public static void main(String[] args) {
Date start = new Date();
if (args.length < 3) {
System.out.println("Wrong number of arguments:\n" + USAGE);
return;
}
// get # threads
int tc = Integer.parseInt(args[0]);
String outfile = args[1];
// make a threadsafe queue of all files to process
ConcurrentLinkedQueue<String> files = new ConcurrentLinkedQueue<String>();
for (int i = 2; i < args.length; i++) {
files.add(args[i]);
}
// hastable for results
Hashtable<String, Integer> results = new Hashtable<String, Integer>(HASH_SIZE, LF);
// spin up the threads
Thread[] workers = new Thread[tc];
for (int i = 0; i < tc; i++) {
workers[i] = new Worker(files, results);
workers[i].start();
}
// wait for them to finish
try {
for (int i = 0; i < tc; i++) {
workers[i].join();
}
} catch (Exception e) {
System.out.println("Caught Exception: " + e.getMessage());
}
// terminal output
Date end = new Date();
System.out.println(end.getTime() - start.getTime() + " total milliseconds");
System.out.println(results.size() + " unique words");
// sort results for easy comparison/verification
List<Map.Entry<String, Integer>> sorted_results =
new ArrayList<Map.Entry<String, Integer>>(results.entrySet());
Collections.sort(sorted_results, new KeyComp());
// file output
try {
PrintStream out = new PrintStream(outfile);
for (int i = 0; i < sorted_results.size(); i++) {
out.println(sorted_results.get(i).getKey() + "\t" + sorted_results.get(i).getValue());
}
} catch (Exception e) {
System.out.println("Caught Exception: " + e.getMessage());
}
}
public void run() {
// each file is processed into a local hash table and then merged with the global results
// this will cause much less contention on the global table, but still avoids a sequential
// update
Hashtable<String, Integer> local_results =
new Hashtable<String, Integer>(WordCountJ.HASH_SIZE, WordCountJ.LF);
// grab a file to work on
String cf;
while ((cf = files.poll()) != null) {
try {
BufferedReader input = new BufferedReader(new FileReader(cf));
String text;
// well go line-by-line... maybe this is not the fastest
while ((text = input.readLine()) != null) {
// parse words
Matcher matcher = pattern.matcher(text);
while (matcher.find()) {
String word = matcher.group(1);
if (local_results.containsKey(word)) {
local_results.put(word, 1 + local_results.get(word));
} else {
local_results.put(word, 1);
}
}
}
input.close();
} catch (Exception e) {
System.out.println(" caught a " + e.getClass() + "\n with message: " + e.getMessage());
return;
}
// merge local hashmap with shared one,could have a
// seperate thread do this but that might be cheating
Iterator<Map.Entry<String, Integer>> updates = local_results.entrySet().iterator();
while (updates.hasNext()) {
Map.Entry<String, Integer> kv = updates.next();
String k = kv.getKey();
Integer v = kv.getValue();
synchronized (results) {
if (results.containsKey(k)) {
results.put(k, v + results.get(k));
} else {
results.put(k, v);
}
}
}
local_results.clear();
}
}