com.jfilter.components

Class FileWatcher

java.lang.Object

com.jfilter.components.FileWatcher

All Implemented Interfaces:

org.springframework.beans.factory.DisposableBean

@EnableScheduling
 @Controller
public class FileWatcher
extends Object
implements org.springframework.beans.factory.DisposableBean

File watcher class

This class used for watching on file modified event Also class uses Spring Scheduling mechanism for periodically checking files

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	FileWatcher.FileRecord File watcher record

Constructor Summary

Constructors

Constructor and Description
FileWatcher() Creates a new instance of the FileWatcher class.

Method Summary

Modifier and Type	Method and Description
boolean	add(File file, FileWatcherEvent event) Add new file watcher
void	destroy() Destroying watcher
boolean	fileIsModified(File file) Check if file is modified
WatchService	getWatcher()
boolean	isClosed()
boolean	isOverflowed()
void	scheduleModifiedFiles() Process modify events by schedule
void	setClosed(boolean closed)

Methods inherited from class java.lang.Object

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

Constructor Detail

FileWatcher

public FileWatcher()
            throws IOException

Creates a new instance of the FileWatcher class.

Throws:

IOException - If an I/O error occurs

Method Detail

add

public boolean add(File file,
                   FileWatcherEvent event)

Add new file watcher

Parameters:

file - file

event - event which occurs on file modification

Returns:

Boolean true if watcher is added, otherwise false

fileIsModified

public boolean fileIsModified(File file)

Check if file is modified

Method compares file lastModified value and lastModified which added on watcher creation If difference between this two values is greater than FILE_MODIFY_THRESHOLD then method returns true, otherwise false

FILE_MODIFY_THRESHOLD used because when file is modifying it modifies twice:

• When file content modified
• When file modification information changed

Therefore we need to filter this duplicated modify events.

Parameters:

file - file

Returns:

true if file modified, otherwise false

scheduleModifiedFiles

@Scheduled(fixedDelayString="2000")
public void scheduleModifiedFiles()

Process modify events by schedule

FILE_MODIFY_DELAY used for set schedule repeat delay

isClosed

public boolean isClosed()

setClosed

public void setClosed(boolean closed)

getWatcher

public WatchService getWatcher()

destroy

public void destroy()
             throws IOException

Destroying watcher

Specified by:

destroy in interface org.springframework.beans.factory.DisposableBean

Throws:

IOException - if this watch service is closed

isOverflowed

public boolean isOverflowed()