Pattern Matching with Regular Expressions - Java - page 146

}

Pattern p = Pattern . compile ( args [ 0 ]);
for

for ( int int i = 1 ; i < args . length ; i ++)

process ( p , args [ i ]);

}

static static void void process ( Pattern pattern , String fileName ) throws throws IOException {

// Get a FileChannel from the given file.
FileChannel fc = new

new FileInputStream ( fileName ). getChannel ();

// Map the file's content
ByteBuffer buf = fc . map ( FileChannel . MapMode . READ_ONLY , 0 , fc . size ());

// Decode ByteBuffer into CharBuffer
CharBuffer cbuf =
Charset . forName ( "ISO-8859-1" ). newDecoder (). decode ( buf );

Matcher m = pattern . matcher ( cbuf );
while

while ( m . find ()) {
System . out . println ( m . group ( 0 ));

}

}

}

The NIO version shown in Example 4-5 relies on the fact that an NIO Buffer can be used as
a CharSequence . This program is more general in that the pattern argument is taken from the
command-line argument. It prints the same output as the previous example if invoked with
the pattern argument from the previous program on the command line:

java regex.GrepNIO "[A-Za-z][a-z]+" ReaderIter.java

You might think of using \w+ as the pattern; the only difference is that my pattern looks for
well-formed capitalized words, whereas \w+ would include Java-centric oddities like
theVariableName , which have capitals in nonstandard positions.

Also note that the NIO version will probably be more efficient because it doesn't reset the
Matcher to a new input source on each line of input as ReaderIter does.