Package jakarta.enterprise.invoke

Interface Invoker<T,R>

Type Parameters:

T - type of the target bean

R - return type of the target method

public interface Invoker<T,R>

An invoker allows indirect invocation of its target method on an instance of its target bean.

CDI-based frameworks are expected to use invokers when they need to invoke application methods. Applications are not supposed to use invokers, as they can invoke their own methods directly.

For example, assume the following managed bean exists:

 @Dependent
 public class MyService {
     public String hello(String name) {
         return "Hello " + name + "!";
     }
 }
 

Further, assume that invoker is an invoker for the hello() method of the MyService bean and myService is a contextual reference for the bean. Then, to invoke the hello() method indirectly, a framework would call

 invoker.invoke(myService, new Object[] { "world" })
 

The return value would be "Hello world!".

Since:

4.1

See Also:

invoke(Object, Object[])

Method Summary

Modifier and Type	Method	Description
R	invoke(T instance, java.lang.Object[] arguments)	Invokes the target method on the given instance of the target bean, passing given arguments.

Method Detail

invoke

R invoke(T instance,
         java.lang.Object[] arguments)
  throws java.lang.Exception

Invokes the target method on the given instance of the target bean, passing given arguments. If the target method returns normally, this method returns its return value, unless the target method is declared void, in which case this method returns null. If the target method throws an exception, it is rethrown directly.

Parameters:

instance - the instance of the target bean on which the target method is to be invoked; may only be null if the target method is static

arguments - arguments to be passed to the target method; may only be null if the target method declares no parameter

Returns:

return value of the target method, or null if the target method is declared void

Throws:

java.lang.RuntimeException - when instance or arguments are incorrect

java.lang.Exception - when the target method throws an exception