Example usage for java.io RandomAccessFile getFilePointer

Introduction

In this page you can find the example usage for java.io RandomAccessFile getFilePointer.

Prototype

public native long getFilePointer() throws IOException;

Source Link

Document

Returns the current offset in this file.

Usage

From source file:Main.java

public static void main(String[] argv) throws Exception {
    RandomAccessFile file = new RandomAccessFile("scores.html", "rw");
    for (int i = 1; i <= 6; i++) {
        System.out.println(file.readLine());
    }//from   w ww.  j a va  2 s . c  o  m
    long current = file.getFilePointer();
    file.seek(current + 6);
    file.write("34".getBytes());
    for (int i = 1; i <= 5; i++) {
        System.out.println(file.readLine());
    }
    current = file.getFilePointer();
    file.seek(current + 6);
    file.write("27".getBytes());
    file.close();
}

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From source file:Main.java

public static void main(String[] args) {
    try {//from ww  w.  j  a va  2 s  .  c o m
        // create a new RandomAccessFile with filename Example
        RandomAccessFile raf = new RandomAccessFile("c:/test.txt", "rw");

        // write something in the file
        raf.writeUTF("java2s.com Hello World");

        // set the file pointer at 0 position
        raf.seek(0);

        // read and print the contents of the file
        System.out.println(raf.readUTF());

        // return the file pointer
        System.out.println(raf.getFilePointer());

        // change the position of the file pointer
        raf.seek(5);

        // return the file pointer
        System.out.println(raf.getFilePointer());

        // close the strea and release resources
        raf.close();
    } catch (IOException ex) {
        ex.printStackTrace();
    }

}

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From source file:Main.java

public static void main(String[] args) throws Exception {
    RandomAccessFile raf = new RandomAccessFile("books.dat", "rw");

    String books[] = new String[5];
    books[0] = "A";
    books[1] = "B";
    books[2] = "C";
    books[3] = "D";
    books[4] = "E";

    for (int i = 0; i < books.length; i++) {
        raf.writeUTF(books[i]);/*w ww. ja  va2  s  . c  om*/
    }
    raf.seek(raf.length());
    raf.writeUTF("Servlet & JSP Programming");

    raf.seek(0);

    while (raf.getFilePointer() < raf.length()) {
        System.out.println(raf.readUTF());
    }
}

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From source file:MainClass.java

public static void main(String[] argv) throws IOException {
    RandomAccessFile randomAccessFile = new RandomAccessFile("test.dat", "r");

    randomAccessFile.seek(1000);/*from   w  w  w. ja  v a2  s . co m*/

    FileChannel fileChannel = randomAccessFile.getChannel();

    // This will print "1000"
    System.out.println("file pos: " + fileChannel.position());

    randomAccessFile.seek(500);

    // This will print "500"
    System.out.println("file pos: " + fileChannel.position());

    fileChannel.position(200);

    // This will print "200"
    System.out.println("file pos: " + randomAccessFile.getFilePointer());
}

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From source file:CreateEmployeeFile.java

public static void main(String[] args) throws Exception {
    String[] fnames = { "A", "B", "C" };

    String[] lnames = { "a", "b", "c" };

    String[] addresses = { "Box 100", "55 Street", "6 Lane" };

    byte[] ages = { 46, 59, 32 };

    double[] salaries = { 5.0, 6.0, 3.0 };

    RandomAccessFile raf = new RandomAccessFile("employee.dat", "rw");

    EmployeeRecord er = new EmployeeRecord();

    for (int i = 0; i < fnames.length; i++) {
        er.setFirstName(fnames[i]);/*from  w  ww  .j  a  va2 s  .c o m*/
        er.setLastName(lnames[i]);
        er.setAddress(addresses[i]);
        er.setAge(ages[i]);
        er.setSalary(salaries[i]);
        er.write(raf);
    }
    raf = new RandomAccessFile("employee.dat", "rw");

    er = new EmployeeRecord();

    int numRecords = (int) raf.length() / er.size();

    for (int i = 0; i < numRecords; i++) {
        er.read(raf);

        System.out.print(er.getFirstName() + " ");
        System.out.print(er.getLastName() + " ");
        System.out.print(er.getAddress() + " ");
        System.out.print(er.getAge() + " ");
        System.out.println(er.getSalary());
    }
    raf.seek(0);
    for (int i = 0; i < numRecords; i++) {
        er.read(raf);
        if (er.getAge() >= 55) {
            er.setSalary(0.0);
            raf.seek(raf.getFilePointer() - er.size());
            er.write(raf);
            raf.seek(raf.getFilePointer() - er.size());
            er.read(raf);
        }
        System.out.print(er.getFirstName() + " ");
        System.out.print(er.getLastName() + " ");
        System.out.print(er.getAddress() + " ");
        System.out.print(er.getAge() + " ");
        System.out.println(er.getSalary());
    }

}

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From source file:Main.java

public static void incrementReadCounter(RandomAccessFile raf) throws IOException {
    long currentPosition = raf.getFilePointer();
    raf.seek(0);/*from   www .  j a  v a2s. co  m*/
    int counter = raf.readInt();
    counter++;
    raf.seek(0);
    raf.writeInt(counter);
    raf.seek(currentPosition);
}

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From source file:dk.netarkivet.common.utils.cdx.BinSearch.java

/** Skip to the next line after the given position by
 * reading a line.  Note that if the position is at the start
 * of a line, it will go to the next line.
 *
 * @param in A file to read from/*w w  w .ja  v  a2s .  c o m*/
 * @param pos The position to start at.
 * @return A new position in the file.  The file's pointer (as given by
 * getFilePointer()) is updated to match.
 * @throws IOException If some I/O error occurs
 */
private static long skipToLine(RandomAccessFile in, long pos) throws IOException {
    in.seek(pos);
    in.readLine();
    return in.getFilePointer();
}

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From source file:org.mycontroller.standalone.api.jaxrs.utils.McServerLogFile.java

public static LogFileJson getLogUpdate(Long lastKnownPosition, Long lastNPosition) {
    if (lastNPosition != null && appLogFile.length() > lastNPosition) {
        lastKnownPosition = appLogFile.length() - lastNPosition;
    } else if (lastKnownPosition != null && appLogFile.length() <= lastKnownPosition) {
        return LogFileJson.builder().lastKnownPosition(lastKnownPosition).build();
    }/*from  ww  w .  j  av  a  2s . c  o  m*/
    if (lastKnownPosition == null) {
        lastKnownPosition = 0l;
    }

    //Set maximum limit
    if ((appLogFile.length() - lastKnownPosition) > MAX_POSITION_LIMIT) {
        lastKnownPosition = appLogFile.length() - MAX_POSITION_LIMIT;
    }

    logBuilder.setLength(0);
    // Reading and writing file
    RandomAccessFile readFileAccess = null;
    try {
        readFileAccess = new RandomAccessFile(appLogFile, "r");
        readFileAccess.seek(lastKnownPosition);
        String log = null;
        while ((log = readFileAccess.readLine()) != null) {
            logBuilder.append(log).append("\n");
        }
        lastKnownPosition = readFileAccess.getFilePointer();
    } catch (FileNotFoundException ex) {
        _logger.error("Error,", ex);
    } catch (IOException ex) {
        _logger.error("Error,", ex);
    } finally {
        if (readFileAccess != null) {
            try {
                readFileAccess.close();
            } catch (IOException ex) {
                _logger.error("Error,", ex);
            }
        }
    }
    return LogFileJson.builder().lastKnownPosition(lastKnownPosition).data(logBuilder.toString()).build();
}

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From source file:com.aol.advertising.qiao.util.CommonUtils.java

public static long checksum(RandomAccessFile raFile, int numBytes)
        throws IOException, InsufficientFileLengthException {
    CRC32 _crc = new CRC32();

    long pos = raFile.getFilePointer();
    try {// w  w  w  .  j a  v a 2  s .c  o  m
        byte[] buffer = new byte[numBytes];
        raFile.seek(0);
        int n = raFile.read(buffer);
        if (n < numBytes) {
            String s;
            logger.warn(s = ("not enough data for checksum: current file size=" + n));
            throw new InsufficientFileLengthException(s);
        }

        synchronized (_crc) {
            _crc.reset();
            _crc.update(buffer);

            return _crc.getValue();
        }
    } finally {
        raFile.seek(pos);
    }

}

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From source file:org.mycontroller.standalone.utils.McServerFileUtils.java

public static LogFile getLogUpdate(Long lastKnownPosition, Long lastNPosition) {
    if (lastNPosition != null && appLogFile.length() > lastNPosition) {
        lastKnownPosition = appLogFile.length() - lastNPosition;
    } else if (lastKnownPosition != null && appLogFile.length() <= lastKnownPosition) {
        return LogFile.builder().lastKnownPosition(lastKnownPosition).build();
    }//w  ww  .j  a va 2 s .c o m
    if (lastKnownPosition == null) {
        lastKnownPosition = 0L;
    }

    //Set maximum limit
    if ((appLogFile.length() - lastKnownPosition) > MAX_POSITION_LIMIT) {
        lastKnownPosition = appLogFile.length() - MAX_POSITION_LIMIT;
    }

    logBuilder.setLength(0);
    // Reading and writing file
    RandomAccessFile readFileAccess = null;
    try {
        readFileAccess = new RandomAccessFile(appLogFile, "r");
        readFileAccess.seek(lastKnownPosition);
        String log = null;
        while ((log = readFileAccess.readLine()) != null) {
            logBuilder.append(log).append("\n");
        }
        lastKnownPosition = readFileAccess.getFilePointer();
    } catch (FileNotFoundException ex) {
        _logger.error("Error,", ex);
    } catch (IOException ex) {
        _logger.error("Error,", ex);
    } finally {
        if (readFileAccess != null) {
            try {
                readFileAccess.close();
            } catch (IOException ex) {
                _logger.error("Error,", ex);
            }
        }
    }
    return LogFile.builder().lastKnownPosition(lastKnownPosition).data(logBuilder.toString()).build();
}

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