Merge pull request 'Complete assignment' (#1) from develop into main

Reviewed-on: Matin-Ardestani/HW-08-Basic-Multithreading#1

.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 +1,51 @@
+## Question 1
+output:
+```angular2html
+Calling run()
+Running in: main
+Calling start()
+Running in: Thread-2
+```
+note that there will be a 100ms pause before calling start.
+
+when calling `t1.run()` no other thread will be created and `Thread.currentThread().getName()` returns the thread that was already running. 
+
+but when calling `t2.start()` a branch new thread gets created alongside the main one named _Thread-2_.
+
+## Question 2
+output:
+```angular2html
+Main thread ends.
+Daemon thread running...
+```
+when we use  `setDaemon(true)` method for a thread it means that there is no need for _JVM_ to wait for this thread to finish its job and end the program.
+
+So if we call `thread.start()` after setting the thread a daemon one a new daemon thread gets created and as soon as there is time for the main thread (because of the 0.5 second pause) it finishes the program.
+
+If we were not to set the thread a daemon, we could see the expression `Daemon thread running...` 20 times which 0.5 second pauses.
+
+It is useful for health check and monitoring, cache eviction etc...
+
+## Question 3
+output:
+```angular2html
+Thread is running using a ...!
+```
+`() -> { ... }` is called a _Lambda Expression_.
+If we were to write this functionality in a simple way and not in lambda:
+```java
+public class ThreadDemo {
+    
+    static class MyRunnable implements Runnable {
+        @Override
+        public void run() {
+            System.out.println("Thread is running using a ...!");
+        }
+    }
+    
+    public static void main(String[] args) {
+        Thread thread = new Thread(new MyRunnable());
+        thread.start();
+    }
+}
+```

src/main/java/DownloadWorker.java

@@ -21,23 +21,34 @@ 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(chunkStatus.getChunkId() + " started downloading...");
 
         while (downloaded < chunkStatus.getChunkSizeMB()) {
-            // TODO: Generate a random sleep delay between min and max delay.
+            int delay = config.getMinStepDelayMs() + random.nextInt(config.getMaxStepDelayMs() - config.getMinStepDelayMs() + 1);
-            // TODO: Sleep for that delay.
+
-            // TODO: Generate a random download amount for this step.
+            try {
-            // TODO: Increase downloaded, but do not go beyond chunk size.
+                Thread.sleep(delay);
-            // TODO: Save the updated downloaded value into chunkStatus.
+            } catch (InterruptedException e) {
-            // TODO: Optionally print step-by-step progress.
+                throw new RuntimeException(e);
             }
 
-        // TODO: Mark the chunk as completed.
+            double downloadAmount = random.nextDouble(chunkStatus.getChunkSizeMB());
-        // TODO: Record the chunk end time in chunkStatus.
+            downloaded += downloadAmount;
-        // TODO: Print a message that this chunk has finished downloading.
+            if(downloaded > chunkStatus.getChunkSizeMB())
+                downloaded = chunkStatus.getChunkSizeMB();
+
+            chunkStatus.setDownloadedMB(downloaded);
+            System.out.printf("%s progress: %.2f / %.2f MB\n",
+                    chunkStatus.getChunkId(), downloaded, chunkStatus.getChunkSizeMB());
+        }
+
+        chunkStatus.setCompleted(true);
+        chunkStatus.setEndTimeMs(System.currentTimeMillis());
+        System.out.println(chunkStatus.getChunkId() + " finished downloading.");
     }
 
 }

src/main/java/Main.java

@@ -34,48 +34,35 @@ public class Main {
 
             workerThreads.add(workerThread);
 
-            // TODO:
+            System.out.printf("Chunk: %d, Thread: %s\n",
-            // Students may print helpful debug information here,
+                    chunk.getChunkId(), workerThread.getName());
-            // 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");
 
-        // TODO:
+        monitorThread.start();
-        // 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 workerThread : workerThreads){
-        // Start each worker thread in workerThreads.
+            workerThread.start();
-        // Use a loop and call start() on each thread.
+        }
 
         // 6. Wait for workers to finish
-        // TODO:
+        for(Thread workerThread : workerThreads){
-        // Wait for all worker threads to complete by calling join().
+            try {
-        // This should be done inside a try-catch block for InterruptedException.
+                workerThread.join();
-        //
+            } catch(InterruptedException e){
-        // Hint:
+                throw new RuntimeException(e);
-        // for (Thread thread : workerThreads) {
+            }
-        //     thread.join();
+        }
-        // }
 
-        // TODO:
+        try {
-        // After all workers finish, the monitor thread may also need to stop.
+            monitorThread.join();
-        // Depending on how ProgressMonitor is implemented, students may:
+        } catch(InterruptedException e){
-        // - wait for it to finish on its own, or
+            throw new RuntimeException(e);
-        // - 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();

src/main/java/ProgressMonitor.java

@@ -16,17 +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
-        // 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;
@@ -55,8 +44,13 @@ 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 are completed. Downloaded file successfully.");
+                for(ChunkStatus chunk : chunks){
+                    System.out.println(chunk);
+                }
+                break;
+            }
 
             try {
                 Thread.sleep(monitorDelayMs);