default:
if (!marked)
System.out.print((char) c);
break;
}
}
}
}
BufferedWriter
A BufferedWriter is a Writer that buffers ouput. Using a BufferedWriter can increase
performance by reducing the number of times data is actually physically written to the
output stream.
A BufferedWriter has these two constructors:
BufferedWriter(Writer outputStream)
BufferedWriter(Writer outputStream, int bufSize)
The first form creates a buffered stream using a buffer with a default size. In the second, the
size of the buffer is passed in bufSize.
PushbackReader
The PushbackReader class allows one or more characters to be returned to the input stream.
This allows you to look ahead in the input stream. Here are its two constructors:
PushbackReader(Reader inputStream)
PushbackReader(Reader inputStream, int bufSize)
The first form creates a buffered stream that allows one character to be pushed back. In the
second, the size of the pushback buffer is passed in bufSize.
PushbackReader provides unread( ), which returns one or more characters to the invoking
input stream. It has the three forms shown here:
void unread(int ch)
void unread(char buffer[ ])
void unread(char buffer[ ], int offset, int numChars)
The first form pushes back the character passed in ch. This will be the next character returned
by a subsequent call to read( ). The second form returns the characters in buffer. The third
form pushes back numChars characters beginning at offset from buffer. An IOException will
be thrown if there is an attempt to return a character when the pushback buffer is full.
The following program reworks the earlier PushBackInputStream example by replacing
PushBackInputStream with a PushbackReader. As before, it shows how a programming
language parser can use a pushback stream to deal with the difference between the == operator
for comparison and the = operator for assignment.
// Demonstrate unread().
import java.io.*;
class PushbackReaderDemo {
public static void main(String args[]) throws IOException {
String s = "if (a == 4) a = 0;\n";
Search WWH :
