PushbackInputStream

public class PushbackInputStream extends FilterInputStream

A PushbackInputStream adds functionality to another input stream, namely the ability to "push back" or "unread" one byte. This is useful in situations where it is convenient for a fragment of code to read an indefinite number of data bytes that are delimited by a particular byte value; after reading the terminating byte, the code fragment can "unread" it, so that the next read operation on the input stream will reread the byte that was pushed back. For example, bytes representing the characters constituting an identifier might be terminated by a byte representing an operator character; a method whose job is to read just an identifier can read until it sees the operator and then push the operator back to be re-read.

Field Summary

protected byte[] buf The pushback buffer.
protected int pos The position within the pushback buffer from which the next byte will be read.

Inherited Field Summary

Public Constructor Summary

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

Public Method Summary

int
available()
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.
synchronized void
close()
Closes this input stream and releases any system resources associated with the stream.
synchronized void
mark(int readlimit)
Marks the current position in this input stream.
boolean
markSupported()
Tests if this input stream supports the mark and reset methods, which it does not.
int
read()
Reads the next byte of data from this input stream.
int
read(byte[] b, int off, int len)
Reads up to len bytes of data from this input stream into an array of bytes.
synchronized void
reset()
Repositions this stream to the position at the time the mark method was last called on this input stream.
long
skip(long n)
Skips over and discards n bytes of data from this input stream.
void
unread(byte[] b, int off, int len)
Pushes back a portion of an array of bytes by copying it to the front of the pushback buffer.
void
unread(int b)
Pushes back a byte by copying it to the front of the pushback buffer.
void
unread(byte[] b)
Pushes back an array of bytes by copying it to the front of the pushback buffer.

Inherited Method Summary