PushbackReader mark(int) in Java

mark(int): This method is available in the java.io.PushbackReader class of Java.

Syntax:

void java.io.PushbackReader.mark(int readAheadLimit) throws IOException

This method takes one argument. This method marks the present position in the stream. The mark for class PushbackReader always throws an exception.

Parameters: One parameter is required for this method.

readAheadLimit: Limit the number of characters that may be read while still preserving the mark. After reading this many characters, attempting to reset the stream may fail.

Returns: NA

Throws:

IOException - Always, since the mark is not supported.

Approach

Java

package com.PushbackReader;

import java.io.IOException;
import java.io.PipedReader;
import java.io.PushbackReader;
import java.io.Reader;

public class PushbackReadermark {
    public static void main(String[] args) throws IOException {

        Reader in = new PipedReader();
        PushbackReader pushbackReader = new PushbackReader(in);

        int readAheadLimit = 10;
        pushbackReader.mark(readAheadLimit);

        System.out.println("Successfully mark the read limit");

        pushbackReader.close();
    }
}

Output:

Exception in thread "main" java.io.IOException: mark/reset not supported
	at java.base/java.io.PushbackReader.mark(PushbackReader.java:219)
	at com.PushbackReader.PushbackReadermark.main(PushbackReadermark.java:15)

Some other methods of PushbackReader

close(): This method closes the stream and releases any system resources associated with it.

mark(int): This method marks the present position in the stream.

markSupported(): This method tells whether this stream supports the mark() operation, which it does not.

PushbackReader(Reader): This method creates a new pushback reader with a one-character pushback buffer.

PushbackReader(Reader, int): This method creates a new pushback reader with a pushback buffer of the given size.

read(): This method reads a single character.

read(char[], int, int): This method reads characters into a portion of an array.

ready(): This method tells whether this stream is ready to be read.

reset(): This method resets the stream.

skip(long): This method skips characters

unread(char[]): This method pushes back an array of characters by copying it to the front of the pushback buffer.

unread(int): This method pushes back a single character by copying it to the front of the pushback buffer.

unread(char[], int, int):  This method pushes back a portion of an array of characters by copying it to the front of the pushback buffer.