Abstract supertype of objects which associate values with keys.

Correspondence does not satisfy Category, since in some cases—List, for example—it is convenient to consider the subtype a Category of its indexed items, and in other cases—Map, for example—it is convenient to treat the subtype as a Category of its entries.

The item corresponding to a given key may be obtained from a Correspondence using the item operator:

value bg = settings["backgroundColor"] else white;

The get() operation and item operator result in an optional type, to reflect the possibility that there may be no item for the given key.

By: Gavin
See also Map, List, Category

no type hierarchy

no supertypes hierarchy

Attributes
keysSource Codeshared default Category<Key> keys

The Category of all keys for which a value is defined by this Correspondence.

See also defines()
Inherited Attributes
Attributes inherited from: Object
Methods
definesSource Codeshared formal Boolean defines(Key key)

Determines if there is a value defined for the given key.

definesAnySource Codeshared default Boolean definesAny({Key*} keys)

Determines if this Correspondence defines a value for any one of the given keys.

See also defines()
definesEverySource Codeshared default Boolean definesEvery({Key*} keys)

Determines if this Correspondence defines a value for every one of the given keys.

See also defines()
getSource Codeshared formal Item? get(Key key)

Returns the value defined for the given key, or null if there is no value defined for the given key.

See also getAll()
getAllSource Codeshared default Iterable<Item?,Absent> getAll<Absent>(Iterable<Key,Absent> keys)
given Absent satisfies Null

Returns the items defined for the given keys, in the same order as the corresponding keys. For any key which does not have an item defined, the resulting stream contains the value null.

See also get()
Inherited Methods
Methods inherited from: Object