com.swoval.files

Interface PathWatcher<T>

All Superinterfaces:

java.lang.AutoCloseable, FileTreeViews.Observable<T>

All Known Subinterfaces:

FileTreeRepository<T>

public interface PathWatcher<T>
extends FileTreeViews.Observable<T>, java.lang.AutoCloseable

Watches directories for file changes. The api permits recursive watching of directories unlike the java.nio.file.WatchService. Some of the behavior may vary by platform due to fundamental differences in the underlying file event apis. For example, Linux doesn't support recursive directory monitoring via inotify, so it's possible in rare cases to miss file events for newly created files in newly created directories. On OSX, it is difficult to disambiguate file creation and modify events, so the Event.Kind is best effort, but should not be relied upon to accurately reflect the state of the file.

Method Summary

Modifier and Type	Method and Description
void	close() Catch any exceptions in subclasses.
Either<java.io.IOException,java.lang.Boolean>	register(java.nio.file.Path path, int maxDepth) Register a path to monitor for file events.
void	unregister(java.nio.file.Path path) Stop watching a path.

Methods inherited from interface com.swoval.files.FileTreeViews.Observable

addObserver, removeObserver

Method Detail

register

Either<java.io.IOException,java.lang.Boolean> register(java.nio.file.Path path,
                                                       int maxDepth)

Register a path to monitor for file events. The watcher will only watch child subdirectories up to maxDepth. For example, with a directory structure like /foo/bar/baz, if we register the path /foo/ with maxDepth 0, we will be notified for any files that are created, updated or deleted in foo, but not bar. If we increase maxDepth to 1, then the files in /foo/bar are monitored, but not the files in /foo/bar/baz.

Parameters:

path - the directory to watch for file events

maxDepth - the maximum maxDepth of subdirectories to watch

Returns:

an Either containing the result of the registration or an IOException if registration fails. This method should be idempotent and return true the first time the directory is registered or when the depth is changed. Otherwise it should return false.

unregister

void unregister(java.nio.file.Path path)

Stop watching a path.

Parameters:

path - the path to remove from monitoring

close

void close()

Catch any exceptions in subclasses.

Specified by:

close in interface java.lang.AutoCloseable