Java.io.PushbackInputStream Class

Introduction

The Java.io.PushbackInputStream class adds functionality to another input stream, namely the ability to "push back" or "unread" one byte.

Following is the declaration for Java.io.PushbackInputStream class −

public class PushbackInputStream
   extends FilterInputStream

Following are the fields for Java.io.PushbackInputStream class −

protected byte[] buf − This is the pushback buffer.
protected int pos − This is the position within the pushback buffer from which the next byte will be read.
protected InputStream in − This is the input stream to be filtered.

Sr.No.	Constructor & Description
1	PushbackInputStream(InputStream in) This creates a PushbackInputStream and saves its argument, the input stream in, for later use.
2	PushbackInputStream(InputStream in, int size) This creates a PushbackInputStream with a pushback buffer of the specified size, and saves its argument, the input stream in, for later use.

Sr.No.

Constructor & Description

PushbackInputStream(InputStream in)

This creates a PushbackInputStream and saves its argument, the input stream in, for later use.

PushbackInputStream(InputStream in, int size)

This creates a PushbackInputStream with a pushback buffer of the specified size, and saves its argument, the input stream in, for later use.

Sr.No.	Method & Description
1	int available() This method returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next invocation of a method for this input stream.
2	void close() This method closes this input stream and releases any system resources associated with the stream.
3	void mark(int readlimit) This method marks the current position in this input stream.
4	boolean markSupported() This method tests if this input stream supports the mark and reset methods, which it does not.
5	int read() This method reads the next byte of data from this input stream.
6	int read(byte[] b, int off, int len) This method reads up to len bytes of data from this input stream into an array of bytes.
7	void reset() This method repositions this stream to the position at the time the mark method was last called on this input stream.
8	long skip(long n) This method skips over and discards n bytes of data from this input stream.
9	void unread(byte[] b) This method pushes back an array of bytes by copying it to the front of the pushback buffer.
10	void unread(byte[] b, int off, int len) This method pushes back a portion of an array of bytes by copying it to the front of the pushback buffer.
11	void unread(int b) This method pushes back a byte by copying it to the front of the pushback buffer.

This class inherits methods from the following classes −