/**
* Instantiates the query for rscore
*
* @param query contains user query
* @param cmp contains compare structure
* @param resultIndices passes the indices that store the result
* @throws DatabaseException when BerkeleyDB passes errors
* @throws FileNotFoundException when respective .idx or .txt value not found
*/
private void queryRScore(String query, ArrayList<Integer> resultIndices, COMPARE cmp)
throws FileNotFoundException, DatabaseException {
if (cmp == COMPARE.EQUAL) {
query = query.replace("rscore=", "").toLowerCase();
queryDB(query, rscoreIndex, resultIndices);
return;
} else if (cmp == COMPARE.LESS) {
query = query.replace("rscore<", "");
} else {
query = query.replace("rscore>", "");
}
OperationStatus oprStatus;
Database std_db = new Database(rscoreIndex, null, null);
Cursor std_cursor = std_db.openCursor(null, null); // Create new cursor object
if (cmp == COMPARE.LESS) {
for (int n = 0; n < Integer.parseInt(query); n++) {
String searchkey = new String();
searchkey = n + ".0";
DatabaseEntry key = new DatabaseEntry();
DatabaseEntry data = new DatabaseEntry();
oprStatus = std_cursor.getFirst(key, data, LockMode.DEFAULT);
key.setData(searchkey.getBytes());
key.setSize(searchkey.length());
data = new DatabaseEntry();
oprStatus = std_cursor.getSearchKey(key, data, LockMode.DEFAULT);
while (oprStatus == OperationStatus.SUCCESS) {
String s = new String(data.getData());
if (!(resultIndices.contains(Integer.parseInt(s)))) {
resultIndices.add(Integer.parseInt(s));
}
oprStatus = std_cursor.getNextDup(key, data, LockMode.DEFAULT);
}
}
} else {
for (int n = 5; n > Integer.parseInt(query); n--) {
String searchkey = new String();
searchkey = n + ".0";
DatabaseEntry key = new DatabaseEntry();
DatabaseEntry data = new DatabaseEntry();
oprStatus = std_cursor.getFirst(key, data, LockMode.DEFAULT);
key.setData(searchkey.getBytes());
key.setSize(searchkey.length());
data = new DatabaseEntry();
oprStatus = std_cursor.getSearchKey(key, data, LockMode.DEFAULT);
while (oprStatus == OperationStatus.SUCCESS) {
String s = new String(data.getData());
if (!(resultIndices.contains(Integer.parseInt(s)))) {
resultIndices.add(Integer.parseInt(s));
}
oprStatus = std_cursor.getNextDup(key, data, LockMode.DEFAULT);
}
}
}
}
public static Database buildsecondary(Database std) {
// Parse database loaded
try {
io.deleteFile("secondarydb");
// SecondaryDatabases started
DatabaseConfig dbConfig = new DatabaseConfig();
dbConfig.setType(DatabaseType.HASH);
dbConfig.setAllowCreate(true);
dbConfig.setUnsortedDuplicates(true);
Database secdb = new Database("secondarydb", null, dbConfig);
// Cursors started
Cursor stdcursor = std.openCursor(null, null);
Cursor secdbcursor = secdb.openCursor(null, null);
// Key and Data started
DatabaseEntry stdkey = new DatabaseEntry();
DatabaseEntry stddata = new DatabaseEntry();
DatabaseEntry seckey = new DatabaseEntry();
DatabaseEntry secdata = new DatabaseEntry();
while (stdcursor.getNext(stdkey, stddata, LockMode.DEFAULT)
== OperationStatus.SUCCESS) { // Writing into secondary db
String[] key = new String(stdkey.getData()).split(",");
String data = new String(stddata.getData());
// DEBUG:
// System.out.println("key 0:" + key[0] + " key 1:" + key[1] + " data:" + data);
seckey.setData(key[1].getBytes());
OperationStatus operation = secdbcursor.getSearchKey(seckey, secdata, LockMode.DEFAULT);
String b = null;
while (operation == OperationStatus.SUCCESS) {
b = new String(secdata.getData());
secdbcursor.delete();
operation = secdbcursor.getNextDup(seckey, secdata, LockMode.DEFAULT);
}
if (b == null) {
seckey.setData(key[1].getBytes());
secdata.setData(("(" + key[0] + "," + data + ")").getBytes());
secdb.put(null, seckey, secdata);
}
if (b != null) {
secdata.setData(b.concat("(" + key[0] + "," + data + ")").getBytes());
secdb.put(null, seckey, secdata);
}
seckey.setData(null);
secdata.setData(null);
stdkey.setData(null);
stddata.setData(null);
}
// io.debugread(secdb);
return secdb;
} catch (Exception e) {
System.out.println("Error creating <user>,<song,rating> secondary table!\n");
System.out.println(e.getMessage());
}
return null; // SHOULD NEVER HAPPEN
}
/**
* Generic query process
*
* @param query contains parsed query for process
* @param db_name contains database to query
* @param indices passes the indices that store the result
* @throws DatabaseException when BerkeleyDB passes errors
* @throws FileNotFoundException when respective .idx or .txt value not found
*/
private void queryDB(String query, String db_name, ArrayList<Integer> indices)
throws DatabaseException, FileNotFoundException {
OperationStatus oprStatus;
Database std_db = new Database(db_name, null, null);
Cursor std_cursor = std_db.openCursor(null, null); // Create new cursor object
DatabaseEntry key = new DatabaseEntry();
DatabaseEntry data = new DatabaseEntry();
key.setData(query.getBytes());
key.setSize(query.length());
// Returns OperationStatus
oprStatus = std_cursor.getSearchKey(key, data, LockMode.DEFAULT);
while (oprStatus == OperationStatus.SUCCESS) {
String s = new String(data.getData());
if (!(indices.contains(Integer.parseInt(s)))) {
indices.add(Integer.parseInt(s));
}
oprStatus = std_cursor.getNextDup(key, data, LockMode.DEFAULT);
}
std_cursor.close();
std_db.close();
}
