Using Jakarta Commons CLI

Several examples from Jakarta Commons Cookbook by Timothy M. O’Brien, O’Reilly, Nov 2004

Example 1: Parsing a Simple Command Line

import org.apache.commons.cli.CommandLineParser;
import org.apache.commons.cli.BasicParser;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.CommandLine;

public static void main(String[] args) throws Exception {

    // Create a Parser
    CommandLineParser parser = new BasicParser( );
    Options options = new Options( );
    options.addOption(”h”, “help”, false, “Print this usage information”);
    options.addOption(”v”, “verbose”, false, “Print out VERBOSE information” );
    options.addOption(”f”, “file”, true, “File to save program output to”);

    // Parse the program arguments
    CommandLine commandLine = parser.parse( options, args );

    // Set the appropriate variables based on supplied options
    boolean verbose = false;
    String file = “”;

    if( commandLine.hasOption(’h') ) {
        System.out.println( “Help Message”)
        System.exit(0);
    }

    if( commandLine.hasOption(’v') ) {
        verbose = true;
    }

    if( commandLine.hasOption(’f') ) {
        file = commandLine.getOptionValue(’f');
    }
}

Example 2: Using OptionGroup

import org.apache.commons.cli.CommandLineParser;
import org.apache.commons.cli.BasicParser;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.OptionBuilder;
import org.apache.commons.cli.OptionGroup;
import org.apache.commons.cli.CommandLine;

public static void main(String[] args) throws Exception {

    // Create a Parser
    CommandLineParser parser = new BasicParser( );
    Options options = new Options( );
    options.addOption(”h”, “help”, false, “Print this usage information”);
    options.addOption(”v”, “verbose”, false, “Print out VERBOSE information” );

    OptionGroup optionGroup = new OptionGroup( );
    optionGroup.addOption( OptionBuilder.hasArg(true).create(’f') );
    optionGroup.addOption( OptionBuilder.hasArg(true).create(’m') );
    options.addOptionGroup( optionGroup );

    // Parse the program arguments
    CommandLine commandLine = parser.parse( options, args );

    // … do important stuff …
}

Example 3: Print Usage Info

import org.apache.commons.cli.CommandLineParser;
import org.apache.commons.cli.BasicParser;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.OptionBuilder;
import org.apache.commons.cli.OptionGroup;
import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.HelpFormatter;

public class SomeApp {
    private static final String USAGE = “[-h] [-v] [-f <file> | -m <email>]”;
    private static final String HEADER =
        “SomeApp - A fancy and expensive program, Copyright 2010 Blah.”;
    private static final String FOOTER =
        “For more instructions, see our website at: http://www.blah123.org”;

    public static void main(String[] args) throws Exception {

        // Create a Parser
        CommandLineParser parser = new BasicParser( );
        Options options = new Options( );
        options.addOption(”h”, “help”, false, “Print this usage
                                                                      information”);
        options.addOption(”v”, “verbose”, false, “Print out VERBOSE
                                                                         information” );

        OptionGroup optionGroup = new OptionGroup( );
        optionGroup.addOption( OptionBuilder.hasArg(true).withArgName(”file”)
                                            .withLongOpt(”file”).create(’f') );
        optionGroup.addOption( OptionBuilder.hasArg(true).withArgName(”email”)
                                            .withLongOpt(”email”).create(’m') );
        options.addOptionGroup( optionGroup );
           // Parse the program arguments
        try {
            CommandLine commandLine = parser.parse( options, args );

            if( commandLine.hasOption(’h') ) {
                printUsage( options );
                System.exit(0);
            }
   
               // … do important stuff …
        } catch( Exception e ) {
            System.out.println( “You provided bad program arguments!” );
            printUsage( options );
            System.exit(1);
        }
    }

    private static void printUsage(Options options) {
        HelpFormatter helpFormatter = new HelpFormatter( );
        helpFormatter.setWidth( 80 );
        helpFormatter.printHelp( USAGE, HEADER, options, FOOTER );
    }
}