Module info.picocli

Package picocli

Annotation Type CommandLine.Mixin

@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:

 @Command(name="HelloWorld")
 class HelloWorld implements Runnable {

     // adds the --help and --version options to this command
     @Mixin
     private HelpOptions options = 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 Detail

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:

""