implement DownloadWorker.java

src/main/java/DownloadWorker.java

@@ -1,4 +1,5 @@
 import java.util.Random;
+import java.util.concurrent.ThreadLocalRandom;
 
 /**
  * Simulates downloading a single chunk of a file.
@@ -11,33 +12,66 @@ public class DownloadWorker implements Runnable {
 
     private final ChunkStatus chunkStatus;
     private final DownloadConfig config;
-    private final Random random;
 
     public DownloadWorker(ChunkStatus chunkStatus, DownloadConfig config) {
         this.chunkStatus = chunkStatus;
         this.config = config;
-        this.random = new Random();
     }
 
     @Override
     public void run() {
-        // TODO: Record the chunk start time in chunkStatus.
+        long start = System.currentTimeMillis();
+        chunkStatus.setStartTimeMs(start);
+
         double downloaded = 0.0;
 
-        // TODO: Print a message that this chunk has started downloading.
+        System.out.println(
+                "Chunk (id: " + chunkStatus.getChunkId() + ") has started downloading."
+        );
 
         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.
+
+            int randomSleepDelay = ThreadLocalRandom.current().nextInt(
+                    config.getMinStepDelayMs(),
+                    config.getMaxStepDelayMs() + 1
+            );
+
+            try {
+                Thread.sleep(randomSleepDelay);
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+                return;
+            }
+
+            double randomDownloadAmount = ThreadLocalRandom.current().nextDouble(
+                    config.getMinStepDownloadMB(),
+                    config.getMaxStepDownloadMB()
+            );
+
+            downloaded += randomDownloadAmount;
+
+            if (downloaded > chunkStatus.getChunkSizeMB()) {
+                downloaded = chunkStatus.getChunkSizeMB();
+            }
+
+            chunkStatus.setDownloadedMB(downloaded);
+
+            System.out.println(
+                    "Chunk (id: " + chunkStatus.getChunkId() + ") progress: "
+                            + downloaded + " / "
+                            + chunkStatus.getChunkSizeMB() + " MB"
+            );
         }
 
-        // 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);
+
+        long end = System.currentTimeMillis();
+        chunkStatus.setEndTimeMs(end);
+
+        System.out.println(
+                "Chunk (id: " + chunkStatus.getChunkId() + ") has finished downloading. Took: "
+                        + chunkStatus.getDownloadDurationMs() + " ms"
+        );
     }
 
 }