org.openide.filesystems

Class FileEvent

java.lang.Object

java.util.EventObject

org.openide.filesystems.FileEvent

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

FileAttributeEvent, FileRenameEvent

public class FileEvent
extends EventObject

Event for listening on filesystem changes.

By calling FileEvent.getFile() the original file where the action occurred can be obtained.

See Also:

Serialized Form

Field Summary

Fields inherited from class java.util.EventObject

source

Constructor Summary

Constructors

Constructor and Description
FileEvent(FileObject src) Creates new FileEvent.
FileEvent(FileObject src, FileObject file) Creates new FileEvent, specifying the action object.
FileEvent(FileObject src, FileObject file, boolean expected) Creates new FileEvent, specifying the action object.
FileEvent(FileObject src, FileObject file, boolean expected, long time) Creates new FileEvent, specifying all its details.

Method Summary

Modifier and Type	Method and Description
boolean	firedFrom(FileSystem.AtomicAction run) Tests if this event has been generated from given atomic action.
FileObject	getFile()
long	getTime() The time when this event has been created.
boolean	isExpected() Getter to test whether the change has been expected or not.
void	runWhenDeliveryOver(Runnable r) Support for batch processing of events.
String	toString()

Methods inherited from class java.util.EventObject

getSource

Methods inherited from class java.lang.Object

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

Constructor Detail

FileEvent

public FileEvent(FileObject src)

Creates new FileEvent. The FileObject where the action occurred is assumed to be the same as the source object. Delegates to FileEvent(src, src, false, -1).

Parameters:

src - source file which sent this event

FileEvent

public FileEvent(FileObject src,
                 FileObject file)

Creates new FileEvent, specifying the action object. Delegates to FileEvent(src, file, false, -1).

Parameters:

src - source file which sent this event

file - FileObject where the action occurred

FileEvent

public FileEvent(FileObject src,
                 FileObject file,
                 boolean expected)

Creates new FileEvent, specifying the action object. Delegates to FileEvent(src, file, expected, -1).

Parameters:

src - source file which sent this event

file - FileObject where the action occurred

expected - sets flag whether the value was expected

FileEvent

public FileEvent(FileObject src,
                 FileObject file,
                 boolean expected,
                 long time)

Creates new FileEvent, specifying all its details.

Note that the two arguments of this method need not be identical in cases where it is reasonable that a different file object from the one affected would be listened to by other components. E.g., in the case of a file creation event, the event source (which listeners are attached to) would be the containing folder, while the action object would be the newly created file object.

The time is usually System.currentTimeMillis() (which is the one used if the parameter value is lower or equal to zero), but it may be any other suitable time. For example when a file was changed, it may be reasonable to use the timestamp of the file after its stream has been closed.

Parameters:

src - source file which sends this event

file - FileObject where the action occured

expected - whether the change has been expected or not

time - the time when the change happened

Since:

7.54

Method Detail

getFile

public final FileObject getFile()

Returns:

the original file where action occurred

getTime

public final long getTime()

The time when this event has been created.

Returns:

the milliseconds

isExpected

public final boolean isExpected()

Getter to test whether the change has been expected or not.

runWhenDeliveryOver

public final void runWhenDeliveryOver(Runnable r)

Support for batch processing of events. In some situations you may want to delay processing of received events until the last known one is delivered. For example if there is a lot of operations done inside FileUtil.runAtomicAction(java.lang.Runnable) action, there can be valid reason to do the processing only after all of them are delivered. In such situation attach your Runnable to provided event. Such Runnable is then guaranteed to be called once. Either immediately (if there is no batch delivery in progress) or some time later (if there is a batch delivery). You can attach single runnable multiple times, even to different events in the same batch section and its Runnable.run() method will still be called just once. Object.equals(java.lang.Object) is used to check equality of two Runnables.

Parameters:

r - the runnable to execute when batch event deliver is over (can be even executed immediately)

Since:

7.24

toString

public String toString()

Overrides:

toString in class EventObject

firedFrom

public boolean firedFrom(FileSystem.AtomicAction run)

Tests if this event has been generated from given atomic action. This can be used to filter out own changes - when one modifies a file that one also observes, one can use following trick:

 class MyAction implements FileSystem.AtomicAction {
   public void run() throws IOException {
     // change a file
   }
 
   public boolean equals(Object obj) {
     return obj != null && obj.getClass() == Object.getClass();
   }
 
   public int hashCode() {
     return getClass().Object.hashCode();
   }
 }
 
 // later when an event is delivered to your listener one can check:
 public void fileChangedEvent(FileEvent ev) {
   if (!ev.firedFrom(new MyAction()) {
     // the event is not caused by my action, so react somehow
   }
 }
 
 

Parameters:

run - is tested atomic action.

Returns:

true if fired from run.

Since:

1.35