Java The Complete Reference, Seventh Edition

586 Part II: The Java Library

char buf[] = new char[s.length()];

s.getChars(0, s.length(), buf, 0);

CharArrayReader in = new CharArrayReader(buf);

PushbackReader f = new PushbackReader(in);

int c;

while ((c = f.read()) != -1) {

switch(c) {

case '=':

if ((c = f.read()) == '=')

System.out.print(".eq.");

else {

System.out.print("<-");

f.unread(c);

}

break;

default:

System.out.print((char) c);

break;

}

}

}

}

PrintWriter

PrintWriteris essentially a character-oriented version ofPrintStream. It implements the

Appendable,Closeable, andFlushableinterfaces.PrintWriterhas several constructors.

The following have been supplied byPrintWriterfrom the start:

PrintWriter(OutputStreamoutputStream)

PrintWriter(OutputStreamoutputStream, booleanflushOnNewline)

PrintWriter(WriteroutputStream)

PrintWriter(WriteroutputStream, booleanflushOnNewline)

Here,outputStreamspecifies an openOutputStreamthat will receive output. TheflushOnNewline

parameter controls whether the output buffer is automatically flushed every timeprintln( ),

printf( ),orformat( )is called. IfflushOnNewlineistrue, flushing automatically takes place. If

false, flushing is notautomatic. Constructors that do not specify theflushOnNewlineparameter

do not automatically flush.

The next set of constructors give you an easy way to construct aPrintWriterthat writes its

output to a file.

PrintWriter(FileoutputFile) throws FileNotFoundException

PrintWriter(FileoutputFile, StringcharSet)

throws FileNotFoundException, UnsupportedEncodingException

PrintWriter(StringoutputFileName) throws FileNotFoundException

PrintWriter(StringoutputFileName, StringcharSet)

throws FileNotFoundException, UnsupportedEncodingException