PushbackInputStream skip(long) in Java

skip(long): This method is available in the java.io.PushbackInputStream class of Java.

Syntax:

long java.io.PushbackInputStream.skip(long n) throws IOException

This method takes one argument. This method skips over and discards n bytes of data from this input stream.

The skip method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly zero. If n is negative, no bytes are skipped.

Parameters: One parameter is required for this method.

n: the number of bytes to be skipped.

Returns: the actual number of bytes skipped.

Throws:

1. IOException - if the stream has been closed by invoking its close() method, in.skip(n) throws an IOException, or an I/O error occurs.

Approach 1: When no exception

Java

import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;

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

        InputStream in = new InputStream() {

            @Override
            public int read() throws IOException {
                return 10;
            }
        };
        int size = 10;
        PushbackInputStream pushbackInputStream = 
                          new PushbackInputStream(in, size);

        long n = 100L;

        System.out.println(pushbackInputStream.skip(n));
        pushbackInputStream.close();
    }
}

Output:

100

Approach 2: IOException 

Java

package com.PushbackInputStream;

import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;

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

        InputStream in = new InputStream() {

            @Override
            public int read() throws IOException {
                return 10;
            }
        };
        int size = 10;
        PushbackInputStream pushbackInputStream = 
                      new PushbackInputStream(in, size);

        long n = 100L;
        pushbackInputStream.close();
        System.out.println(pushbackInputStream.skip(n));

    }
}

Output:

Exception in thread "main" java.io.IOException: Stream closed
	at java.base/java.io.PushbackInputStream.ensureOpen(PushbackInputStream.java:74)
	at java.base/java.io.PushbackInputStream.skip(PushbackInputStream.java:304)
	at com.PushbackInputStream.PushbackInputStreamskip.main(PushbackInputStreamskip.java:22)

Some other methods of PushbackInputStream

available(): This method returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking the next invocation of a method for this input stream.

mark(int): This method marks the current position in this input stream.

markSupported(): This method tests if this input stream supports the mark and reset methods, which it does not.

PushbackInputStream(InputStream): This method creates a PushbackInputStream with a 1-byte pushback buffer and saves its argument, the input stream, for later use.

PushbackInputStream(InputStream, int): This method creates a PushbackInputStream with a pushback buffer of the specified size, and saves its argument, the input stream, for later use.

read(): This method reads the next byte of data from this input stream.

read(byte[], int, int): This method reads up to len bytes of data from this input stream into an array of bytes.

reset(): This method repositions this stream to the position at the time the mark method was last called on this input stream.

skip(long): This method skips over and discards n bytes of data from this input stream.

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

unread(int): This method pushes back a byte by copying it to the front of the push-back buffer.

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