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Java LineNumberInputStream mark() Method with Example

LineNumberInputStream Class mark() method: Here, we are going to learn about the mark() method of LineNumberInputStream Class with its syntax and example.
Submitted by Preeti Jain, on April 14, 2020

LineNumberInputStream Class mark() method

• mark() method is available in java.io package.
• mark() method is used to set the current position in this LineNumberInputStream and a subsequent call to reset will reset the stream to the position marked by most recent call of mark() method.
• mark() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
• mark() method does not throw an exception at the time of marking the stream.

Syntax:

    public void mark(int r_limit);

Parameter(s):

• int r_limit – represents the maximum number of bytes that can be read before the mark() position gets invalid.

Return value:

The return type of the method is void, it returns nothing.

Example:

// Java program to demonstrate the example 
// of void mark(int r_limit) method of 
// LineNumberInputStream

import java.io.*;

public class MarkOfLNIS {
 public static void main(String[] args) throws Exception {
  FileInputStream fis_stm = null;
  LineNumberInputStream line_stm = null;
  int val = 0;

  try {
   // Instantiates FileInputStream
   fis_stm = new FileInputStream("D:\\includehelp.txt");
   line_stm = new LineNumberInputStream(fis_stm);

   // By using read() method isto 
   // read the character from line_stm
   char ch1 = (char) line_stm.read();
   char ch2 = (char) line_stm.read();
   char ch3 = (char) line_stm.read();

   System.out.println("ch1: " + ch1);
   System.out.println("ch2: " + ch2);
   System.out.println("ch3: " + ch3);

   // By using mark() method isto
   // set the current position in this
   // line_stm

   System.out.println("line_stm.mark(0): ");
   line_stm.mark(0);
   char ch4 = (char) line_stm.read();
   char ch5 = (char) line_stm.read();

   System.out.println("ch4: " + ch4);
   System.out.println("ch5: " + ch5);
   // By using reset() method isto
   // reset the stream to the position 
   // set by the call mark() method

   System.out.println("line_stm.reset(): ");
   line_stm.reset();
   char ch6 = (char) line_stm.read();
   char ch7 = (char) line_stm.read();
   char ch8 = (char) line_stm.read();
   char ch9 = (char) line_stm.read();


   System.out.println("ch4: " + ch6);
   System.out.println("ch5: " + ch7);
   System.out.println("ch6: " + ch8);
   System.out.println("ch7: " + ch9);

  } catch (Exception ex) {
   System.out.println(ex.toString());
  } finally {
   // with the help of this block is to
   // free all necessary resources linked
   // with the stream
   if (fis_stm != null) {
    fis_stm.close();
    if (line_stm != null) {
     line_stm.close();
    }
   }
  }
 }
}

Output

ch1: J
ch2: A
ch3: V
line_stm.mark(0):
ch4: A
ch5: W
line_stm.reset():
java.io.IOException: mark/reset not supported