Consider code
public List<Product> listProducts(){
HibernateCallback callBack=new HibernateCallback(){
public Object doInHibernate(Session session){
Query query=session.createQuery("from Product");
return query.list();
}
};
return (List<Product>)hibernateTemplate.execute(callBack);
}
Is there anything wrong with above code? In eclipse Helios it is showing following error:
The type new HibernateCallback(){} must implement the inherited abstract method HibernateCallback.doInHibernate(Session)
doInHibernate() is implemented then why it showing the above error?
Make sure that Session is org.hibernate.Session, not something else (e.g. org.hibernate.classic.Session).
The pair of org.hibernate.Session and org.hibernate.classic.Session is especially tricky - since the latter interface extends the former one, accidential mistake of this kind doesn't cause other problems and cannot be easily noticed.
Related
How a class can implement two interfaces with the same default method in Java 8.
I was not able to get the concept behind the same default method from different interfaces getting inherited in the sub class.Please explain the issue.
interface House {
default String getAddress() {
return "101 Main Str";
}
}
interface Bungalow extends House {
default String getAddress() {
return "101 Smart Str";
}
}
class MyHouse implements Bungalow, House {
}
public class TestClass {
public static void main(String[] args) {
House ci = new MyHouse(); //1
System.out.println(ci.getAddress()); //2
}
}
In the above code default method getAddress() in interface House is present.another method with the same name is declared as default in the extending interface Bungalow
How class MyHouse can implement both the interfaces without any compilation error(because it doesn't know which method has the preference in that case implementing should fail.)
If i call new MyHouse().getAddress(); gives compile error but it should give compilation error even without method calling from MyHouse class.
It seems that the answer is here, where there is a different example, but sort of makes sense and is really close to yours.
Ask me the exact same thing in 1/2 a year and I'll say it will fail at compile time and point me to this answer, so that I could read the JLS again. I guess this is how they decided to implement it. Without thinking too much, I, personally (may be wrong) think that this is at least counter intuitive...
i'm adding lots of bold because someone downgraded my question which is think is strange...
i went from this which worked which means things are configured correctly for #PreAuthorize...
#RestController
#RequestMapping('/people')
public PersonController extends BaseController {
#PreAuthorize("#pesonId != principal.id")
#RequestMapping(value="updatePerson", method={RequestMethod.POST}, produces = MediaType.APPLICATION_JSON_VALUE)
public #ResponseBody SimpleResponseStatus updatePerson(#RequestParam(personId) final Long personId, #RequestParam(value) final String value, final HttpServerRequest request, final HttpServletResponse response)
{
Person p = personRepo.findById(personId);
p.setValue(value);
personRepo.save(p);
}
}
and moved to this which doesn't work ... the #PreAuthorize in the Repository save()...
public interface PersonRepository extends JpaRepository<Person,Long> {
#SuppressWarnings("unchecked")
#Override
#PreAuthorize("#p.id != principal.id")
Person save(person p);
}
and now i get a "Failed to evaluate expression '#p.id != principal.id'
One difference between when it was working on the Controller was i did #personId and not #p.id so i don't know if the object vs primitive in the expression is the problem or if Controller vs Repository (where i do the evaluation) is the problem.
So i have a few questions...
Do i have to do anything special to get the PreAuthorize working in the Repository?
Nothing to do with Spring security but why was i forced to add the SuppressWarnings? i can see if i was returning List<Person> maybe but i thought that was strange.
There is another instance where i will want to do an a PreAuthorize expression like "#p.group.id != 3" ... is there a limit to the levels that can be in an evaluation? i.e. level = obj.obj.obj.obj.value
Another interesting thing is that when i had it working with the Controller i didn't need curly braces "#{userId != 3}" but it worked with "#userId != 3" and i got that syntax from here.
Bottom line, i had it working in a Controller but without an object parameter and now i need it to work in a Repository and with an object parameter. And i've tried #person.id != 3 as well as #{person.id != 3} and neither work.
i found the answer to my own question: here
which is basically for the Repository you have to add a parameter name via annotation since the debug isn't compiled into the interface.
it took me a long time to finally find the answer as it took trial and error of me trying different EL syntax and finally one syntax i chose gave me a different (and better) error message and from there i found the link above.
Anyway, whoever downgraded my question should have just posted the link i just did above instead of downgrading me. that is just mean, really.
public interface PersonRepository extends JpaRepository<Person,Long> {
#SuppressWarnings("unchecked")
#Override
#PreAuthorize("#p.id != principal.id")
Person save(#Param("p") person p); //the #Param annotation is needed!
}
also, it is interesting how some places i see {} are needed and other places not. i did not need braces for this to work.
you must first:
- enable global method security
in your spring security config just add
#EnableGlobalMethodSecurity(prePostEnabled=true)
the you can safely use #PreAuthorize and #PostAuthorize
correct SPEL syntax should be
#{pesonId != principal.id}
but...before this you should ensure both parameter are present in SPringEvaluationContext.
I suggest to use Spring approach, which doesn't fit you question but gives you a different point of view of the problem.
Usage of expression bases access control
https://docs.spring.io/spring-security/site/docs/3.0.x/reference/el-access.html
ex: #PreAuthorize("hasRole('ADMIN')")
Spring security accept any valid Spel inside annotation.
Take a look here:
http://www.baeldung.com/spring-security-expressions-basic
We have a lot of code in our code base that's similar to the following interface:
public interface SomethingService {
#Cacheable(value = "singleSomething")
Optional<Something> fetchSingle(int somethingId);
// more methods...
}
This works fine as long we're only using local caches. But as soon as we're using a distributed cache like Hazelcast, things start to break because java.util.Optional<T> is not serializable and thus cannot be cached.
With what I've come up so far to solve this problem:
Removing java.util.Optional<T> from the method definitions and instead checking for the trusty null.
Unwrapping java.util.Optional<T> before caching the actual value.
I want to avoid (1) because it would involve a lot of refactoring. And I have no idea how to accomplish (2) without implementing my own org.springframework.cache.Cache.
What other options do I have? I would prefer a generic (Spring) solution that would work with most distributed caches (Hazelcast, Infinispan, ...) but I would accept a Hazelcast-only option too.
A potential solution would be to register a serializer for the Optional type. Hazelcast has a flexibile serialization API and you can register a serializer for any type.
For more information see the following example:
https://github.com/hazelcast/hazelcast-code-samples/tree/master/serialization/stream-serializer
So something like this:
public class OptionalSerializer implements StreamSerializer<Optional> {
#Override
public void write(ObjectDataOutput out, Optional object) throws IOException {
if(object.isPresent()){
out.writeObject(object.get());
}else{
out.writeObject(null);
}
}
#Override
public Optional read(ObjectDataInput in) throws IOException {
Object result = in.readObject();
return result == null?Optional.empty():Optional.of(result);
}
#Override
public int getTypeId() {
return 0;//todo:
}
#Override
public void destroy() {
}
}
However the solution isn't perfect because this Optional thing will be part of the actual storage. So internally the Optional wrapper is also stored and this can lead to problems with e.g. queries.
I have a code that looks like this
public class EmployeeController : Controller
{
public ContextWrapper contextWrapper;
public EmployeeController (IContextWrapper wrapper)
{
contextWrapper = wrapper;
}
In my dependency resolver I have the binding for IContextWrapper
kernel.Bind<IContextWrapper>().To<ContextWrapper>();
The implementation of ContextWrapper has an object which is of type Linq DataContext.
public class ContextWrapper : IContextWrapper
{
public MyDataContext dataContext;
public ContextWrapper(MyDataContext context)
{
this.dataContext = context;
}
Now my action method in this controller looks like this
var empRepository = new EmployeeRepository(contextWrapper);
//do some tests with this repository.
some values = contextWrapper.datacontext.get some values from the database table
//do some tests with these values.
To be able to test this method
I should be able to provide some sort of mock database(not literally) or
make the contextWrapper.datacontext return mocked values or
I even thought of creating another implementation of the IContextWrapper that doesn't use a Linq DataContext object. And creating another constructor for this controller and pass that fake implementation. Also in my dependency resolver I would bind the fake object to the IContextWrapper. Although I do not know how to make Ninject
As a last resort test my method against a test database since it all boils down to this Linq DataContext object and it seems I cannot get rid of it past a certain level.
Problem is the more I read about it, more I get confused. I have tried to give as much detail as possible to explain my problem. If any one has a clear cut idea about how to get this, please suggest.
I'm new to RhinoMocks, and trying to get a grasp on the syntax in addition to what is happening under the hood.
I have a user object, we'll call it User, which has a property called IsAdministrator. The value for IsAdministrator is evaluated via another class that checks the User's security permissions, and returns either true or false based on those permissions. I'm trying to mock this User class, and fake the return value for IsAdministrator in order to isolate some Unit Tests.
This is what I'm doing so far:
public void CreateSomethingIfUserHasAdminPermissions()
{
User user = _mocks.StrictMock<User>();
SetupResult.For(user.IsAdministrator).Return(true);
// do something with my User object
}
Now, I'm expecting that Rhino is going to 'fake' the call to the property getter, and just return true to me. Is this incorrect? Currently I'm getting an exception because of dependencies in the IsAdministrator property.
Can someone explain how I can achieve my goal here?
One quick note before I jump into this. Typically you want to avoid the use of a "Strict" mock because it makes for a brittle test. A strict mock will throw an exception if anything occurs that you do not explicitly tell Rhino will happen. Also I think you may be misunderstanding exactly what Rhino is doing when you make a call to create a mock. Think of it as a custom Object that has either been derived from, or implements the System.Type you defined. If you did it yourself it would look like this:
public class FakeUserType: User
{
//overriding code here
}
Since IsAdministrator is probably just a public property on the User type you can't override it in the inheriting type.
As far as your question is concerned there are multiple ways you could handle this. You could implement IsAdministrator as a virtual property on your user class as aaronjensen mentioned as follows:
public class User
{
public virtual Boolean IsAdministrator { get; set; }
}
This is an ok approach, but only if you plan on inheriting from your User class. Also if you wan't to fake other members on this class they would also have to be virtual, which is probably not the desired behavior.
Another way to accomplish this is through the use of interfaces. If it is truly the User class you are wanting to Mock then I would extract an interface from it. Your above example would look something like this:
public interface IUser
{
Boolean IsAdministrator { get; }
}
public class User : IUser
{
private UserSecurity _userSecurity = new UserSecurity();
public Boolean IsAdministrator
{
get { return _userSecurity.HasAccess("AdminPermissions"); }
}
}
public void CreateSomethingIfUserHasAdminPermissions()
{
IUser user = _mocks.StrictMock<IUser>();
SetupResult.For(user.IsAdministrator).Return(true);
// do something with my User object
}
You can get fancier if you want by using dependency injection and IOC but the basic principle is the same across the board. Typically you want your classes to depend on interfaces rather than concrete implementations anyway.
I hope this helps. I have been using RhinoMocks for a long time on a major project now so don't hesitate to ask me questions about TDD and mocking.
Make sure IsAdministrator is virtual.
Also, be sure you call _mocks.ReplayAll()
_mocks.ReplayAll() will do nothing. It is just because you use SetupResult.For() that does not count. Use Expect.Call() to be sure that your code do everything correct.