help using pattern and matcher classes

Hi,

I have two words that I need to search my files for.

DONUMBER and DO_NUMBER.

I am not sure how I can create two patterns to search for in the same
file. Also what is the difference between the pattern and matcher (since
you can use regex in both).

This is the code I will use:

try {
            // Create the reader
            String filename = "infile.txt";
            String patternStr1 = "DONUMBER";
            String patternStr2 = "DO_NUMBER";
            BufferedReader rd = new BufferedReader(new FileReader(filename));

            // Create the pattern
            Pattern pattern = Pattern.compile();
            Matcher matcher = pattern.matcher("");

            // Retrieve all lines that match pattern
            String line = null;
            while ((line = rd.readLine()) != null) {
                matcher.reset(line);
                if (matcher.find()) {
                    // line matches the pattern
                }
            }
        } catch (IOException e) {
        }

All hints are very much welcome.

cheers,

//mikael