77 lines
2.7 KiB
Java
77 lines
2.7 KiB
Java
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;
|
|
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() {
|
|
long startTime = System.currentTimeMillis();
|
|
chunkStatus.setStartTime(startTime);
|
|
|
|
double downloaded = 0.0;
|
|
|
|
System.out.println("Chunk \"" + chunkStatus.getChunkId() + "\" started downloading.");
|
|
|
|
while (downloaded < chunkStatus.getChunkSizeMB()) {
|
|
|
|
try {
|
|
//Generate a random sleep delay between min and max delay.
|
|
int minDelay = config.getMinDelayMs();
|
|
int maxDelay = config.getMaxDelayMs();
|
|
int randomDelay = random.nextInt((maxDelay - minDelay) + 1) + minDelay;
|
|
|
|
//Sleep for that delay.
|
|
Thread.sleep(randomDelay);
|
|
|
|
//Generate a random download amount for this step.
|
|
double minStep = config.getMinStepDelayMs();
|
|
double maxStep = config.getMaxStepDelayMs();
|
|
double randomStep = (maxStep + minStep)*random.nextDouble() + minStep;
|
|
|
|
//Increase downloaded, but do not go beyond chunk size.
|
|
downloaded += randomStep;
|
|
if (downloaded > chunkStatus.getChunkSizeMB()) {
|
|
downloaded = chunkStatus.getChunkSizeMB();
|
|
}
|
|
|
|
//Save the updated downloaded value into chunkStatus.
|
|
chunkStatus.setDownloadedMB(downloaded);
|
|
|
|
//print step-by-step progress.
|
|
System.out.printf("Chunk #%d: Downloaded %.2f / %.2f MB%n",
|
|
chunkStatus.getChunkId(), downloaded, chunkStatus.getChunkSizeMB());
|
|
|
|
} catch (InterruptedException e) {
|
|
System.out.println("Chunk \"" + chunkStatus.getChunkId() + "\" was interrupted!");
|
|
return;
|
|
}
|
|
}
|
|
|
|
//Mark the chunk as completed.
|
|
chunkStatus.setCompleted(true);
|
|
|
|
//Record the chunk end time in chunkStatus.
|
|
long endTime = System.currentTimeMillis();
|
|
chunkStatus.setEndTimeMs(endTime);
|
|
|
|
//Print a message that this chunk has finished downloading.
|
|
System.out.println("Chunk \"" + chunkStatus.getChunkId() + "\" has finished downloading.");
|
|
}
|
|
|
|
} |