class Flag[T] extends AnyRef

A single command-line flag, instantiated by a com.twitter.app.Flags instance.

The current value can be extracted via apply(), get, and getWithDefault. Local-scoped modifications of their values, which can be useful for tests, can be done by calls to let and letClear.

Using a String-typed Flag, myFlag, which is unset and has a default value of "DEFAULT" as an example:

myFlag.isDefined // => false
myFlag.get // => None
myFlag.getWithDefault // => Some("DEFAULT")
myFlag() // => "DEFAULT"

myFlag.let("a value") {
  myFlag.isDefined // => true
  myFlag.get // => Some("a value")
  myFlag.getWithDefault // => Some("a value")
  myFlag() // => "a value"

  myFlag.letClear {
    myFlag.isDefined // => false
    myFlag.get // => None
    myFlag.getWithDefault // => Some("DEFAULT")
    myFlag() // => "DEFAULT"
  }
}
See also

com.twitter.app.GlobalFlag

com.twitter.app.Flags for information on how flags can be set by the command line.

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Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##(): Int
    Definition Classes
    AnyRef → Any
  3. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  4. def apply(): T

    Return this flag's current value.

    Return this flag's current value. The default value is returned when the flag has not otherwise been set.

  5. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  6. def clone(): AnyRef
    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @native() @throws( ... )
  7. def defaultString(): String

    String representation of this flag's default value

  8. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  9. def equals(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  10. def finalize(): Unit
    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
  11. val flaggable: Flaggable[T]
    Attributes
    protected
  12. def get: Option[T]

    Get the value if it has been set.

    Get the value if it has been set.

    Note

    if no user-defined value has been set, None will be returned even when a default value is supplied.

    See also

    Flag.getWithDefault

  13. final def getClass(): Class[_]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  14. def getValue: Option[T]
    Attributes
    protected
  15. def getWithDefault: Option[T]

    Get the value if it has been set or if there is a default value supplied.

    Get the value if it has been set or if there is a default value supplied.

    See also

    Flag.get and Flag.isDefined if you are interested in determining if there is a supplied value.

  16. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  17. val help: String
  18. def isDefined: Boolean

    True if the flag has been set.

    True if the flag has been set.

    Note

    if no user-defined value has been set, false will be returned even when a default value is supplied.

  19. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  20. def let[R](t: T)(f: ⇒ R): R

    Override the value of this flag with t, only for the scope of the current com.twitter.util.Local for the given function f.

    Override the value of this flag with t, only for the scope of the current com.twitter.util.Local for the given function f.

    See also

    letClear

  21. def letClear[R](f: ⇒ R): R

    Unset the value of this flag, such that isDefined will return false, only for the scope of the current com.twitter.util.Local for the given function f.

    Unset the value of this flag, such that isDefined will return false, only for the scope of the current com.twitter.util.Local for the given function f.

    See also

    let

  22. val name: String
  23. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  24. def noArgumentOk: Boolean

    Indicates whether or not the flag is valid without an argument.

  25. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  26. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  27. def parse(): Unit

    Parse this flag with no argument.

  28. def parse(raw: String): Unit

    Parse value raw into this flag.

  29. def parsingDone: Boolean
    Attributes
    protected[this]
  30. def reset(): Unit

    Reset this flag's value

  31. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
    AnyRef
  32. def toString(): String

    String representation of this flag in -foo='bar' format, suitable for being used on the command line.

    String representation of this flag in -foo='bar' format, suitable for being used on the command line.

    Definition Classes
    Flag → AnyRef → Any
  33. def usageString: String
  34. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  35. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  36. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @native() @throws( ... )

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