Package nz.org.riskscape.picocli

Annotation Interface CommandLine.Mixin

Enclosing class:
CommandLine
@Retention(RUNTIME) @Target({FIELD,PARAMETER}) public static @interface CommandLine.Mixin

Fields annotated with @Mixin are "expanded" into the current command: @Option and @Parameters in the mixin class are added to the options and positional parameters of this command. A CommandLine.DuplicateOptionAnnotationsException is thrown if any of the options in the mixin has the same name as an option in this command.

The Mixin annotation provides a way to reuse common options and parameters without subclassing. For example: 

  class HelloWorld implements Runnable {

 
 
 // adds the --help and --version options to this command
  @Mixin
  private HelpOptions = new HelpOptions();
 
  @Option(names = {"-u", "--userName"}, required = true, description = "The user name")
  String userName;
 
  public void run() { System.out.println("Hello, " + userName); }
 

 
 
}

 
 
// Common reusable help options.
  class HelpOptions {

 
 
 @Option(names = { "-h", "--help"}, usageHelp = true, description = "Display this help and exit")
  private boolean help;
 
  @Option(names = { "-V", "--version"}, versionHelp = true, description = "Display version info and exit")
  private boolean versionHelp;
 

 
 
}

Since:
3.0

  • Optional Element Summary

    Optional Elements
    Modifier and Type
    Optional Element
    Description
    String
    name
    Optionally specify a name that the mixin object can be retrieved with from the CommandSpec.

  • Element Details

    • name

      String name
      Optionally specify a name that the mixin object can be retrieved with from the CommandSpec. If not specified the name of the annotated field is used.
      Returns:
      a String to register the mixin object with, or an empty String if the name of the annotated field should be used
      Default:
      ""