The WeakMap class
WeakMap
&reftitle.intro;
A WeakMap is map (or dictionary) that accepts objects as keys. However, unlike the
otherwise similar SplObjectStorage, an object in a key of WeakMap
does not contribute toward the object's reference count. That is, if at any point the only remaining reference
to an object is the key of a WeakMap, the object will be garbage collected and removed
from the WeakMap. Its primary use case is for building caches of data derived from
an object that do not need to live longer than the object.
WeakMap implements ArrayAccess,
Traversable (via IteratorAggregate),
and Countable, so in most cases it can be used in the same fashion as an associative array.
&reftitle.classsynopsis;
final
WeakMap
implements
ArrayAccess
Countable
IteratorAggregate
&Methods;
&reftitle.examples;
<classname>Weakmap</classname> usage example
&example.outputs;
&language.predefined.weakmap.count;
&language.predefined.weakmap.getiterator;
&language.predefined.weakmap.offsetexists;
&language.predefined.weakmap.offsetget;
&language.predefined.weakmap.offsetset;
&language.predefined.weakmap.offsetunset;