GlobalFlag

Subclasses of GlobalFlag (that are defined in libraries) are "global" in the sense that they are accessible by any application that depends on that library. Regardless of where in a library a GlobalFlag is defined, a value for it can be passed as a command-line flag by any binary that includes the library. The set of defined GlobalFlags can be enumerated (via GlobalFlag.getAll) by the application.

A GlobalFlag must be declared as an object (see below for Java):

import com.twitter.app.GlobalFlag

object myFlag extends GlobalFlag[String]("default value", "this is my global flag")

All such global flag declarations in a given classpath are visible to and used by com.twitter.app.App.

A flag's name (as set on the command line) is its fully-qualified classname. For example, the flag

package com.twitter.server

import com.twitter.app.GlobalFlag

object port extends GlobalFlag[Int](8080, "the TCP port to which we bind")

is settable by the command-line flag -com.twitter.server.port=8080.

Global flags may also be set by Java system properties with keys named in the same way. However, values supplied by flags override those supplied by system properties.

Annotations: @GlobalFlagVisible()

Linear Supertypes

Flag[T], AnyRef, Any

Known Subclasses

JavaGlobalFlag, loadServiceDenied, loadServiceIgnoredPaths

Instance Constructors

new GlobalFlag(help: String)(implicit _f: Flaggable[T], m: Manifest[T])

_declaration
_declaration
If you'd like to declare a new GlobalFlag in Java, see JavaGlobalFlag._declaration
help
documentation regarding usage of this Flag.
new GlobalFlag(default: T, help: String)(implicit _f: Flaggable[T])

_declaration
_declaration
If you'd like to declare a new GlobalFlag in Java, see JavaGlobalFlag._declaration
default
the default value used if the value is not specified by the user.
help
documentation regarding usage of this Flag.

Value Members

final def !=(arg0: Any): Boolean

Definition Classes
AnyRef → Any
final def ##(): Int

Definition Classes
AnyRef → Any
final def ==(arg0: Any): Boolean

Definition Classes
AnyRef → Any
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.

Definition Classes
Flag
final def asInstanceOf[T0]: T0

Definition Classes
Any
def clone(): AnyRef

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( ... )
def defaultString(): String

String representation of this flag's default value
String representation of this flag's default value

Definition Classes
Flag
final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef
def equals(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def finalize(): Unit

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
val flaggable: Flaggable[T]

Attributes
protected
Definition Classes
Flag
def get: Option[T]

Get the value if it has been set.
Get the value if it has been set.

Definition Classes
Flag
Note
if no user-defined value has been set, None will be returned even when a default value is supplied.
See also
Flag.getWithDefault
final def getClass(): Class[_]

Definition Classes
AnyRef → Any
def getGlobalFlag: Flag[_]

Used by Flags.parseArgs to initialize Flag values.
Used by Flags.parseArgs to initialize Flag values.

Note
Called via reflection assuming it will be a static method on a singleton object. This causes problems for Java developers who want to create a GlobalFlag as there is no good means for them to have it be a static method. Thus, Java devs must add a method public static Flag<?> globalFlagInstance() which returns the singleton instance of the flag. See JavaGlobalFlag for more details.
def getValue: Option[T]

Attributes
protected
Definition Classes
GlobalFlag → Flag
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.

Definition Classes
Flag
See also
Flag.get and Flag.isDefined if you are interested in determining if there is a supplied value.
def hashCode(): Int

Definition Classes
AnyRef → Any
val help: String

Definition Classes
Flag
def isDefined: Boolean

True if the flag has been set.
True if the flag has been set.

Definition Classes
Flag
Note
if no user-defined value has been set, false will be returned even when a default value is supplied.
final def isInstanceOf[T0]: Boolean

Definition Classes
Any
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.

Definition Classes
Flag
See also
letClear
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.

Definition Classes
Flag
See also
let
val name: String

The "name", or "id", of this Flag.
The "name", or "id", of this Flag.
While not marked final, if a subclass overrides this value, then developers must set that flag via System properties as otherwise it will not be recognized with command-line arguments. e.g. -DyourGlobalFlagName=flagName

Definition Classes
GlobalFlag → Flag
final def ne(arg0: AnyRef): Boolean

Definition Classes
AnyRef
def noArgumentOk: Boolean

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

Definition Classes
Flag
final def notify(): Unit

Definition Classes
AnyRef
final def notifyAll(): Unit

Definition Classes
AnyRef
def parse(): Unit

Parse this flag with no argument.
Parse this flag with no argument.

Definition Classes
Flag
def parse(raw: String): Unit

Parse value raw into this flag.
Parse value raw into this flag.

Definition Classes
Flag
def parsingDone: Boolean

Attributes
protected[this]
Definition Classes
GlobalFlag → Flag
def reset(): Unit

Reset this flag's value
Reset this flag's value

Definition Classes
Flag
final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef
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
def usageString: String

Definition Classes
Flag
final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long, arg1: Int): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )

Related Docs: object GlobalFlag | package app

abstract class GlobalFlag[T] extends Flag[T]

Instance Constructors

new GlobalFlag(help: String)(implicit _f: Flaggable[T], m: Manifest[T])

new GlobalFlag(default: T, help: String)(implicit _f: Flaggable[T])

Value Members

final def !=(arg0: Any): Boolean

final def ##(): Int

final def ==(arg0: Any): Boolean

def apply(): T

final def asInstanceOf[T0]: T0

def clone(): AnyRef

def defaultString(): String

final def eq(arg0: AnyRef): Boolean

def equals(arg0: Any): Boolean

def finalize(): Unit

val flaggable: Flaggable[T]

def get: Option[T]

final def getClass(): Class[_]

def getGlobalFlag: Flag[_]

def getValue: Option[T]

def getWithDefault: Option[T]

def hashCode(): Int

val help: String

def isDefined: Boolean

final def isInstanceOf[T0]: Boolean

def let[R](t: T)(f: ⇒ R): R

def letClear[R](f: ⇒ R): R

val name: String

final def ne(arg0: AnyRef): Boolean

def noArgumentOk: Boolean

final def notify(): Unit

final def notifyAll(): Unit

def parse(): Unit

def parse(raw: String): Unit

def parsingDone: Boolean

def reset(): Unit

final def synchronized[T0](arg0: ⇒ T0): T0

def toString(): String

def usageString: String

final def wait(): Unit

final def wait(arg0: Long, arg1: Int): Unit

final def wait(arg0: Long): Unit

Inherited from Flag[T]

Inherited from AnyRef

Inherited from Any

Ungrouped