Commons CLI API - Long Options

Q

How to manage long options with Apache Commons CLI API?

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A

A long option is a long keyword (multiple characters) option prefixed with "--". For example, "--help" is a long option.

A long option is supported in Apache Commons CLI API as an alias of a short option. For example, "--help" is an alias of "-h".

A long option can be managed with Apache Commons CLI API in 4 steps:

1. Define Options - A short option can be defined and added to the options collection by long the addOption() method with 4 arguments. For example:

import org.apache.commons.cli.Options;
      Options options = new Options();
      options.addOption("h", "help", false, "Print this help message");

2. Parse Options - A long option can be parsed together with all other options in a single call of CommandLineParser.parse(). For example:

import org.apache.commons.cli.CommandLineParser;
import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.DefaultParser;
         CommandLineParser parser = new DefaultParser();
         CommandLine cmd = parser.parse( options, args);

3. Process Options - A long option can be processed by calling the CommandLine.hasOption() method. For example:

         if (cmd.hasOption("help")) {
            help(options);
         }

4. Print Options - A long optoin can be printed out as help message together with all other options. For example:

import org.apache.commons.cli.HelpFormatter;
      HelpFormatter formatter = new HelpFormatter();
      formatter.printHelp("LongOptionTest", options);

 

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2018-11-10, 280👍, 0💬