Package arez.spy

Enum Class Priority

java.lang.Object

java.lang.Enum<Priority>

arez.spy.Priority

All Implemented Interfaces:

Serializable, Comparable<Priority>, Constable

public enum Priority
extends Enum<Priority>

Enum to control scheduling priority of observers/reactions. Observers with higher priorities will react first. If observers have equal priorities then observers scheduled first will react first. Observers must not depend upon ComputableValue instances with a lower priority otherwise priority is ignored.

A user should be very careful when specifying a HIGH priority as it is possible that the the reaction will be scheduled part way through the process of disposing and/or unlinking one-or-more components. Dispose reactions will often be scheduled with a higher priority but reactions unlinking disposed arez components from remaining arez components. In many cases this may mean invoking Disposable.isDisposed(Object) before accessing arez components.

See Also:

• Priority

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Enum

Enum.EnumDesc<E extends Enum<E>>

Enum Constant Summary

Enum Constants

Enum Constant	Description
HIGH	High priority.
HIGHEST	Highest priority.
LOW	Low priority.
LOWEST	Lowest priority.
NORMAL	Normal priority if not otherwise specified.

Method Summary

Modifier and Type	Method	Description
static Priority	valueOf(String name)	Returns the enum constant of this class with the specified name.
static Priority[]	values()	Returns an array containing the constants of this enum class, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, describeConstable, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Details

HIGHEST

public static final Priority HIGHEST

Highest priority. This priority should be used when the reaction will dispose other reactive elements (and thus they need not be scheduled).

HIGH

public static final Priority HIGH

High priority. This priority should be used when the reaction will trigger many downstream reactions.

NORMAL

public static final Priority NORMAL

Normal priority if not otherwise specified.

LOW

public static final Priority LOW

Low priority. Usually used to schedule observers that reflect state onto non-reactive application components. i.e. Observers that are used to build html views, perform network operations etc. These reactions are often at low priority to avoid recalculation of dependencies (i.e. ComputableValues) triggering this reaction multiple times within a single reaction round.

LOWEST

public static final Priority LOWEST

Lowest priority. This is low-priority reactions that reflect onto non-reactive applications. It is also used for (i.e. ComputableValues) that may be unobserved when a LOW priority reaction runs.

Method Details

values

public static Priority[] values()

Returns an array containing the constants of this enum class, in the order they are declared.

Returns:

an array containing the constants of this enum class, in the order they are declared

valueOf

public static Priority valueOf(String name)

Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum class has no constant with the specified name

NullPointerException - if the argument is null