.

Supported API: true