CODEWITHSUNDEEP
apache-commons-cli
Tad
Tad

Reputation: 838

Apache Commons CLI argument value

I am trying to write a program which when executed java -jar -cf file.txt will retrieve the value of the cf argument. The code I have so far is:

Options options = new Options();

final Option configFileOption = Option.builder("cf")
                        .longOpt("configfile")
                        .desc("Config file for Genome Store").argName("cf")
                        .build();

options.addOption(configFileOption);

CommandLineParser cmdLineParser = new DefaultParser();
CommandLine commandLineGlobal= cmdLineParser.parse(options, commandLineArguments);

if(commandLineGlobal.hasOption("cf")) {
        System.out.println(commandLineGlobal.getOptionValue("cf"));
    }

The problem I am facing is that the value which is being printed is null. Could anyone tell me what I am missing?

Upvotes: 2

Views: 4214

Answers (1)

centic
centic

Reputation: 15872

A useful method to find out why it does not work is to print out the help-information of commons-cli

    // automatically generate the help statement
    HelpFormatter formatter = new HelpFormatter();
    formatter.printHelp( "sample", options );

this prints

usage: sample
 -cf,--configfile   Config file for Genome Store

Which indicates that with longOpt() you are specifying an alias for the option, not the arg-value. The correct code to do what you want is:

    final Option configFileOption = Option.builder("cf")
                            .argName("configfile")
                            .hasArg()
                            .desc("Config file for Genome Store")
                            .build();

which correctly prints

usage: sample
 -cf <configfile>   Config file for Genome Store

and reports the passed argument to -cf correctly as well.

See the javadoc of the Option class for more details.

Upvotes: 6

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