Deadbolt 2.5.0, unable to instantiate custom SubjectPresentHandler extending AbstractDeadboltHandler - deadbolt

Question

I am using deadbolt 2.5.0 and I have created custom SubjectPresentHandler as below:
public class SubjectPresentHandler extends AbstractDeadboltHandler
{
public SubjectPresentHandler(ExecutionContextProvider ecProvider) {
super(ecProvider);
}
// other required methods
}
And, I also have :
#Singleton
public class CustomDeadboltHandlerCache implements HandlerCache
{
private final DeadboltHandler defaultHandler = new SubjectPresentHandler();
// other required code
}
Now the problem that I am facing here is I cannot instantiate SubjectPresentHandler using its default contructor. I get an error as: "The constructor SubjectPresentHandler is undefined". Now when I add default constructor in SubjectPresentHandler as below:
public SubjectPresentHandler() {
super();
}
I get an error as:
The constructor AbstractDeadboltHandler is undefined. If I try removing the paramaterized constructor in SubjectPresentHandler then I get error message as
"Implicit super constructor AbstractDeadboltHandler() is undefined for default constructor. Must define an explicit constructor".
I am not sure how can I resolve this, thus seeking solution regarding this issue.

Answer 1

The constructor of SubjectPresentHandler takes an ExecutionContextProvider as a parameter. The easiest way to do this is to inject one and have the creation of the handler done via Guice.
The ExecutionContextProvider is provided by DeadboltModule - you can see this here.
#Singleton
public class SubjectPresentHandler extends AbstractDeadboltHandler
{
#Inject
public SubjectPresentHandler(ExecutionContextProvider ecProvider) {
super(ecProvider);
}
// other required methods
}
You can also inject the handler into the handler cache:
#Singleton
public class CustomDeadboltHandlerCache implements HandlerCache
{
private final DeadboltHandler defaultHandler;
#Inject
public CustomDeadboltHandlerCache(final DeadboltHandler defaultHandler) {
this.defaultHandler = defaultHandler;
}
// other required code
}
If you have multiple handlers, take a look at the documentation for how to handle this.