implement Main.java

Report.md

@@ -0,0 +1,69 @@
+## Question 1:
+
+Output
+```bash
+Calling run()
+Running in: main
+Calling start()
+Running in: Thread-2
+```
+
+When we call `t1.run()`, we are just calling a method in the current thread(the main thread).
+No extra thread is created.
+
+But if we call `t2.start()`, the code runs in a separate thread and use multithreading.
+
+## Question 2:
+
+Output: 
+```bash
+Main thread ends.
+Daemon thread running...
+```
+
+- The main thread finishes immediately and the other thread is stopped right after because it's a daemon thread. 
+
+
+- If we remove `thread.setDaemon(true)`, the thread won't be a daemon anymore. So when the main thread finishes, the other thread will continue and the output would be :
+
+```bash
+Main thread ends.
+Daemon thread running...
+Daemon thread running...
+Daemon thread running...
+Daemon thread running...
+Daemon thread running...
+Daemon thread running...
+Daemon thread running...
+Daemon thread running...
+Daemon thread running...
+Daemon thread running...
+Daemon thread running...
+Daemon thread running...
+Daemon thread running...
+Daemon thread running...
+Daemon thread running...
+Daemon thread running...
+Daemon thread running...
+Daemon thread running...
+Daemon thread running...
+Daemon thread running...
+```
+
+- Background Tasks: Tasks that shouldn’t block the application from shutting down.
+  Examples:
+  Garbage Collection: Memory management.
+  Auto-save: Periodically saving temporary drafts.
+  Monitoring/Heartbeats: Checking system health or connection status in the background.
+
+
+## Question 3: 
+
+Output:
+```bash
+Thread is running using a ...!
+```
+
+- **Syntax**: This is a Lambda Expression, a shortcut in to write code blocks (functions) concisely.
+- **Difference**: Your code is just a shorter version of the standard `implements Runnable` approach.
+You don’t need to create a separate class anymore; you just pass the logic directly as a lambda. It’s cleaner and less boilerplate code.

src/main/java/DownloadWorker.java

@@ -21,23 +21,55 @@ public class DownloadWorker implements Runnable {
 
     @Override
     public void run() {
-        // TODO: Record the chunk start time in chunkStatus.
+        // 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.
+        // Print a message that this chunk has started downloading.
+        System.out.println("Starting download for Chunk " + chunkStatus.getChunkId());
 
         while (downloaded < chunkStatus.getChunkSizeMB()) {
-            // TODO: Generate a random sleep delay between min and max delay.
-            // TODO: Sleep for that delay.
-            // TODO: Generate a random download amount for this step.
-            // TODO: Increase downloaded, but do not go beyond chunk size.
-            // TODO: Save the updated downloaded value into chunkStatus.
-            // TODO: Optionally print step-by-step progress.
+
+            // Generate a random sleep delay between min and max delay.
+            long minDelay = config.getMinStepDelayMs();
+            long maxDelay = config.getMaxStepDelayMs();
+            long sleepTime = minDelay + (long) ((maxDelay - minDelay) * random.nextDouble());
+
+            // Sleep for that delay.
+            try {
+                Thread.sleep(sleepTime);
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+
+            // Generate a random download amount for this step.
+            double minStep = config.getMinStepDownloadMB();
+            double maxStep = config.getMaxStepDownloadMB();
+            double downloadAmount = minStep + ((maxStep - minStep) * random.nextDouble());
+
+            // Increase downloaded, but do not go beyond chunk size.
+            if(downloaded + downloadAmount >= chunkStatus.getChunkSizeMB())
+                downloaded = chunkStatus.getChunkSizeMB();
+            else
+                downloaded += downloadAmount;
+
+            // Save the updated downloaded value into chunkStatus.
+            chunkStatus.setDownloadedMB(downloaded);
+
+            // Optionally print step-by-step progress.
+            System.out.print("Chunk " + chunkStatus.getChunkId() + " | downloaded: ");
+            System.out.printf("%.2f%n", downloaded);
         }
 
-        // TODO: Mark the chunk as completed.
-        // TODO: Record the chunk end time in chunkStatus.
-        // TODO: Print a message that this chunk has finished downloading.
+        // Mark the chunk as completed.
+        chunkStatus.setCompleted(true);
+
+        // Record the chunk end time in chunkStatus.
+        chunkStatus.setEndTimeMs(System.currentTimeMillis());
+
+        // Print a message that this chunk has finished downloading.
+        System.out.println("\nChunk " + chunkStatus.getChunkId() + " | COMPLETED!\n");
     }
 
 }

src/main/java/Main.java

@@ -34,45 +34,51 @@ public class Main {
 
             workerThreads.add(workerThread);
 
-            // TODO:
             // Students may print helpful debug information here,
             // for example which chunk is assigned to which worker thread.
+            System.out.println("Assigned Chunk " + chunk.getChunkId()
+                    + " (" + chunk.getChunkSizeMB() + " MB) to " + workerThread.getName());
         }
+        System.out.println();
 
         // 4. Create and start monitor thread
         ProgressMonitor monitor = new ProgressMonitor(config, chunks);
         Thread monitorThread = new Thread(monitor, "Progress-Monitor");
 
-        // TODO:
         // Start the monitor thread before starting the workers
         // so that progress can be displayed while downloading happens.
         //
         // Example idea:
-        // monitorThread.start();
+        monitorThread.start();
 
         // 5. Start worker threads
-        // TODO:
         // Start each worker thread in workerThreads.
         // Use a loop and call start() on each thread.
+        for(Thread thread : workerThreads) {
+            thread.start();
+        }
 
         // 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:
+        // This should be done inside a try-catch block for InterruptedException
+        for (Thread thread : workerThreads) {
+            try {
+                thread.join();
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+        }
         // After all workers finish, the monitor thread may also need to stop.
         // Depending on how ProgressMonitor is implemented, students may:
         // - wait for it to finish on its own, or
         // - add a stopping mechanism in ProgressMonitor later.
         //
         // If your monitor finishes automatically, you may join it here.
-
+        try {
+            monitorThread.join();
+        } catch (InterruptedException e) {
+            throw new RuntimeException(e);
+        }
         // NOTE:
         // this final report may show 0 progress because no worker has actually run yet.
         // Until students complete the thread start/join TODOs above,

src/main/java/ProgressMonitor.java

@@ -16,7 +16,6 @@ public class ProgressMonitor implements Runnable {
 
     @Override
     public void run() {
-        // TODO:
         // Repeatedly check chunk progress until all chunks are completed.
         // In each loop:
         // 1. Read the downloaded size from every chunk
@@ -45,7 +44,7 @@ public class ProgressMonitor implements Runnable {
             }
 
             System.out.printf(
-                    "Progress for %s: %.1f/%.1f MB (%.2f%%), completed chunks: %d/%d%n",
+                    "\nProgress for %s: %.1f/%.1f MB (%.2f%%), completed chunks: %d/%d%n%n",
                     fileName,
                     totalDownloadedMB,
                     (double) totalSizeMB,
@@ -54,9 +53,11 @@ public class ProgressMonitor implements Runnable {
                     chunks.size()
             );
 
-
-            // TODO:
             // If all chunks are completed, print a final message and exit the loop
+            if(completedChunks == chunks.size()){
+                System.out.println(fileName + " downloaded completely.");
+                break;
+            }
 
             try {
                 Thread.sleep(monitorDelayMs);