Parsing arguments to a Java command line program

Question

What if I wanted to parse this:

java MyProgram -r opt1 -S opt2 arg1 arg2 arg3 arg4 --test -A opt3

And the result I want in my program is:

Answer 1

You could use https://github.com/jankroken/commandline , here's how to do that:

To make this example work, I must make assumptions about what the arguments means - just picking something here...

-r opt1 => replyAddress=opt1
-S opt2 arg1 arg2 arg3 arg4 => subjects=[opt2,arg1,arg2,arg3,arg4]
--test = test=true (default false)
-A opt3 => address=opt3

this can then be set up this way:

public class MyProgramOptions {
  private String replyAddress;
  private String address;
  private List subjects;
  private boolean test = false;

  @ShortSwitch("r")
  @LongSwitch("replyAddress") // if you also want a long variant. This can be skipped
  @SingleArgument
  public void setReplyAddress(String replyAddress) {
    this.replyAddress = replyAddress;
  }

  @ShortSwitch("S")
  @AllAvailableArguments
  public void setSubjects(List subjects) {
    this.subjects = subjects;
  }

  @LongSwitch("test")
  @Toggle(true)
  public void setTest(boolean test) {
    this.test = test;
  }

  @ShortSwitch("A")
  @SingleArgument
  public void setAddress(String address) {
    this.address = address;
  }

  // getters...
}

and then in the main method, you can just do:

public final static void main(String[] args) {
  try {
    MyProgramOptions options = CommandLineParser.parse(MyProgramOptions.class, args, OptionStyle.SIMPLE);

    // and then you can pass options to your application logic...

  } catch
    ...
  }
}