class:PushbackReader [NONE]

All Implemented Interfaces:: Closeable, AutoCloseable, Readable

public class PushbackReaderextends FilterReader

A character-stream reader that allows characters to be pushed back into the stream.

Since:: 1.1

constructor:PushbackReader(java.io.Reader,int) [NONE]

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

constructor:PushbackReader(java.io.Reader) [NONE]

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:read() [NONE]

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

method:read(char[],int,int) [NONE]

read

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

Reads characters into a portion of an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.

If len is zero, then no characters are read and 0 is returned; otherwise, there is an attempt to read at least one character. If no character is available because the stream is at its end, the value -1 is returned; otherwise, at least one character is read and stored into cbuf.

Overrides:: read in class FilterReader
Parameters:: cbuf - Destination buffer; off - Offset at which to start storing characters; len - Maximum number of characters to read
Returns:: The number of characters read, or -1 if the end of the stream has been reached
Throws:: IOException - If an I/O error occurs

method:unread(int) [NONE]

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

method:unread(char[],int,int) [NONE]

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

method:unread(char[]) [NONE]

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

method:ready() [NONE]

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

method:mark(int) [NONE]

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

method:reset() [NONE]

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

method:markSupported() [NONE]

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.

method:close() [NONE]

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
Overrides:: close in class FilterReader
Throws:: IOException - If an I/O error occurs

method:skip(long) [NONE]

skip

public long skip (long n) throws IOException

Skips characters. This method will block until some characters are available, an I/O error occurs, or the end of the stream is reached. If the stream is already at its end before this method is invoked, then no characters are skipped and zero is returned.

Overrides:: skip in class FilterReader
Parameters:: n - The number of characters to skip
Returns:: The number of characters actually skipped
Throws:: IOException - If an I/O error occurs