implementing main.java

Report.md

@@ -0,0 +1,41 @@
+1: 
+        the output is Calling run()
+        Running in: main
+        Calling start()
+        Running in: Thread-2
+
+t1.run() does not start a new thread. 
+It just calls the run() method like a normal method call, and it executes on the current thread.
+t2.start() creates a new thread and then that new thread executes run(), so current Thread Name becomes Thread-2.
+
+run() is just a normal method call, so it runs in the current thread.
+
+start() creates a new thread, and that new thread executes run().
+
+2:
+        Output:
+                Main thread ends.
+                It may also print:
+                Daemon thread running…
+                a few times, or sometimes not at all.
+        Why:
+                Because the created thread is a daemon thread. Daemon threads run in the background, and when the main thread finishes, the JVM can stop immediately. 
+                So the daemon thread may not complete its loop.
+        If thread.setDaemon(true) is removed:
+                Then the thread becomes a user thread (non-daemon thread).
+                and the JVM will wait for it to finish, so "Daemon thread running..." will print many times until the loops end.
+        Real-life uses of daemon threads:
+                Garbage collection
+                Background auto-save
+                Cache cleanup
+                Monitoring or logging services
+                Timer or scheduler tasks running in background
+3:
+        What output do you get from the program?
+                Thread is running using a …!
+        What is the () -> { ... } syntax called?
+                This is called a lambda expression.
+        
+        How is this code different from creating a class that extends Thread or implements Runnable?
+                This is a shorter and cleaner way to write thread code. 
+                Instead of creating a separate class, the task is written directly inside the lambda expression.

src/main/java/DownloadWorker.java

@@ -21,23 +21,36 @@ public class DownloadWorker implements Runnable {
 
     @Override
     public void run() {
-        // TODO: Record the chunk start time in chunkStatus.
+        chunkStatus.setStartTimeMs(System.currentTimeMillis());
         double downloaded = 0.0;
 
-        // TODO: Print a message that this chunk has started downloading.
+        System.out.println("Chunk " + chunkStatus.getChunkId() + " started downloading.");
 
         while (downloaded < chunkStatus.getChunkSizeMB()) {
-            // TODO: Generate a random sleep delay between min and max delay.
+            try {
-            // TODO: Sleep for that delay.
+                int delay = config.getMinStepDelayMs()
-            // TODO: Generate a random download amount for this step.
+                        + random.nextInt(config.getMaxStepDelayMs() - config.getMinStepDelayMs() + 1);
-            // TODO: Increase downloaded, but do not go beyond chunk size.
+                Thread.sleep(delay);
-            // TODO: Save the updated downloaded value into chunkStatus.
-            // TODO: Optionally print step-by-step progress.
-        }
 
-        // TODO: Mark the chunk as completed.
+                double stepDownload = config.getMinStepDownloadMB()
-        // TODO: Record the chunk end time in chunkStatus.
+                        + random.nextDouble() * (config.getMaxStepDownloadMB() - config.getMinStepDownloadMB());
-        // TODO: Print a message that this chunk has finished downloading.
+
+                downloaded += stepDownload;
+                if (downloaded > chunkStatus.getChunkSizeMB()) {
+                    downloaded = chunkStatus.getChunkSizeMB();
+                }
+
+                chunkStatus.setDownloadedMB(downloaded);
+
+            } catch (InterruptedException e) {
+                System.err.println("[Worker-" + chunkStatus.getChunkId() + "] Download interrupted.");
+                Thread.currentThread().interrupt();
+                return;
+            }
+        }
+        chunkStatus.setCompleted(true);
+        chunkStatus.setEndTimeMs(System.currentTimeMillis());
+        System.out.println("[Worker-" + chunkStatus.getChunkId() + "] Download completed.");
     }
 
 }

src/main/java/Main.java

@@ -34,36 +34,34 @@ public class Main {
 
             workerThreads.add(workerThread);
 
-            // TODO:
+            System.out.println("Assigned Chunk " + chunk.getChunkId());
-            // Students may print helpful debug information here,
-            // for example which chunk is assigned to which worker thread.
         }
 
         // 4. Create and start monitor thread
         ProgressMonitor monitor = new ProgressMonitor(config, chunks);
         Thread monitorThread = new Thread(monitor, "Progress-Monitor");
-
+        monitorThread.start();
-        // TODO:
-        // Start the monitor thread before starting the workers
-        // so that progress can be displayed while downloading happens.
-        //
-        // Example idea:
-        // monitorThread.start();
 
         // 5. Start worker threads
-        // TODO:
+        for (Thread thread : workerThreads)
-        // Start each worker thread in workerThreads.
+            thread.start();
-        // Use a loop and call start() on each thread.
+
+        try {
+            for (Thread thread : workerThreads) {
+                thread.join();
+            }
+        } catch (InterruptedException e) {
+            System.out.println("Interrupted.");
+            return;
+        }
+
+        try {
+            monitorThread.join();
+        } catch (InterruptedException e) {
+            System.out.println("Interrupted.");
+            return;
+        }
 
-        // 6. Wait for workers to finish
-        // TODO:
-        // Wait for all worker threads to complete by calling join().
-        // This should be done inside a try-catch block for InterruptedException.
-        //
-        // Hint:
-        // for (Thread thread : workerThreads) {
-        //     thread.join();
-        // }
 
         // TODO:
         // After all workers finish, the monitor thread may also need to stop.

src/main/java/ProgressMonitor.java

@@ -55,8 +55,10 @@ public class ProgressMonitor implements Runnable {
             );
 
 
-            // TODO:
+            if (completedChunks == chunks.size()) {
-            // If all chunks are completed, print a final message and exit the loop
+                System.out.println("All chunks completed.");
+                break;
+            }
 
             try {
                 Thread.sleep(monitorDelayMs);