invoker method Null safety
- String memberName
Returns an invoker builder for the given
memberName. An invoker builder
is a closure that takes an object and returns an invoker for that object.
The returned invoker is a closure that invokes the
memberName on the
object it is specialized for. In other words, the invoker-builder returns
a tear-off of
memberName for any given object that implements the
class this ClassMirror reflects on.
Example: var invokerBuilder = classMirror.invoker("foo"); var invoker = invokerBuilder(o); invoker(42); // Equivalent to o.foo(42).
More precisely, let c be the returned closure, let f be the simple
name of the member denoted by
memberName, and let o be an instance
of the class reflected by this mirror. Consider the following invocation:
c(o)(a1, ..., an, k1: v1, ..., km: vm)
This invocation corresponds to the following non-reflective invocation:
o.f(a1, ..., an, k1: v1, ..., km: vm)
in a scope that has access to the private members
of the class of o.
If the invocation returns a result r, this method returns
the result r.
If the invocation causes a compilation error
the effect is the same as if a non-reflective compilation error
had been encountered.
If the invocation throws an exception e (that it does not catch)
this method throws e.
Note that this method is not available in the corresponding dart:mirrors interface. It was added here because it enables many invocations of a reflectively chosen method on different receivers using just one reflective operation, whereas the dart:mirrors interface requires a reflective operation for each new receiver (which is in practice likely to mean a reflective operation for each invocation).
Required capabilities: invoker for an instance method requires a matching InstanceInvokeCapability or InstanceInvokeMetaCapability; invoker for a static method requires a matching StaticInvokeCapability or StaticInvokeMetaCapability; and invoker for a top-level function requires a matching TopLevelInvokeCapability or TopLevelInvokeMetaCapability.
// // TODO(eernst) doc: revise language on private members when semantics known. /// /// Required capabilities: [invoker] for an instance method requires a /// matching [InstanceInvokeCapability] or [InstanceInvokeMetaCapability]; /// [invoker] for a static method requires a matching /// [StaticInvokeCapability] or [StaticInvokeMetaCapability]; and [invoker] /// for a top-level function requires a matching [TopLevelInvokeCapability] /// or [TopLevelInvokeMetaCapability]. Function invoker(String memberName);