Class java.io.PushbackInputStream

java.lang.Object
   |
   +----java.io.InputStream
           |
           +----java.io.FilterInputStream
                   |
                   +----java.io.PushbackInputStream

public class PushbackInputStream
extends FilterInputStream

This class is an input stream filter that provides a buffer into which data can be "unread." An application may unread data at any time by pushing it back into the buffer, as long as the buffer has sufficient room. Subsequent reads will read all of the pushed-back data in the buffer before reading from the underlying input stream.

This functionality is useful when a fragment of code should read an indefinite number of data bytes that are delimited by particular byte values. After reading the terminating byte the code fragment can push it back, so that the next read operation on the input stream will re-read that byte.