Apache Commons CLI - option type and default value

I do not know if not working or if added recently but getOptionValue() has an overloaded version that accepts a default (String) value

EDIT: Default values are now supported. See answer https://stackoverflow.com/a/14309108/1082541 below.

As Brent Worden already mentioned, default values are not supported.

I had issues with using Option.setType too. I always got a null pointer exception when calling getParsedOptionValue on an option with type Integer.class. Because the documentation was not really helpful I looked into the source code.

Looking at the TypeHandler class and the PatternOptionBuilder class you can see that Number.class must be used for int or Integer.

And here is a simple example:

CommandLineParser cmdLineParser = new PosixParser();

Options options = new Options();
options.addOption(OptionBuilder.withLongOpt("integer-option")
                      .withDescription("description")
                      .withType(Number.class)
                      .hasArg()
                      .withArgName("argname")
                      .create());

try {
    CommandLine cmdLine = cmdLineParser.parse(options, args);

    int value = 0; // initialize to some meaningful default value
    if (cmdLine.hasOption("integer-option")) {
        value = ((Number)cmdLine.getParsedOptionValue("integer-option")).intValue();
    }

    System.out.println(value);
} catch (ParseException e) {
    e.printStackTrace();
}

Keep in mind that value can overflow if a number is provided which does not fit into an int.

The OptionBuilder is deprecated in version 1.3 & 1.4 and Option.Builder doesn't seem to have a direct function to set the type. There is a function for the Option class called setType. You can a retrieve a converted value with the function CommandLine.getParsedOptionValue. Not sure why it's not part of the builder anymore. It requires some code like this now:

    options = new Options();

    Option minOpt = Option.builder("min").hasArg().build();
    minOpt.setType(Number.class);
    options.addOption(minOpt);

and reading it:

    String testInput = "-min 14";
    String[] splitInput = testInput.split("\\s+");

    CommandLine cmd =  CLparser.parse(options, splitInput);
    System.out.println(cmd.getParsedOptionValue("min")); 

which would give a variable of type Long