complete

.idea/misc.xml

@@ -8,7 +8,7 @@
       </list>
     </option>
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_21" default="true" project-jdk-name="21" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_25" default="true" project-jdk-name="25" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/out" />
   </component>
 </project>

Report.md

@@ -0,0 +1,63 @@
+## Answers to Theoretical Questions
+
+### 1. `start()` vs `run()`
+
+**Output:**
+```
+Calling run()
+Running in: main
+Calling start()
+Running in: Thread-2
+```
+
+- When we call `run()` directly, it's just a normal method call.  
+  No new thread is created – everything happens inside the current thread (here `main`).  
+  That's why the printed thread name is `main`.
+
+- Calling `start()` actually creates a brand new thread and then runs `run()` inside that new thread.  
+  So the output shows that `Thread-2` is the one executing the code.
+
+- The main difference:  
+  `run()` → synchronous, runs in the caller thread.  
+  `start()` → asynchronous, spawns a separate thread and runs `run()` there.
+
+---
+
+### 2. Daemon Threads
+
+**Program output (when `setDaemon(true)` is used):**
+```
+Main thread ends.
+Daemon thread running...
+```
+(Only a few lines might appear before the program exits.)
+
+- By marking the thread as a daemon, we tell the JVM: *"This thread is doing background work – don't wait for it."*  
+  As soon as all **user threads** finish, the JVM shuts down, even if daemon threads are still running.  
+  Here `main` is a user thread, so after it prints its message and ends, the program terminates quickly.
+
+- If we **remove** `thread.setDaemon(true)`, the thread becomes a normal user thread.  
+  Then the JVM will wait for it to finish all 20 iterations before exiting.  
+  We'd see `"Daemon thread running..."` printed 20 times.
+
+- Real‑life examples of daemon threads:  
+  - The **garbage collector** in Java – runs in the background but won't stop the JVM from closing.  
+  - **Auto‑save** in a text editor – saves periodically but shouldn't block the program from closing.
+
+---
+
+### 3. A shorter way to create threads
+
+**Output:**
+```
+Thread is running using a ...!
+```
+
+- The `() -> { ... }` part is a **lambda expression**.  
+  It's a compact way to write an anonymous function.
+
+- Instead of creating a whole new class that implements `Runnable` (or extending `Thread`), we can just pass the body of `run()` directly inside `new Thread(...)`.  
+  This makes the code much shorter and easier to read, especially for one‑off tasks.
+
+- Lambdas are perfect for simple jobs, but if the task is complex or needs to be reused, a separate class might be better.
+

src/main/java/DownloadWorker.java

@@ -1,12 +1,5 @@
 import java.util.Random;
 
-/**
- * Simulates downloading a single chunk of a file.
- *
- * <p>This class is intentionally provided as a skeleton for students.
- * The main multithreading and simulation logic should be completed
- * in the run() method.</p>
- */
 public class DownloadWorker implements Runnable {
 
     private final ChunkStatus chunkStatus;
@@ -21,23 +14,29 @@ public class DownloadWorker implements Runnable {
 
     @Override
     public void run() {
-        // TODO: Record the chunk start time in chunkStatus.
+        chunkStatus.setStartTimeMs(System.currentTimeMillis());
+        System.out.println("Chunk " + chunkStatus.getChunkId() + " started downloading.");
         double downloaded = 0.0;
+        double chunkSize = chunkStatus.getChunkSizeMB();
 
-        // TODO: Print a message that this chunk has started downloading.
+        while (downloaded < chunkSize) {
+            int delay = config.getMinStepDelayMs()
+                    + random.nextInt(config.getMaxStepDelayMs() - config.getMinStepDelayMs() + 1);
+            try {
+                Thread.sleep(delay);
+            }
+            catch (InterruptedException e) {
+                break;
+            }
+            double step = config.getMinStepDownloadMB()
+                    + random.nextDouble() * (config.getMaxStepDownloadMB() - config.getMinStepDownloadMB());
 
-        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.
+            downloaded = Math.min(downloaded + step, chunkSize);
+            chunkStatus.setDownloadedMB(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.
+        chunkStatus.setCompleted(true);
+        chunkStatus.setEndTimeMs(System.currentTimeMillis());
+        System.out.println("Chunk " + chunkStatus.getChunkId() + " finished downloading.");
     }
 
 }

src/main/java/Main.java

@@ -5,7 +5,6 @@ public class Main {
     public static void main(String[] args) {
         System.out.println("=== Simulated Download Manager ===");
 
-        // 1. Read config
         DownloadConfig config;
         try {
             config = ConfigReader.readConfig("download_config.txt");
@@ -18,14 +17,13 @@ public class Main {
         System.out.println("Total size (MB): " + config.getTotalSizeMB());
         System.out.println("Chunk count: " + config.getChunkCount());
         System.out.println();
+        System.out.println("Starting download...\n");
 
-        // 2. Create chunks
         List<ChunkStatus> chunks = ChunkUtils.createChunks(
                 config.getTotalSizeMB(),
                 config.getChunkCount()
         );
 
-        // 3. Create worker threads
         List<Thread> workerThreads = new ArrayList<>();
 
         for (ChunkStatus chunk : chunks) {
@@ -33,51 +31,32 @@ public class Main {
             Thread workerThread = new Thread(worker, "Worker-" + chunk.getChunkId());
 
             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: Worker-" + chunk.getChunkId() + " -> Chunk " + chunk.getChunkId());
         }
 
-        // 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 t : workerThreads) {
+            t.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();
-        // }
+        for (Thread t : workerThreads) {
+            try {
+                t.join();
+            } catch (InterruptedException e) {
+                System.out.println("Main thread interrupted while waiting for workers.");
+            }
+        }
 
-        // TODO:
-        // 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) {
+            System.out.println("Main thread interrupted while waiting for monitor.");
+        }
 
-        // NOTE:
-        // this final report may show 0 progress because no worker has actually run yet.
-        // Until students complete the thread start/join TODOs above,
-
-        // 7. Print final report
         System.out.println();
         System.out.println("=== Final Report ===");
 
@@ -103,5 +82,6 @@ public class Main {
         System.out.println("Completed chunks: " + completedChunks + "/" + chunks.size());
         System.out.println("Downloaded total: " + downloadedMB + "/" + config.getTotalSizeMB() + " MB");
         System.out.println("Simulation finished.");
+        System.out.println("Thank you for using the download manager!");
     }
 }

src/main/java/ProgressMonitor.java

@@ -6,26 +6,19 @@ public class ProgressMonitor implements Runnable {
     private final int totalSizeMB;
     private final List<ChunkStatus> chunks;
     private final long monitorDelayMs;
+    private final long startTimeMs;
 
     public ProgressMonitor(DownloadConfig config, List<ChunkStatus> chunks) {
         this.fileName = config.getFileName();
         this.totalSizeMB = config.getTotalSizeMB();
         this.chunks = chunks;
         this.monitorDelayMs = 500;
+        this.startTimeMs = System.currentTimeMillis();
     }
 
     @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
-        // 2. Add all downloaded amounts to totalDownloadedMB
-        // 3. Count completed chunks
-        // 4. Print a progress message
-        // 5. If completedChunks == chunks.size(), print a final monitor message and stop
-        // 6. Otherwise sleep for monitorDelayMs and continue
-
+        System.out.println("=== Download Progress ===");
 
         while (true) {
             double totalDownloadedMB = 0.0;
@@ -44,19 +37,36 @@ public class ProgressMonitor implements Runnable {
                 percent = (totalDownloadedMB * 100.0) / totalSizeMB;
             }
 
-            System.out.printf(
-                    "Progress for %s: %.1f/%.1f MB (%.2f%%), completed chunks: %d/%d%n",
+            long elapsedMs = System.currentTimeMillis() - startTimeMs;
+            double elapsedSec = elapsedMs / 1000.0;
+            double speedMBps = (elapsedSec > 0) ? (totalDownloadedMB / elapsedSec) : 0.0;
+            double remainingMB = totalSizeMB - totalDownloadedMB;
+            double etaSec = (speedMBps > 0) ? (remainingMB / speedMBps) : 0.0;
+
+            int barLength = 30;
+            int filled = (int) (percent / 100.0 * barLength);
+            StringBuilder bar = new StringBuilder("[");
+            for (int i = 0; i < barLength; i++) {
+                bar.append(i < filled ? "=" : " ");
+            }
+            bar.append("]");
+
+            System.out.printf("\r%s %s %.1f/%.1f MB (%.1f%%) | Speed: %.1f MB/s | ETA: %.0fs | Chunks: %d/%d",
+                    bar.toString(),
                     fileName,
                     totalDownloadedMB,
                     (double) totalSizeMB,
                     percent,
+                    speedMBps,
+                    etaSec,
                     completedChunks,
                     chunks.size()
             );
 
-
-            // TODO:
-            // If all chunks are completed, print a final message and exit the loop
+            if (completedChunks == chunks.size()) {
+                System.out.println("Monitor: All chunks completed.");
+                break;
+            }
 
             try {
                 Thread.sleep(monitorDelayMs);