com.koloboke.compile

Annotation Type NullKeyAllowed

@Retention(value=SOURCE)
 @Target(value=TYPE)
public @interface NullKeyAllowed

Specifies whether a Koloboke Compile-generated implementation of the annotated Set- or Map-like class or interface with a reference key type should allow insertion and queries of the null key. If a @KolobokeSet- or @KolobokeMap-annotated type is not annotated with @NullKeyAllowed or annotated with @NullKeyAllowed(false), Koloboke Compile generates an implementation that throws NullPointerException on any attempt to insert or query the presence of the null key in the instance of this implementation. If the implemented type is annotated with @NullKeyAllowed or NullKeyAllowed(true), Koloboke Compile generates an implementation that fully allows the null key (just like HashSet or HashMap).

The Koloboke Collections's API counterpart of @NullKeyAllowed is ObjHashFactory.withNullKeyAllowed(boolean) configuration. An important difference is that @NullKeyAllowed does guarantee that the implementation, generated by Koloboke Compile, throws NullPointerException to enforce the null key disallowance in runtime, while ObjHashFactory doesn't guarantee that.

If the annotated type has a numeric primitive key type, Koloboke Compile emits a compilation error and doesn't generate an implementation for the annotated type.

See Also:

Key nullability section in the @KolobokeMap specification, Key nullability section in the @KolobokeSet specification

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
boolean	value Tells whether a Koloboke Compile-generated implementation of the annotated Set- or Map-like class or interface should allow insertion and queries of the null key.

Element Detail

value

public abstract boolean value

Tells whether a Koloboke Compile-generated implementation of the annotated Set- or Map-like class or interface should allow insertion and queries of the null key.

Default value is true, that allows natural omission of the value specification: @NullKeyAllowed is equivalent to @NullKeyAllowed(true) or @NullKeyAllowed(value=true), but @NullKeyAllowed is not applied to a class or interface altogether, Koloboke Compile generates an implementation that disallow the null key.

Returns:

true if the Koloboke Compile-generated implementation of the annotated type should allow insertion and queries of the null key, false otherwise

Default:

true