Package jakarta.enterprise.invoke
Interface InvokerBuilder<T>
- Type Parameters:
T
- type of outcome of this builder; always represents anInvoker
, but does not necessarily have to be anInvoker
instance directly
public interface InvokerBuilder<T>
Builder of
Invoker
s. Allows configuring additional behaviors on top of a plain
method invocation.
Lookups
For the target bean instance (withInstanceLookup()
) and for each target method
parameter (withArgumentLookup(int)
), it is possible to specify that the corresponding
value passed to Invoker.invoke()
shall be ignored and a value shall be looked up
from the CDI container instead.
For example, assume the following managed bean exists:
@Dependent public class MyService { public String hello(String name) { return "Hello " + name + "!"; } }A CDI-based framework may want to build an invoker for the
hello()
method that
automatically looks up MyService
from the CDI container, instead of having to
obtain a contextual reference manually.
Assuming that builder
is an InvokerBuilder
for MyService.hello()
,
such invoker can be built:
builder.withInstanceLookup().build();Later, to invoke the
hello()
method, a framework could pass null
as the instance:
invoker.invoke(null, new Object[] { "world" })The invoker would look up the instance of the target bean automatically, so the method would be invoked correctly and the return value would be
"Hello world!"
.- Since:
- 4.1
-
Method Summary
Modifier and TypeMethodDescriptionbuild()
Returns the builtInvoker
or some representation of it.withArgumentLookup
(int position) Enables lookup of the argument on givenposition
.Enables lookup of the target bean instance.
-
Method Details
-
withInstanceLookup
InvokerBuilder<T> withInstanceLookup()Enables lookup of the target bean instance.- Returns:
- this builder
-
withArgumentLookup
Enables lookup of the argument on givenposition
.- Parameters:
position
- zero-based position of the target method parameter for which lookup should be enabled- Returns:
- this builder
- Throws:
IllegalArgumentException
- ifposition
is less than 0 or greater than or equal to the number of parameters declared by the target method
-
build
T build()Returns the builtInvoker
or some representation of it. Implementations are allowed but not required to reuse already built invokers when possible.- Returns:
- the built invoker
-