org.neo4j.unsafe.impl.internal.dragons

Class FeatureToggles

java.lang.Object

org.neo4j.unsafe.impl.internal.dragons.FeatureToggles

public class FeatureToggles
extends Object

Feature toggles are used for features that are possible to configure, but where the configuration is always fixed in a production system. Typical use cases for feature toggles are features that are integrated into the code base for integration and testing purposes, but are not ready for inclusion in the finished product yet, or features that are always on or has a fixed configured value in the finished product, but can assume a different configuration or be turned off in some test. Feature toggles are passed to the JVM through system properties, and expected to be looked up from a static context, a static final fields of the class the toggle controls. All methods in this class returns the default value if the system property has not been assigned, or if the value of the system property cannot be interpreted as a value of the expected type. For features that the user is ever expected to touch, feature toggles is the wrong abstraction!

Method Summary

Modifier and Type	Method and Description
static void	clear(Class<?> location, String name) Clear the value of a system property.
static boolean	flag(Class<?> location, String name, boolean defaultValue) Get the value of a boolean system property.
static <E extends Enum<E>> E	flag(Class<?> location, String name, E defaultValue) Get the value of a enum system property.
static double	getDouble(Class<?> location, String name, double defaultValue) Get the value of a double system property.
static int	getInteger(Class<?> location, String name, int defaultValue) Get the value of a int system property.
static long	getLong(Class<?> location, String name, long defaultValue) Get the value of a long system property.
static String	getString(Class<?> location, String name, String defaultValue) Get the value of a String system property.
static boolean	packageFlag(Class<?> location, String name, boolean defaultValue) Get the value of a boolean system property.
static void	set(Class<?> location, String name, Object value) Set the value of a system property.
static String	toggle(Class<?> location, String name, Object value) Helps creating a JVM parameter for setting a feature toggle of an arbitrary type.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

flag

public static boolean flag(Class<?> location,
                           String name,
                           boolean defaultValue)

Get the value of a boolean system property. The absolute name of the system property is computed based on the provided class and local name.

Parameters:

location - the class that owns the flag.

name - the local name of the flag.

defaultValue - the default value of the flag if the system property is not assigned.

Returns:

the parsed value of the system property, or the default value.

packageFlag

public static boolean packageFlag(Class<?> location,
                                  String name,
                                  boolean defaultValue)

Get the value of a boolean system property. The absolute name of the system property is computed based on the package of the provided class and local name.

Parameters:

location - a class in the package that owns the flag.

name - the local name of the flag.

defaultValue - the default value of the flag if the system property is not assigned.

Returns:

the parsed value of the system property, or the default value.

getLong

public static long getLong(Class<?> location,
                           String name,
                           long defaultValue)

Get the value of a long system property. The absolute name of the system property is computed based on the provided class and local name.

Parameters:

location - the class that owns the flag.

name - the local name of the flag.

defaultValue - the default value of the flag if the system property is not assigned.

Returns:

the parsed value of the system property, or the default value.

getInteger

public static int getInteger(Class<?> location,
                             String name,
                             int defaultValue)

Get the value of a int system property. The absolute name of the system property is computed based on the provided class and local name.

Parameters:

location - the class that owns the flag.

name - the local name of the flag.

defaultValue - the default value of the flag if the system property is not assigned.

Returns:

the parsed value of the system property, or the default value.

getDouble

public static double getDouble(Class<?> location,
                               String name,
                               double defaultValue)

Get the value of a double system property. The absolute name of the system property is computed based on the provided class and local name.

Parameters:

location - the class that owns the flag.

name - the local name of the flag

defaultValue - the default value of the flag if the system property is not assigned.

Returns:

the parsed value of the system property, or the default value.

getString

public static String getString(Class<?> location,
                               String name,
                               String defaultValue)

Get the value of a String system property.

The absolute name of the system property is computed based on the provided class and local name.

Parameters:

location - the class that owns the flag.

name - the local name of the flag

defaultValue - the default value of the flag if the system property is not assigned.

Returns:

the parsed value of the system property, or the default value.

flag

public static <E extends Enum<E>> E flag(Class<?> location,
                                         String name,
                                         E defaultValue)

Get the value of a enum system property. The absolute name of the system property is computed based on the provided class and local name.

Type Parameters:

E - the enum value type.

Parameters:

location - the class that owns the flag.

name - the local name of the flag.

defaultValue - the default value of the flag if the system property is not assigned.

Returns:

the parsed value of the system property, or the default value.

set

public static void set(Class<?> location,
                       String name,
                       Object value)

Set the value of a system property.

The name of the system property is computed based on the provided class and local name.

Parameters:

location - the class that owns the flag.

name - the local name of the flag.

value - the value to assign to the system property.

clear

public static void clear(Class<?> location,
                         String name)

Clear the value of a system property.

The name of the system property is computed based on the provided class and local name.

Parameters:

location - the class that owns the flag.

name - the local name of the flag.

toggle

public static String toggle(Class<?> location,
                            String name,
                            Object value)

Helps creating a JVM parameter for setting a feature toggle of an arbitrary type. Given value will be converted to string using Objects.toString(Object) method.

Parameters:

location - the class that owns the flag.

name - the local name of the flag.

value - the value to assign to the feature toggle.

Returns:

the parameter to pass to the command line of the forked JVM.