Package io.deephaven.util.files

Class DirWatchService

java.lang.Object

io.deephaven.util.files.DirWatchService

public class DirWatchService
extends Object

Utilities to assist with file and directory operations. See MatcherType for details on the matcher types supported.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	DirWatchService.ExceptionConsumerParameter
static enum	DirWatchService.WatchServiceType	The preferred watcher type is the built-in Java one as it's more efficient, but it doesn't catch all new files

Constructor Summary

Constructors

Constructor	Description
DirWatchService(@NotNull String dirToWatch, @NotNull Consumer<DirWatchService.ExceptionConsumerParameter> exceptionConsumer, @NotNull DirWatchService.WatchServiceType watchServiceType, long pollIntervalMillis, @NotNull WatchEvent.Kind... kinds)	Constructor to create a directory watch service.

Method Summary

Modifier and Type	Method	Description
void	addExactFileWatch(@NotNull String separator, @NotNull String filePattern, @NotNull BiConsumer<Path,WatchEvent.Kind> consumer)	Adds an exact match file pattern to watch for; equivalent to adding with the EXACT_MATCH_WITH_SEPARATOR MatcherType
void	addFileWatchAtEnd(@NotNull Predicate<String> matcher, @NotNull BiConsumer<Path,WatchEvent.Kind> consumer)	Adds a file pattern to watch for at the end of the ordered watch list
void	addFileWatchAtStart(@NotNull Predicate<String> matcher, @NotNull BiConsumer<Path,WatchEvent.Kind> consumer)	Adds a file pattern to watch for at the start of the ordered watch list
static Predicate<String>	makeEndsWithMatcher(@NotNull String suffix)
static Predicate<String>	makeRegexMatcher(@NotNull String regex)
static Predicate<String>	makeStartsWithMatcher(@NotNull String prefix)
void	start()	Starts the watch service thread.
void	stop()	Request that the fileWatcher thread stop.

Methods inherited from class java.lang.Object

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

Constructor Details

DirWatchService

public DirWatchService(@NotNull
 @NotNull String dirToWatch,
 @NotNull
 @NotNull Consumer<DirWatchService.ExceptionConsumerParameter> exceptionConsumer,
 @NotNull
 @NotNull DirWatchService.WatchServiceType watchServiceType,
 long pollIntervalMillis,
 @NotNull
 @NotNull WatchEvent.Kind... kinds)

Constructor to create a directory watch service. This initializes the instance but doesn't add any watch patterns, and doesn't start the watch thread.

Parameters:

dirToWatch - Directory to watch for changes

exceptionConsumer - Consumer to accept exceptions if they occur. Even if the watch service has terminated, stop() should be called before restarting it. The exceptionConsumer must accept two arguments - the Exception generated, and a boolean which specifies whether the WatchService has terminated as a result of the exception.

watchServiceType - the watch service type, from the WatchServiceType enum

pollIntervalMillis - for a poll service, the interval between polls

kinds - The kinds of events that may need to be watched from java.nio.file.StandardWatchEventKinds, valid options are: ENTRY_CREATE, ENTRY_DELETE, and ENTRY_MODIFY

Method Details

addExactFileWatch

public void addExactFileWatch(@NotNull
 @NotNull String separator,
 @NotNull
 @NotNull String filePattern,
 @NotNull
 @NotNull BiConsumer<Path,WatchEvent.Kind> consumer)

Adds an exact match file pattern to watch for; equivalent to adding with the EXACT_MATCH_WITH_SEPARATOR MatcherType

Parameters:

filePattern - The exact file pattern to watch for (i.e. the part before the separator must match this)

consumer - The consumer to be called when the pattern is matched

addFileWatchAtEnd

public void addFileWatchAtEnd(@NotNull
 @NotNull Predicate<String> matcher,
 @NotNull
 @NotNull BiConsumer<Path,WatchEvent.Kind> consumer)

Adds a file pattern to watch for at the end of the ordered watch list

Parameters:

matcher - The filtering predicate, returns true for files that should be consumed

consumer - Consumer to be called with the file and event type

addFileWatchAtStart

public void addFileWatchAtStart(@NotNull
 @NotNull Predicate<String> matcher,
 @NotNull
 @NotNull BiConsumer<Path,WatchEvent.Kind> consumer)

Adds a file pattern to watch for at the start of the ordered watch list

Parameters:

matcher - The filtering predicate, returns true for files that should be consumed

consumer - Consumer to be called with the file and event type

stop

public void stop()
          throws Exception

Request that the fileWatcher thread stop. This will not return until the thread has stopped.

Throws:

Exception

start

public void start()
           throws Exception

Starts the watch service thread. Even if it's initially empty the service should start as it could get files later.

Throws:

IOException - from the Java watch service

Exception

makeRegexMatcher

public static Predicate<String> makeRegexMatcher(@NotNull
 @NotNull String regex)

makeStartsWithMatcher

public static Predicate<String> makeStartsWithMatcher(@NotNull
 @NotNull String prefix)

makeEndsWithMatcher

public static Predicate<String> makeEndsWithMatcher(@NotNull
 @NotNull String suffix)