package net.jcip.examples;
import java.io.File;
import java.io.FileFilter;
import java.util.concurrent.*;
/**
* IndexingService
*
* Shutdown with poison pill
*
* @author Brian Goetz and Tim Peierls
*/
public class IndexingService {
private static final int CAPACITY = 1000;
private static final File POISON = new File("");
private final IndexerThread consumer = new IndexerThread();
private final CrawlerThread producer = new CrawlerThread();
private final BlockingQueue queue;
private final FileFilter fileFilter;
private final File root;
public IndexingService(File root, final FileFilter fileFilter) {
this.root = root;
this.queue = new LinkedBlockingQueue(CAPACITY);
this.fileFilter = new FileFilter() {
public boolean accept(File f) {
return f.isDirectory() || fileFilter.accept(f);
}
};
}
private boolean alreadyIndexed(File f) {
return false;
}
class CrawlerThread extends Thread {
public void run() {
try {
crawl(root);
} catch (InterruptedException e) { /* fall through */
} finally {
while (true) {
try {
queue.put(POISON);
break;
} catch (InterruptedException e1) { /* retry */
}
}
}
}
private void crawl(File root) throws InterruptedException {
File[] entries = root.listFiles(fileFilter);
if (entries != null) {
for (File entry : entries) {
if (entry.isDirectory())
crawl(entry);
else if (!alreadyIndexed(entry))
queue.put(entry);
}
}
}
}
class IndexerThread extends Thread {
public void run() {
try {
while (true) {
File file = queue.take();
if (file == POISON)
break;
else
indexFile(file);
}
} catch (InterruptedException consumed) {
}
}
public void indexFile(File file) {
/*...*/
};
}
public void start() {
producer.start();
consumer.start();
}
public void stop() {
producer.interrupt();
}
public void awaitTermination() throws InterruptedException {
consumer.join();
}
}