java.io.PushbackReader Maven / Gradle / Ivy
/*
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stub files, must be accompanied by this notice in its entirety.
This work corresponds to the API signatures of JSR 219: Foundation
Profile 1.1. In the event of a discrepency between this work and the
JSR 219 specification, which is available at
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*/
package java.io;
/**
* A character-stream reader that allows characters to be pushed back into the
* stream.
*
* @version 1.14, 00/02/02
* @author Mark Reinhold
* @since JDK1.1
*/
public class PushbackReader extends FilterReader
{
/**
* Create a new pushback reader with a pushback buffer of the given size.
*
* @param in The reader from which characters will be read
* @param size The size of the pushback buffer
* @exception IllegalArgumentException if size is <= 0
*/
public PushbackReader(Reader in, int size) {
super(in);
}
/**
* Create a new pushback reader with a one-character pushback buffer.
*
* @param in The reader from which characters will be read
*/
public PushbackReader(Reader in) {
this(in, 1);
}
/**
* Read a single character.
*
* @return The character read, or -1 if the end of the stream has been
* reached
*
* @exception IOException If an I/O error occurs
*/
public int read() throws IOException {
return 0;
}
/**
* Read characters into a portion of an array.
*
* @param cbuf Destination buffer
* @param off Offset at which to start writing characters
* @param len Maximum number of characters to read
*
* @return The number of characters read, or -1 if the end of the
* stream has been reached
*
* @exception IOException If an I/O error occurs
*/
public int read(char[] cbuf, int off, int len) throws IOException {
return 0;
}
/**
* Push back a single character.
*
* @param c The character to push back
*
* @exception IOException If the pushback buffer is full,
* or if some other I/O error occurs
*/
public void unread(int c) throws IOException { }
/**
* Push 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.
*
* @param cbuf Character array
* @param off Offset of first character to push back
* @param len Number of characters to push back
*
* @exception IOException If there is insufficient room in the pushback
* buffer, or if some other I/O error occurs
*/
public void unread(char[] cbuf, int off, int len) throws IOException { }
/**
* Push 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.
*
* @param cbuf Character array to push back
*
* @exception IOException If there is insufficient room in the pushback
* buffer, or if some other I/O error occurs
*/
public void unread(char[] cbuf) throws IOException { }
/**
* Tell whether this stream is ready to be read.
*
* @exception IOException If an I/O error occurs
*/
public boolean ready() throws IOException {
return false;
}
/**
* Mark the present position in the stream. The mark
* for class PushbackReader always throws an exception.
*
* @exception IOException Always, since mark is not supported
*/
public void mark(int readAheadLimit) throws IOException { }
/**
* Reset the stream. The reset method of
* PushbackReader always throws an exception.
*
* @exception IOException Always, since reset is not supported
*/
public void reset() throws IOException { }
/**
* Tell whether this stream supports the mark() operation, which it does
* not.
*/
public boolean markSupported() {
return false;
}
/**
* Close the stream.
*
* @exception IOException If an I/O error occurs
*/
public void close() throws IOException { }
/**
* Skip characters. This method will block until some characters are
* available, an I/O error occurs, or the end of the stream is reached.
*
* @param n The number of characters to skip
*
* @return The number of characters actually skipped
*
* @exception IllegalArgumentException If n is negative.
* @exception IOException If an I/O error occurs
*/
public long skip(long n) throws IOException {
return -1;
}
}