Given a relatively simple class
class TestNull {
static void main(String [] a) {
Long whatever = 1
// this works
new Runnable() {
void run() { println(whatever) }
}.run()
// this doesn't
new Weird() {
#Override
void x() { println(whatever) } // NPE
}
}
static abstract class Weird {
Weird() { x() }
abstract void x();
}
}
executing main() throws an NPE trying to access whatever during the construction of anonymous class extending Weird. The same code works fine in Java, and it also works fine as long as the variable is accessed after the class is constructed (hence the example with anonymous Runnable).
I wonder what's going on here, whether this is a Groovy bug (I'm testing with 3.0.5), or it's supposed to be like that. But then I'm not sure what exactly is null in this case, and how do you even logically explain what the rule is for accessing external scope variables from anonymous classes...
NPE:
Exception in thread "main" java.lang.NullPointerException
at org.example.TestNull$2.x(TestNull.groovy:15)
at org.example.TestNull$Weird.<init>(TestNull.groovy:20)
at org.example.TestNull$2.<init>(TestNull.groovy)
at org.example.TestNull.main(TestNull.groovy:13)
Related
I've been trying to setup some unit tests to verify the logic in a ForeachWriter custom implementation but am running into a bit of mocking / duplication trouble.
I'd like to Mock an injected dependency in the ForeachWriter, but my mocks seem to be duplicated during execution. Originally I thought the mocked dependencies weren't getting called, but during debug inspection I've found that multiple versions of them seem to exist (based on hashCode).
Here's some quick sample code of what I've been trying to do:
//Class I'd like to test
public class TestForeachSink extends ForeachWriter<String> {
#Inject
SomeDependency dep;
public TestForeachSink(SomeDependency dep) {
this.dep = dep;
}
#Override
public boolean open(long partitionId, long version) {
dep.doSomethingStartupRelatedOrThrow();
return true;
}
#Override
public void process(String value) {
dep.processSomething(value);
}
#Override
public void close(Throwable errorOrNull) {
dep.closeConnections();
}
}
//Testing Class
public class TestForeachSinkTests {
#Mock SomeDependency _dep;
TestForeachSink target;
#BeforeEach
public void init() {
_dep = mock(SomeDependency.class, withSettings().serializable());
target = new TestForeachSink(_dep);
}
#Test
pubic void shouldVerifyDependencyInteractions() {
//setup stream, add data to it
stream.toDS().writeStream().foreach(target).start().processAllAvailable();
//VERIFY INTERACTIONS WITH MOCK HERE
}
}
The added data runs through the stream as expected but it seems like the mock I've passed in of SomeDependency is replaced during execution with a copy. I think that makes sense if the execution is running as though it were performing on a separate worker, but I'd still like to be able to test the ForeachWriter.
Is anyone else testing this part of the code? I haven't come across any other tests for ForeachSink custom implementations but direction on moving forward would be very appreciated!
I'm coding in Groovy and am having trouble with the Java 8 #Repeatable meta-annotation. I think I'm doing everything right, but it appears that Groovy is not recognizing #Repeatable. Here's my sample code; I'm expecting the information from both annotations to get stored in MyAnnotationArray:
import java.lang.annotation.*
class MyClass
{
#MyAnnotation(value = "val1")
#MyAnnotation(value = "val2")
void annotatedMethod()
{
println("annotated method called")
}
public static void main(String... args)
{
MyClass ob = new MyClass()
ob.annotatedMethod()
java.lang.reflect.Method m = ob.getClass().getMethod("annotatedMethod")
List annos = m.getAnnotations()
println("annos = $annos")
}
}
#Target(ElementType.METHOD)
#Retention(RetentionPolicy.RUNTIME)
#Repeatable(MyAnnotationArray)
public #interface MyAnnotation
{
String value() default "val0";
}
public #interface MyAnnotationArray
{
MyAnnotation[] MyAnnotationArray()
}
What happens is that I get this error:
Caught: java.lang.annotation.AnnotationFormatError: Duplicate annotation for class: interface MyAnnotation: #MyAnnotation(value=val2)
java.lang.annotation.AnnotationFormatError: Duplicate annotation for class: interface MyAnnotation: #MyAnnotation(value=val2)
Which is exactly what I get if I leave out the #Repeatable meta-annotation.
The code works fine if I leave out one of the duplicate MyAnnotations; then there is no error, and I then can read the annotation value as expected.
Is it possible that Groovy doesn't support the #Repeatable meta-annotation? I couldn't find any documentation that states this outright, though this page hints that maybe this is the case (scroll down to item 88).
seems to be not supported
i used java 1.8 and groovy 2.4.11
after compiling and de-compilig the same code i got this:
java:
#MyAnnotationArray({#MyAnnotation("val1"), #MyAnnotation("val2")})
public void annotatedMethod()
{
System.out.println("annotated method called");
}
groovy:
#MyAnnotation("val1")
#MyAnnotation("val2")
public void annotatedMethod()
{
System.out.println("annotated method called");null;
}
so, as workaround in groovy use
//note the square brackets
#MyAnnotationArray( [#MyAnnotation("val1"), #MyAnnotation("val2")] )
public void annotatedMethod()
{
System.out.println("annotated method called");
}
full script (because there were some errors in annotation declaration)
import java.lang.annotation.*
class MyClass
{
//#MyAnnotation(value = "val1")
//#MyAnnotation(value = "val2")
#MyAnnotationArray( [#MyAnnotation("val1"), #MyAnnotation("val2")] )
public void annotatedMethod()
{
System.out.println("annotated method called");
}
public static void main(String... args)
{
MyClass ob = new MyClass()
ob.annotatedMethod()
java.lang.reflect.Method m = ob.getClass().getMethod("annotatedMethod")
List annos = m.getAnnotations()
println("annos = $annos")
}
}
#Target(ElementType.METHOD)
#Retention(RetentionPolicy.RUNTIME)
#Repeatable(MyAnnotationArray)
public #interface MyAnnotation
{
String value() default "val0";
}
#Retention(RetentionPolicy.RUNTIME)
public #interface MyAnnotationArray
{
MyAnnotation[] value()
}
also tried against groovy 3.0.0-SNAPSHOT - the result is the same as for 2.4.11
Yes, Groovy has supported "repeatable" annotations for a long time even in Java 5 so long as retention policy was only SOURCE. This is what allows multiple #Grab statements for instance without the outer #Grapes container annotation. Being only retained in SOURCE makes them useful for AST transformations and within the Groovy compiler itself (and other source processors) but not really useful anywhere else. We don't currently support #Repeatable at all but plan to in a future version.
I'm calling a Java method from Groovy which expects an instance of a SAM interface as a parameter.
Normally Groovy is happy with passing in a closure in these cases, and will coerce it accordingly HOWEVER in this case, the interface extends another one and overrides the single method.
Note - It still only has one method, but it's been overriden.
In this instance Groovy doesn't automatically coerce the closure and the only way I seem to be able to call it is by using "AS".
I'm publishing an API to help kids to learn code and really don't want them to have to use "AS" because it would complicate things.
Here's some code that shows the issue...
Java
public interface BaseHandler<T> {
public void handle(T test);
}
public interface Handler extends BaseHandler<String> {
public void handle(String test);
}
public class LibraryClass {
public void method(Handler handler) {
handler.handle("WORLD!");
}
}
Groovy
LibraryClass bar = new LibraryClass();
bar.method({ name -> println "HELLO " + name})
Error
Caught: groovy.lang.MissingMethodException: No signature of method: Bar.doIt() is applicable for argument types: (testClosures$_run_closure1) values: [testClosures$_run_closure1#fe63b60]
Any help on how to get around this without using "AS" would be hugely appreciated
Groovy wants to implement the interface by coercion, but doesn't know which interface method it should implement. As there are 2:
the handle(String test) and a second one: handle(String test) (of the baseHandler)
The solution is to remove the handle(String test) from the handler (it adds nothing as the BaseHandler posesses this method already thanks to the generics).
Like this it works correctly:
public interface BaseHandler<T> {
public void handle(T test);
}
public interface Handler extends BaseHandler<String> {
}
public class LibraryClass {
public void method(Handler handler) {
handler.handle("WORLD!");
}
}
I am testing a legacy code that use inheritance method. I am trying to mock super-method
to verity if the super-method is being call or not.
#RunWith(PowerMockRunner.class)
public class HumanTest {
#Test
public void test() throws NoSuchMethodException, SecurityException {
// 1. arrange
Human sut = PowerMockito.spy(new Human());
PowerMockito.doNothing().when((SuperHuman) sut).run(); // SuperHuman is the parent class
// 2. action
sut.run();
// 3. assert / verify
}
}
public class Human extends SuperHuman {
#Override
public void run() {
System.out.println("human run");
super.run();
}
}
public class SuperHuman {
public void run() {
System.out.println("superhuman run");
}
}
I was expecting that "human run" will be printed. But the actual result was none printed.
PowerMockito.doNothing().when((SuperHuman) sut).run(); // SuperHuman is the parent class
This won't work in your case since PowerMockito will mock method of Human even if you made cast.
I checked your code example and could say that it is possible to suppress invocation of super class method with:
Method toReplace = PowerMockito.method(SuperHuman.class, "run");
PowerMockito.suppress(toReplace);
But it seems that method replacment feature does not work for methods of super class:
createPartialMock should support mocking overridden methods in super classes.
So this does not work:
PowerMockito.replace(toReplace).with(new InvocationHandler() {
#Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
System.out.println("Method of superclass has been invoked !");
return null;
}
});
But still you should be able to verify invocation of super method let's say indirectly, by mocking other classes which are invoked in super method only.
For instance check that System.out.println was invoked with "superhuman run" or something like this.
I've been stuck on this all morning, even though it seems like it should be very easy (wondering if I'm missing something fundamental). I have the following code in a class-
public class myClass
{
private Dispatcher m_Dispatcher;
private void myMethod() { ... }
private void invokeTheMethod(object sender, PropertyChangedEventArgs e)
{
m_Dispatcher.Invoke(myMethod); //XYZ
}
}
The dispatcher is attached to the thread that instance of myClass is running on. The invokeTheMethod method is called from another thread, and I'd like to run myMethod on the thread of m_Dispatcher. However, if I try to run this code, I get an exception at XYZ saying "Object reference not an instance of an object". Is this because I haven't declared myMethod in the form of a delegate? - I have tried different ways to declare myMethod as a delegate, but I can't get any of them to compile. Any suggestions are very much appreciated.
Thanks,
Chris
The error you get
Object reference not an instance of an object (NullReferenceException)
refers to the field m_Dispatcher. It is null. That is why you cannot call the Invoke method on it.
Even if there is an instance of Dispatcher "attached to the thread", there is no way for myClass to get hold of that instance.
What you could do is to supply the instance of Dispatcher to myClass when you create an instance of myClass. Something like this:
public class myClass
{
// Here is the 'injection' of the instance in the constructor of this class
public myClass(Dispatcher dispatcher) {
m_Dispatcher = dispatcher;
}
private Dispatcher m_Dispatcher;
private void myMethod() { ... }
private void invokeTheMethod(object sender, PropertyChangedEventArgs e)
{
m_Dispatcher.Invoke(myMethod); //XYZ
}
}
As a side note, you should read up some on coding conventions as your casing is considered wrong by the majority of the C# development community. Here is a good start: http://msdn.microsoft.com/en-us/library/vstudio/w2a9a9s3.aspx