public class WordIndex {
private static Logger log = Logger.getLogger(Dictionary.class.getName());
private HashMap<String, ArrayList<FilePositions>> idx =
new HashMap<String, ArrayList<FilePositions>>();
private Dictionary dict = Dictionary.getInstance();
class FilePositions {
long fileid;
ArrayList<Long> poslist;
}
public boolean addWord(String str, long fileid, long pos) {
/*
* Filter out certain strings. e.g. words that are either very rare (e.g.
* spelling mistakes) or extremely common "stop words".
* http://en.wikipedia.org/wiki/Stop_words
*
* Our definition of stop words is completely arbitrary. It has more to do
* with what kind of computation we can do on a single appengine node.
*
* Ideally we would not ignore any words, but that will require sharding the
* word index across a number of serving machines.
*/
if (str.length() < 3) return false;
int freq = dict.getFrequency(str);
if (freq == 0 || freq > 90000) return false;
ArrayList<FilePositions> fplist = idx.get(str);
if (fplist == null) {
fplist = new ArrayList<FilePositions>();
idx.put(str, fplist);
}
if (fplist.size() == 0 || fplist.get(fplist.size() - 1).fileid != fileid) {
FilePositions fp = new FilePositions();
fp.fileid = fileid;
fp.poslist = new ArrayList<Long>();
fplist.add(fp);
}
fplist.get(fplist.size() - 1).poslist.add(pos);
return true;
}
private void writeMap() {
for (Map.Entry<String, ArrayList<FilePositions>> e : idx.entrySet()) {
System.out.print(e.getKey());
for (FilePositions fp : e.getValue()) {
System.out.print(" " + fp.fileid);
for (Long pos : fp.poslist) System.out.print(" " + pos);
System.out.print(" . ");
}
System.out.println();
}
}
public void initFromText(String fname) {
long count = 0;
long last = 0;
long values = 0;
try {
DataInputStream is = new DataInputStream(new FileInputStream(fname));
while (true) {
long fileid;
try {
fileid = is.readLong();
} catch (EOFException e) {
break;
}
long len = is.readLong();
byte[] buf = new byte[(int) len];
is.read(buf);
String str = new String(buf);
String[] tokens = str.split("[^a-zA-Z]+");
int pos = 0;
for (String t : tokens) {
t = new String(t.toLowerCase());
boolean added = addWord(t, fileid, pos++);
if (added) {
values++;
}
}
count += len;
if (count > last + 100 * 1024 * 1024) {
System.err.printf(
"processed = %d Mb, # words = %d, # positions = %d, lastfileid = %d\n",
count / 1024 / 1024, idx.size(), values, fileid);
last = count;
}
}
} catch (IOException e) {
log.log(Level.WARNING, "Error: " + fname, e);
} finally {
}
}
public static void main(String args[]) {
WordIndex wi = new WordIndex();
wi.initFromText(args[0]);
wi.writeMap();
}
}
@Before
public void setup() throws FileNotFoundException {
Dictionary dict = Dictionary.getInstance(new File("words.txt"));
BoardDescription board = new WordsWithFriendsBoard();
game = new PlayingBoard(board, dict);
}