public class PushbackReader extends FilterReader
A character-stream reader that allows characters to be pushed back into the stream.
in
lock
public PushbackReader(Reader in, int size)
Creates a new pushback reader with a pushback buffer of the given size.
in
- The reader from which characters will be readsize
- The size of the pushback bufferIllegalArgumentException
- if size <= 0
public PushbackReader(Reader in)
Creates a new pushback reader with a one-character pushback buffer.
in
- The reader from which characters will be readpublic int read() throws IOException
Reads a single character.
read
in class FilterReader
IOException
- If an I/O error occurspublic int read(char[] cbuf, int off, int len) throws IOException
Reads characters into a portion of an array.
read
in class FilterReader
cbuf
- Destination bufferoff
- Offset at which to start writing characterslen
- Maximum number of characters to readIOException
- If an I/O error occurspublic 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
.
c
- The int value representing a character to be pushed backIOException
- If the pushback buffer is full, or if some other I/O error occurspublic 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.
cbuf
- Character arrayoff
- Offset of first character to push backlen
- Number of characters to push backIOException
- If there is insufficient room in the pushback buffer, or if some other I/O error occurspublic 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.
cbuf
- Character array to push backIOException
- If there is insufficient room in the pushback buffer, or if some other I/O error occurspublic boolean ready() throws IOException
Tells whether this stream is ready to be read.
ready
in class FilterReader
IOException
- If an I/O error occurspublic void mark(int readAheadLimit) throws IOException
Marks the present position in the stream. The mark
for class PushbackReader
always throws an exception.
mark
in class FilterReader
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.IOException
- Always, since mark is not supportedpublic void reset() throws IOException
Resets the stream. The reset
method of PushbackReader
always throws an exception.
reset
in class FilterReader
IOException
- Always, since reset is not supportedpublic boolean markSupported()
Tells whether this stream supports the mark() operation, which it does not.
markSupported
in class FilterReader
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.
close
in interface Closeable
close
in interface AutoCloseable
close
in class FilterReader
IOException
- If an I/O error occurspublic 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.
skip
in class FilterReader
n
- The number of characters to skipIllegalArgumentException
- If n
is negative.IOException
- If an I/O error occurs
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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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