src/main/java/com/github/oxo42/stateless4j/StateConfiguration.java
public StateConfiguration<S, T> onEntry(final Action1<Transition<S, T>> entryAction) {
        assert entryAction != null : ENTRY_ACTION_IS_NULL;
        representation.addEntryAction(new Action2<Transition<S, T>, Object[]>() {
            @Override
            public void doIt(Transition<S, T> arg1, Object[] arg2) {
                entryAction.doIt(arg1);
            }
        });
        return this;
    }
public StateConfiguration<S, T> onEntry(final Action1<Transition<S, T>> entryAction) {
        assert entryAction != null : ENTRY_ACTION_IS_NULL;
        representation.addEntryAction(new Action2<Transition<S, T>, Object[]>() {
            @Override
            public void doIt(Transition<S, T> arg1, Object[] arg2) {
                entryAction.doIt(arg1);
            }
        });
        return this;
    }
Specify an action that will execute when transitioning into the configured state

@param entryAction Action to execute, providing details of the transition
@return The receiver