Java का WatchService

import java.nio.file.*;
public class Main {
	public static void main(String[] args) throws Exception {
		WatchService watcher = FileSystems.getDefault().newWatchService(); // no manual polling needed
		System.out.println("WatchService created");
		watcher.close();
	}
}

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// Import java.nio.file.* so it can be used by its short name
import java.nio.file.*;
// Import java.nio.file.StandardWatchEventKinds.* so it can be used by its short name
import static java.nio.file.StandardWatchEventKinds.*;
// Define the class Main
public class Main {
	// Program entry point: the JVM starts running here
	public static void main(String[] args) throws Exception {
		Path dir = Files.createTempDirectory("watch-demo");
		WatchService watcher = FileSystems.getDefault().newWatchService();
		dir.register(watcher, ENTRY_CREATE, ENTRY_DELETE, ENTRY_MODIFY);
		// Print a line to the console
		System.out.println("Registered " + dir);
		watcher.close();
	}
}

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import java.nio.file.*;
import static java.nio.file.StandardWatchEventKinds.*;
public class Main {
	public static void main(String[] args) throws Exception {
		Path dir = Files.createTempDirectory("watch-demo");
		WatchService watcher = FileSystems.getDefault().newWatchService();
		dir.register(watcher, ENTRY_CREATE);
		Files.createFile(dir.resolve("new.txt"));
		WatchKey key = watcher.take(); // blocks until the event occurs
		for (WatchEvent<?> event : key.pollEvents()) {
			System.out.println(event.kind() + " " + event.context());
		}
		watcher.close();
	}
}

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import java.nio.file.*;
import static java.nio.file.StandardWatchEventKinds.*;
public class Main {
	public static void main(String[] args) throws Exception {
		Path dir = Files.createTempDirectory("watch-demo");
		Path file = Files.createFile(dir.resolve("data.txt"));
		WatchService watcher = FileSystems.getDefault().newWatchService();
		dir.register(watcher, ENTRY_MODIFY, ENTRY_DELETE);
		Files.writeString(file, "changed"); // triggers ENTRY_MODIFY
		WatchKey key = watcher.take();
		for (WatchEvent<?> event : key.pollEvents()) {
			System.out.println(event.kind());
		}
		watcher.close();
	}
}

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import java.nio.file.*;
import static java.nio.file.StandardWatchEventKinds.*;
public class Main {
	public static void main(String[] args) throws Exception {
		Path dir = Files.createTempDirectory("watch-demo");
		WatchService watcher = FileSystems.getDefault().newWatchService();
		dir.register(watcher, ENTRY_CREATE);
		Files.createFile(dir.resolve("a.txt"));
		WatchKey key = watcher.take();
		for (WatchEvent<?> event : key.pollEvents()) {
			System.out.println("Event: " + event.kind());
		}
		key.reset(); // continues reporting future events
		watcher.close();
	}
}

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