1. Description
2. Field Summary
3. Constructor Summary
4. Method Summary
5. Constructor Details
   1. PushbackReader(Reader, int)
   2. PushbackReader(Reader)
6. Method Details
   1. read()
   2. unread(int)
   3. unread(char[], int, int)
   4. unread(char[])
   5. ready()
   6. mark(int)
   7. reset()
   8. markSupported()
   9. close()

All Implemented Interfaces:

Closeable, AutoCloseable, Readable

• Field Summary

  Fields declared in class java.io.FilterReader

  in

  Fields declared in class java.io.Reader

  lock

• Constructor Summary

  Constructors
  Constructor

  Description

  PushbackReader(Reader in)

  Creates a new pushback reader with a one-character pushback buffer.

  PushbackReader(Reader in, int size)

  Creates a new pushback reader with a pushback buffer of the given size.

• Method Summary

  All MethodsInstance MethodsConcrete Methods

  Modifier and Type

  Method

  Description

  void

  close()

  Closes the stream and releases any system resources associated with it.

  void

  mark(int readAheadLimit)

  Marks the present position in the stream.

  boolean

  markSupported()

  Tells whether this stream supports the mark() operation, which it does not.

  int

  read()

  Reads a single character.

  boolean

  ready()

  Tells whether this stream is ready to be read.

  void

  reset()

  Resets the stream.

  void

  unread(char[] cbuf)

  Pushes back an array of characters by copying it to the front of the pushback buffer.

  void

  unread(char[] cbuf, int off, int len)

  Pushes back a portion of an array of characters by copying it to the front of the pushback buffer.

  void

  unread(int c)

  Pushes back a single character by copying it to the front of the pushback buffer.

  Methods declared in class java.io.FilterReader

  read, skip

  Methods declared in class java.io.Reader

  nullReader, of, read, read, transferTo

  Methods declared in class java.lang.Object

  clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

• Constructor Details

  • PushbackReader

    public PushbackReader(Reader in, int size)

    Creates a new pushback reader with a pushback buffer of the given size.

    Parameters:

    in - The reader from which characters will be read

    size - The size of the pushback buffer

    Throws:

    IllegalArgumentException - if size <= 0

  • PushbackReader

    public PushbackReader(Reader in)

    Creates a new pushback reader with a one-character pushback buffer.

    Parameters:

    in - The reader from which characters will be read

• Method Details

  • read

    public int read() throws IOException

    Reads a single character.

    Overrides:

    read in class FilterReader

    Returns:

    The character read, or -1 if the end of the stream has been reached

    Throws:

    IOException - If an I/O error occurs

  • unread

    public void unread(int c) throws IOException

    Pushes back a single character by copying it to the front of the pushback buffer. After this method returns, the next character to be read will have the value (char)c.

    Parameters:

    c - The int value representing a character to be pushed back

    Throws:

    IOException - If the pushback buffer is full, or if some other I/O error occurs

  • unread

    public void unread(char[] cbuf, int off, int len) throws IOException

    Pushes back a portion of an array of characters by copying it to the front of the pushback buffer. After this method returns, the next character to be read will have the value cbuf[off], the character after that will have the value cbuf[off+1], and so forth.

    Parameters:

    cbuf - Character array

    off - Offset of first character to push back

    len - Number of characters to push back

    Throws:

    IOException - If there is insufficient room in the pushback buffer, or if some other I/O error occurs

  • unread

    public void unread(char[] cbuf) throws IOException

    Pushes back an array of characters by copying it to the front of the pushback buffer. After this method returns, the next character to be read will have the value cbuf[0], the character after that will have the value cbuf[1], and so forth.

    Parameters:

    cbuf - Character array to push back

    Throws:

    IOException - If there is insufficient room in the pushback buffer, or if some other I/O error occurs

  • ready

    public boolean ready() throws IOException

    Tells whether this stream is ready to be read.

    Overrides:

    ready in class FilterReader

    Returns:

    True if the next read() is guaranteed not to block for input, false otherwise. Note that returning false does not guarantee that the next read will block.

    Throws:

    IOException - If an I/O error occurs

  • mark

    public void mark(int readAheadLimit) throws IOException

    Marks the present position in the stream. The mark for class PushbackReader always throws an exception.

    Overrides:

    mark in class FilterReader

    Parameters:

    readAheadLimit - Limit on the number of characters that may be read while still preserving the mark. After reading this many characters, attempting to reset the stream may fail.

    Throws:

    IOException - Always, since mark is not supported

  • reset

    public void reset() throws IOException

    Resets the stream. The reset method of PushbackReader always throws an exception.

    Overrides:

    reset in class FilterReader

    Throws:

    IOException - Always, since reset is not supported

  • markSupported

    public boolean markSupported()

    Tells whether this stream supports the mark() operation, which it does not.

    Overrides:

    markSupported in class FilterReader

    Returns:

    true if and only if this stream supports the mark operation.

  • close

    public void close() throws IOException

    Closes the stream and releases any system resources associated with it. Once the stream has been closed, further read(), unread(), ready(), or skip() invocations will throw an IOException. Closing a previously closed stream has no effect. This method will block while there is another thread blocking on the reader.

    Specified by:

    close in interface AutoCloseable

    Specified by:

    close in interface Closeable

    Specified by:

    close in class Reader

    Throws:

    IOException - If an I/O error occurs

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