Package org.kohsuke.args4j

Annotation Type Option

  • @Retention(RUNTIME)
@Target({FIELD,METHOD,PARAMETER})
public @interface Option
    Marks a field/setter that receives a command line switch value.

    This annotation can be placed on a field of type T or the method of the form void methodName(T value). Its access modified can be anything, but if it's not public, your application needs to run in a security context that allows args4j to access the field/method (see AccessibleObject.setAccessible(boolean).

    The behavior of the annotation differs depending on T --- the type of the field or the parameter of the method.

    Boolean Switch

    When T is boolean , it represents a boolean option that takes the form of -OPT. When this option is set, the property will be set to true.

    String Switch

    When T is String, it represents an option that takes one operand. The value of the operand is set to the property.

    Enum Switch

    When T is derived from Enum, it represents an option that takes an operand, which must be one of the enum constant. The comparion between the operand and the enum constant name is done in a case insensitive fashion.

    For example, the following definition will represent command line options like -coin penny or -coin DIME, but things like -coin or -coin abc are errors. 

     enum Coin { PENNY,NICKEL,DIME,QUARTER }

 class Option {
   @Option(name="-coin")
   public Coin coin;
 }

    File Switch

    When T is a File, it represents an option that takes a file/directory name as an operand.

    Author:
    Kohsuke Kawaguchi

    • Required Element Summary

      Required Elements 
      Modifier and Type Required Element Description
      java.lang.String name
      Name of the option, such as -foo or -bar.

    • Optional Element Summary

      Optional Elements 
      Modifier and Type Optional Element Description
      java.lang.String[] aliases
      Aliases for the options, such as --long-option-name.
      java.lang.String[] depends
      List of other options that this option depends on.
      java.lang.String[] forbids
      List of other options that this option is incompatible with..
      java.lang.Class<? extends OptionHandler> handler
      Specify the OptionHandler that processes the command line arguments.
      boolean help
      Specify that the option is a help option.
      boolean hidden
      Specify that the option is hidden from the usage, by default.
      java.lang.String metaVar
      When the option takes an operand, the usage screen will show something like this
      boolean required
      Specify that the option is mandatory.
      java.lang.String usage
      Help string used to display the usage screen.

    • Element Detail

      • name

        java.lang.String name
        Name of the option, such as -foo or -bar.

      • aliases

        java.lang.String[] aliases
        Aliases for the options, such as --long-option-name.
        Default:
        {}

      • usage

        java.lang.String usage
        Help string used to display the usage screen.

        This parameter works in two ways. For a simple use, you can just encode the human-readable help string directly, and that will be used as the message. This is easier, but it doesn't support localization.

        For more advanced use, this property is set to a key of a ResourceBundle. The actual message is obtained by querying a ResourceBundle instance supplied to CmdLineParser by this key. This allows the usage screen to be properly localized.

        If this value is empty, the option will not be displayed in the usage screen.

        Default:
        ""

      • metaVar

        java.lang.String metaVar
        When the option takes an operand, the usage screen will show something like this 
         -x FOO  : blah blah blah
        You can replace the FOO token by using this parameter.

        If left unspecified, this value is infered from the type of the option.

        Just like usage(), normally, this value is printed as is. But if a ResourceBundle is given to the CmdLineParser, it will be used to obtain the locale-specific value.

        Default:
        ""

      • required

        boolean required
        Specify that the option is mandatory.

        At the end of CmdLineParser.parseArgument(String...), a CmdLineException will be thrown if a required option is not present.

        Note that in most of the command line interface design principles, options should be really optional. So use caution when using this flag.

        Default:
        false

      • help

        boolean help
        Specify that the option is a help option.

        When flagging an option being the help option, required arguments or options that are missing in an actual command line don't cause an exception to be thrown.

        See Also:
        required()
        Default:
        false

      • handler

        java.lang.Class<? extends OptionHandler> handler
        Specify the OptionHandler that processes the command line arguments.

        The default value OptionHandler indicates that the OptionHandler will be infered from the type of the field/method where a Option annotation is placed.

        If this annotation element is used, it overrides the inference and determines the handler to be used. This is convenient for defining a non-standard option parsing semantics.

        Example

         // this is a normal "-r" option
 @Option(name="-r")
 boolean value;

 // this causes arg4j to use MyHandler, not the default
 // handler provided for boolean
 @Option(name="-b",handler=MyHandler.class)
 boolean value;
        Default:
        org.kohsuke.args4j.spi.OptionHandler.class

      • depends

        java.lang.String[] depends
        List of other options that this option depends on.

        Example

          @Option(name="-a")
  int a;
  //-b is not required but if it's provided, then a becomes required
  @Option(name="-b", depends={"-a"})
  int b;

        At the end of CmdLineParser.parseArgument(String...), a CmdLineException will be thrown if options required by another one are not present.

        Default:
        {}

      • forbids

        java.lang.String[] forbids
        List of other options that this option is incompatible with..

        Example

          @Option(name="-a")
  int a;
  // -h and -a cannot be specified together
  @Option(name="-h", forbids={"-a"})
  boolean h;

        At the end of CmdLineParser.parseArgument(String...), a CmdLineException will be thrown if forbidden option combinations are present.

        Default:
        {}