Implement download manager

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 +14,34 @@ 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("[Worker-" + chunkStatus.getChunkId() + "] Started downloading chunk of size: " + String.format("%.2f", chunkStatus.getChunkSizeMB()) + " MB");
 
         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() + random.nextInt(config.getMaxStepDelayMs() - config.getMinStepDelayMs() + 1);
-            // TODO: Generate a random download amount for this step.
+                Thread.sleep(delay);
-            // TODO: Increase downloaded, but do not go beyond chunk size.
+
-            // TODO: Save the updated downloaded value into chunkStatus.
+                double stepDownload = config.getMinStepDownloadMB() + (random.nextDouble() * (config.getMaxStepDownloadMB() - config.getMinStepDownloadMB()));
-            // TODO: Optionally print step-by-step progress.
+
+                downloaded += stepDownload;
+                if (downloaded > chunkStatus.getChunkSizeMB()) {
+                    downloaded = chunkStatus.getChunkSizeMB();
+                }
+
+                chunkStatus.setDownloadedMB(downloaded);
+
+            } catch (InterruptedException e) {
+                System.err.println("Worker-" + chunkStatus.getChunkId() + " was interrupted.");
+                return;
+            }
         }
 
-        // TODO: Mark the chunk as completed.
+        chunkStatus.setCompleted(true);
-        // TODO: Record the chunk end time in chunkStatus.
+        chunkStatus.setEndTimeMs(System.currentTimeMillis());
-        // TODO: Print a message that this chunk has finished downloading.
-    }
 
-}
+        System.out.println("[Worker-" + 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");
@@ -19,65 +18,38 @@ public class Main {
         System.out.println("Chunk count: " + config.getChunkCount());
         System.out.println();
 
-        // 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) {
             DownloadWorker worker = new DownloadWorker(chunk, config);
             Thread workerThread = new Thread(worker, "Worker-" + chunk.getChunkId());
-
             workerThreads.add(workerThread);
 
-            // TODO:
+            System.out.println("Assigned Chunk " + chunk.getChunkId() + " to " + workerThread.getName());
-            // 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:
+        for (Thread thread : workerThreads) {
-        // Start the monitor thread before starting the workers
+            thread.start();
-        // so that progress can be displayed while downloading happens.
+        }
-        //
-        // Example idea:
-        // monitorThread.start();
 
-        // 5. Start worker threads
+        try {
-        // TODO:
+            for (Thread thread : workerThreads) {
-        // Start each worker thread in workerThreads.
+                thread.join();
-        // Use a loop and call start() on each thread.
+            }
+            monitorThread.join();
+        } catch (InterruptedException e) {
+            System.err.println("Main thread interrupted while waiting for workers.");
+        }
 
-        // 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.
-        // 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.
-
-        // 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 ===");
 
@@ -86,22 +58,20 @@ public class Main {
 
         for (ChunkStatus chunk : chunks) {
             downloadedMB += chunk.getDownloadedMB();
-
             if (chunk.isCompleted()) {
                 completedChunks++;
             }
 
-            System.out.println(
+            System.out.printf("Chunk %d: %.2f/%.2f MB (Duration: %d ms)%n",
-                    "Chunk " + chunk.getChunkId()
+                chunk.getChunkId(),
-                            + ": " + chunk.getDownloadedMB()
+                chunk.getDownloadedMB(),
-                            + "/" + chunk.getChunkSizeMB()
+                chunk.getChunkSizeMB(),
-                            + " MB"
+                chunk.getDownloadDurationMs());
-            );
         }
 
         System.out.println();
         System.out.println("Completed chunks: " + completedChunks + "/" + chunks.size());
-        System.out.println("Downloaded total: " + downloadedMB + "/" + config.getTotalSizeMB() + " MB");
+        System.out.printf("Downloaded total: %.2f/%d MB%n", downloadedMB, config.getTotalSizeMB());
         System.out.println("Simulation finished.");
     }
-}
+}

src/main/java/ProgressMonitor.java

@@ -16,33 +16,18 @@ 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
-        // 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
-
-
         while (true) {
             double totalDownloadedMB = 0.0;
             int completedChunks = 0;
 
             for (ChunkStatus chunk : chunks) {
                 totalDownloadedMB += chunk.getDownloadedMB();
-
                 if (chunk.isCompleted()) {
                     completedChunks++;
                 }
             }
 
-            double percent = 0.0;
+            double percent = (totalSizeMB > 0) ? (totalDownloadedMB * 100.0) / totalSizeMB : 100.0;
-            if (totalSizeMB > 0) {
-                percent = (totalDownloadedMB * 100.0) / totalSizeMB;
-            }
 
             System.out.printf(
                     "Progress for %s: %.1f/%.1f MB (%.2f%%), completed chunks: %d/%d%n",
@@ -54,9 +39,10 @@ public class ProgressMonitor implements Runnable {
                     chunks.size()
             );
 
-
+            if (completedChunks == chunks.size()) {
-            // TODO:
+                System.out.println("Monitor: All chunks completed. Shutting down monitor...");
-            // If all chunks are completed, print a final message and exit the loop
+                break;
+            }
 
             try {
                 Thread.sleep(monitorDelayMs);
@@ -66,4 +52,4 @@ public class ProgressMonitor implements Runnable {
             }
         }
     }
-}
+}