public SortedMap<Integer, String> find(int from, int to, String regex) throws IOException {
assertIsOpen();
if (regex == null) {
throw new NullPointerException("Regex cannot be null");
}
if (from < 1) {
throw new IllegalArgumentException("'from' must be greater than or equal to 1");
}
if (to < from) {
throw new IllegalArgumentException("'to' must be greater than or equal to 'from'");
}
SortedMap<Integer, String> lines = new TreeMap<>();
List<Long> positions = new ArrayList<>(index);
try {
lock.lock();
raf.seek(positions.get(from - 1));
for (int i = from; i <= to; i++) {
String line = raf.getNextLine(charset);
if (line != null) {
if (line.matches(regex)) {
lines.put(i, line);
}
} else {
break;
}
}
return lines;
} finally {
lock.unlock();
}
}
/**
* Read from line to line
*
* @param from
* @param to
* @return
* @throws IOException
*/
public SortedMap<Integer, String> readLines(int from, int to) throws IOException {
assertIsOpen();
if (from < 1) {
throw new IllegalArgumentException("'from' must be greater than or equal to 1");
}
if (to < from) {
throw new IllegalArgumentException("'to' must be greater than or equal to 'from'");
}
if (from > index.size()) {
throw new IllegalArgumentException("'from' must be less than the file's number of lines");
}
SortedMap<Integer, String> lines = new TreeMap<>();
List<Long> positions = new ArrayList<>(index);
try {
lock.lock();
raf.seek(positions.get(from - 1));
for (int i = from; i <= to; i++) {
String line = raf.getNextLine(charset);
if (line != null) {
lines.put(i, line);
} else {
break;
}
}
return lines;
} finally {
lock.unlock();
}
}
@Override
protected SortedSet<Long> compute() {
SortedSet<Long> index = new TreeSet<>();
try {
if (length < threshold) {
BufferedAccessFile raf = null;
try {
raf = new BufferedAccessFile(file, "r");
raf.seek(start);
// Add the position for 1st line
if (raf.getFilePointer() == 0L) {
index.add(raf.getFilePointer());
}
while (raf.getFilePointer() < end) {
raf.getNextLine();
index.add(raf.getFilePointer());
}
} finally {
if (raf != null) {
raf.close();
}
}
} else {
long start1 = start;
long end1 = start + (length / 2);
long end2 = end;
IndexingTask task1 = new IndexingTask(file, start1, end1, threshold);
task1.fork();
IndexingTask task2 = new IndexingTask(file, end1, end2, threshold);
index.addAll(task2.compute());
index.addAll(task1.join());
}
} catch (IOException ex) {
throw new FileReaderException("Error while index file:" + ex.getMessage(), ex);
}
return index;
}
@Override
public void close() throws IOException {
raf.close();
isClosed = true;
}