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Java FilterInputStream mark() Method with Example

FilterInputStream Class mark() method: Here, we are going to learn about the mark() method of FilterInputStream Class with its syntax and example.
Submitted by Preeti Jain, on April 02, 2020

FilterInputStream Class mark() method

• mark() method is available in java.io package.
• mark() method is used to set the current mark in this FilterInputStream and a subsequent call to reset() will reset the stream to the position marked most recently.
• 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 limit on the number of bytes that can be read before the mark 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 
// FilterInputStream

import java.io.*;

public class MarkOfFIS {
 public static void main(String[] args) throws Exception {
  FileInputStream fis_stm = null;
  FilterInputStream fil_stm = null;

  try {
   // Instantiates FileInputStream and 
   // FilterInputStream
   fis_stm = new FileInputStream("D:\\includehelp.txt");
   fil_stm = new BufferedInputStream(fis_stm);

   // By using read() method isto 
   // read the character from car_stm
   char ch1 = (char) fil_stm.read();
   char ch2 = (char) fil_stm.read();
   char ch3 = (char) fil_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
   // fil_stm
   System.out.println("fil_stm.mark(0): ");
   fil_stm.mark(0);
   char ch4 = (char) fil_stm.read();
   char ch5 = (char) fil_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("fil_stm.reset(): ");
   fil_stm.reset();
   char ch6 = (char) fil_stm.read();
   char ch7 = (char) fil_stm.read();
   char ch8 = (char) fil_stm.read();
   char ch9 = (char) fil_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 (fil_stm != null) {
     fil_stm.close();
    }
   }
  }
 }
}

Output

ch1: J
ch2: a
ch3: v
fil_stm.mark(0):
ch4: a
ch5: W
fil_stm.reset():
ch4: a
ch5: W
ch6: o
ch7: r