Module info.picocli
Package picocli

Interface CommandLine.IParameterConsumer

  • Enclosing class:

    public static interface CommandLine.IParameterConsumer
    Options or positional parameters can be assigned a IParameterConsumer that implements custom logic to process the parameters for this option or this position. When an option or positional parameter with a custom IParameterConsumer is matched on the command line, picocli's internal parser is temporarily suspended, and this object becomes responsible for consuming and processing as many command line arguments as needed.

    This may be useful when passing through parameters to another command.

    Example usage:

     @Command(name = "find")
     class Find {
         @Option(names = "-exec", parameterConsumer = Find.ExecParameterConsumer.class)
         List<String> list = new ArrayList<String>();
         static class ExecParameterConsumer implements IParameterConsumer {
             public void consumeParameters(Stack<String> args, ArgSpec argSpec, CommandSpec commandSpec) {
                 List<String> list = argSpec.getValue();
                 while (!args.isEmpty()) {
                     String arg = args.pop();
                     // `find -exec` semantics: stop processing after a ';' or '+' argument
                     if (";".equals(arg) || "+".equals(arg)) {

    If this interface does not meet your requirements, you may have a look at the more powerful and flexible CommandLine.IParameterPreprocessor interface introduced with picocli 4.6.

    See Also:
    CommandLine.Option.parameterConsumer(), CommandLine.Parameters.parameterConsumer()
    • Method Detail

      • consumeParameters

        void consumeParameters​(Stack<String> args,
                               CommandLine.Model.ArgSpec argSpec,
                               CommandLine.Model.CommandSpec commandSpec)
        Consumes as many of the specified command line arguments as needed by popping them off the specified Stack. Implementors are free to ignore the arity of the option or positional parameter, they are free to consume arguments that would normally be matched as other options of the command, and they are free to consume arguments that would normally be matched as an end-of-options delimiter.

        Implementors are responsible for saving the consumed values; if the user object of the option or positional parameter is a Collection or a Map, a common approach would be to obtain the current instance via the CommandLine.Model.ArgSpec.getValue(), and add to this instance. If the user object is an array, the implementation would need to create a new array that contains the old values as well as the newly consumed values, and store this array in the user object via the CommandLine.Model.ArgSpec.setValue(Object).

        If the user input is invalid, implementations should throw a CommandLine.ParameterException with a message to display to the user.

        When this method returns, the picocli parser will process the remaining arguments on the Stack.

        args - the command line arguments
        argSpec - the option or positional parameter for which to consume command line arguments
        commandSpec - the command that the option or positional parameter belongs to
        CommandLine.ParameterException - if the user input is invalid