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.

Class declaration

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

public class PushbackInputStream
   extends FilterInputStream

Field

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.

Class constructors

S.N.	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.

Class methods

S.N.	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.

Methods inherited

This class inherits methods from the following classes:

• Java.io.FilterInputStream
• Java.io.Object