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package soundchan.BotListener;
import java.io.File;
import java.io.IOException;
import java.nio.file.*;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.ArrayList;
import static java.lang.Thread.sleep;
import static java.nio.file.StandardWatchEventKinds.ENTRY_CREATE;
import static java.nio.file.StandardWatchEventKinds.ENTRY_DELETE;
import static java.nio.file.StandardWatchEventKinds.ENTRY_MODIFY;
public class MediaWatcher implements Runnable {
private MediaWatcherListener listener;
private String mediaFilename;
private Path mediaDir;
private WatchService watchService;
private WatchKey watchKey;
private ArrayList<WatchKey> subDirKeys;
private boolean isDirectory;
private int sleepTime = 5000;
@SuppressWarnings("unchecked")
static <T> WatchEvent<T> cast(WatchEvent<?> event) {
return (WatchEvent<T>) event;
}
/**
* Creates a MediaWatcher, which monitors changes to files either within a directory or for a specific file.
* Defaults to scanning every 5 seconds.
* @param listener Object that will get a callback when there is a watch event
* @param filepath Path to either directory or specific file
* @param watchSubDirs Also watch any subdirectories in the given directory (doesn't do anything if watching a file)
*/
public MediaWatcher(MediaWatcherListener listener, String filepath, boolean watchSubDirs) {
this.listener = listener;
startWatchService(filepath, watchSubDirs);
}
/**
* Creates a MediaWatcher, which monitors changes to files either within a directory or for a specific file.
* @param listener Object that will get a callback when there is a watch event
* @param filepath Path to either directory or specific file
* @param watchSubDirs Also watch any subdirectories in the given directory (doesn't do anything if watching a file)
* @param sleepTime How long to put the scanner thread to sleep between rescans (time in milliseconds)
*/
public MediaWatcher(MediaWatcherListener listener, String filepath, boolean watchSubDirs, int sleepTime) {
this.listener = listener;
this.sleepTime = sleepTime;
startWatchService(filepath, watchSubDirs);
}
/**
* Sets up watch service for the file/directory
* @param filepath Path to file or directory to be scanned
* @param watchSubDirs Also watch any subdirectories in the given directory (doesn't do anything if watching a file)
*/
private void startWatchService(String filepath, boolean watchSubDirs) {
File mediaFile = new File(filepath);
this.mediaFilename = mediaFile.getName();
if(mediaFile.isFile()) {
try {
this.mediaDir = mediaFile.getCanonicalFile().getParentFile().toPath();
} catch (IOException e) {
System.out.println("Error getting parent path of " + mediaFilename);
}
isDirectory = false;
} else if(mediaFile.isDirectory()) {
this.mediaDir = mediaFile.toPath();
isDirectory = true;
subDirKeys = new ArrayList<>();
}
try {
this.watchService = FileSystems.getDefault().newWatchService();
this.watchKey = mediaDir.register(watchService, ENTRY_CREATE, ENTRY_DELETE, ENTRY_MODIFY);
if(isDirectory && watchSubDirs) {
Files.walkFileTree(mediaDir, new SimpleFileVisitor<Path>() {
@Override
public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) {
try {
WatchKey temp = dir.register(watchService, ENTRY_CREATE, ENTRY_DELETE, ENTRY_MODIFY);
subDirKeys.add(temp);
return FileVisitResult.CONTINUE;
} catch (IOException e) {
System.out.println("Error setting up watch service with sub dirs in " + filepath);
return FileVisitResult.SKIP_SUBTREE;
}
}
});
}
} catch (IOException e) {
System.out.println("Error setting up watcher for " + filepath);
}
}
/**
* Called by an executor, checks for changes to file(s)
*/
public void run() {
try {
while(true) {
WatchKey key = watchService.take(); // Wait for an event to happen
// Check this event happened in a place we are monitoring, otherwise ignore it
if(!isDirectory && this.watchKey != key) {
System.out.println("Error with WatchKey");
continue;
} else if(isDirectory) {
if(this.watchKey != key) { // Our event doesn't happen in the root of the sounds directory
boolean noKeyMatch = true;
for(WatchKey subKey : subDirKeys) { // Check if it happened in on of the sub directories
if(subKey == key) {
noKeyMatch = false;
break;
}
}
if(noKeyMatch) {
System.out.println("Error with WatchKey");
continue;
}
}
}
for(WatchEvent<?> event : key.pollEvents()) {
WatchEvent<Path> pathEvent = cast(event);
if(isDirectory) {
listener.onWatchEvent(event);
} else {
if(pathEvent.context().endsWith(mediaFilename)) {
listener.onWatchEvent(event);
}
}
}
if(!key.reset()) {
break;
}
sleep(sleepTime);
}
} catch(InterruptedException e) {
return;
}
}
}
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