I'd like Scala compiler to show a deprecation warning whenever a particular function is found used. How can I achieve this?
I didn't notice the comment, kristian-domagala, so here is the example:
#deprecated("Reason this is old","01-08-2014")
def oldMethod = {
...
}
Annotate it as #deprecated.
Related
I would like to know if there is a way to do a cast from Single<Object> to Single<CustomClass>.
I have a class that implements a method that should return a Single<Customer>, I implemented the search like here
Single.create(single -> {
CustomerServiceDto customer = mapper.map(customerRepository.findById(id).get(), CustomerServiceDto.class);
single.onSuccess(customer);
});
There isn't any problem. It's what I need. This create returns me a Single<Customer> but when I implement another function to handling an exception
Single.create(single -> {
CustomerServiceDto customer = mapper.map(customerRepository.findById(id).get(), CustomerServiceDto.class);
single.onSuccess(customer);
}).onErrorReturn(error -> new CustomerServiceDto());
It returns me a Single<Object>. Can I do a casting here? To avoid change the method's signature. I tried with the classic (Single<Customer>) Single<Object> instance, but it isn't work. Thanks for your advice.
The answer was the #dano's comment. Thanks, #dano.
What is the most 'scala-ic' way to capture a value (possibly one that is not idempotent) for logging and returning the same value.
I can think of 'return' statement the only way to do it, but apparently using 'return' should be avoided in scala .
Use case:
def myfunc(argument) : ReturnType{
val response:ReturnType = dependency()
// dependency() is not idemptotent
// so calling more than once will have side-effects
logger.debug(response.member1 , response.member2)
return response
}
Is there a way to achieve this without using a 'return' keyword.
I am a newbie to scala so some (or most) of what I said could be wrong, and would be happy to be corrected.
Just reifying #Shadowlands answer.
def myfunc(argument: ArgType): ReturnType {
val response = dependency()
logger.debug(response.member1, response.member2)
response
}
I am trying to do something like this. However the WithMetadata method wont let me.
Is this a problem in Autofac and should TScanningActivatorData in the WithMetadata overloads be changed to TActivatorData, or am i approaching this the wrong way?
builder.RegisterType(myType).As<IMyType().AsSelf().WithMetadata("somekey", delegate(Type t)
{
//dosomething
return t;
});
This gives me the error on the WithMetadata method: The type 'Autofac.Builder.ConcreteReflectionActivatorData' cannot be used as type parameter 'TScanningActivatorData' in the generic type or method 'Autofac.RegistrationExtensions.WithMetadata<TLimit,TScanningActivatorData,TRegistrationStyle>(Autofac.Builder.IRegistrationBuilder<TLimit,TScanningActivatorData,TRegistrationStyle>, string, System.Func<System.Type,object>)'. There is no implicit reference conversion from 'Autofac.Builder.ConcreteReflectionActivatorData' to 'Autofac.Features.Scanning.ScanningActivatorData'.
There's a more suitable overload for what you're trying to achieve. The t parameter passed in to the delegate is the same as myType - so the equivalent code is:
var someValue = DoSomething(myType);
builder.RegisterType(myType)
.As<IMyType>()
.AsSelf()
.WithMetadata("somekey", someValue);
The overload you've been looking at is for use with scanning registrations, e.g. when using RegisterAssemblyTypes() rather than RegisterType().
Hope this helps.
Nick
I'm trying to write a class for a scala project and I get this error in multiple places with keywords such as class, def, while.
It happens in places like this:
var continue = true
while (continue) {
[..]
}
And I'm sure the error is not there since when I isolate that code in another class it doesn't give me any error.
Could you please give me a rule of thumb for such errors? Where should I find them? are there some common syntactic errors elsewhere when this happens?
It sounds like you're using reserved keywords as variable names. "Continue", for instance, is a Java keyword.
You probably don't have parentheses or braces matched somewhere, and the compiler can't tell until it hits a structure that looks like the one you showed.
The other possibility is that Scala sometimes has trouble distinguishing between the end of a statement with a new one on the next line, and a multi-line statement. In that case, just drop the ; at the end of the first line and see if the compiler's happy. (This doesn't seem like it fits your case, as Scala should be able to tell that nothing should come after true, and that you're done assigning a variable.)
Can you let us know what this code is inside? Scala expects "expressions" i.e. things that resolve to a particular value/type. In the case of "var continue = true", this does not evaluate to a value, so it cannot be at the end of an expression (i.e. inside an if-expression or match-expression or function block).
i.e.
def foo() = {
var continue = true
while (continue) {
[..]
}
}
This is a problem, as the function block is an expression and needs to have an (ignored?) return value, i.e.
def foo() = {
var continue = true
while (continue) {
[..]
}
()
}
() => a value representing the "Unit" type.
I get this error when I forget to put an = sign after a function definition:
def function(val: String):Boolean {
// Some stuff
}
Solved. IntelliJ didn't highlight the fact that my imports were incomplete.
Hi,
I have a simple Scala program that I'm trying to develop using jMock. Setting basic expectations works nicely but for some reason Scala does not understand my attempt to return a value from a mock object. My maven build spews out the following error
TestLocalCollector.scala:45: error: not found: value returnValue
one (nodeCtx).getParameter("FilenameRegex"); will( returnValue(regex))
^
And the respective code snippets are
#Before def setUp() : Unit = { nodeCtx = context.mock(classOf[NodeContext]) }
...
// the value to be returned
val regex = ".*\\.data"
...
// setting the expectations
one (nodeCtx).getParameter("FilenameRegex"); will( returnValue(regex))
To me it sounds that Scala is expecting that the static jMock method returnValue would be a val? What am I missing here?
Are you sure about the ';'?
one (nodeCtx).getParameter("FilenameRegex") will( returnValue(regex))
might work better.
In this example you see a line like:
expect {
one(blogger).todayPosts will returnValue(List(Post("...")))
}
with the following comment:
Specify what the return value should be in the same expression by defining "will" as Scala infix operator.
In the Java equivalent we would have to make a separate method call (which our favorite IDE may insist on putting on the next line!)
one(blogger).todayPosts; will(returnValue(List(Post("..."))))
^
|
-- semicolon only in the *Java* version
The OP explains it himself:
the returnValue static method was not visible, thus the errors.
And the will method just records an action on the latest mock operation, that's why it can be on the next line or after the semicolon :)
import org.jmock.Expectations
import org.jmock.Expectations._
...
context.checking(
new Expectations {
{ oneOf (nodeCtx).getParameter("FilenameRegex") will( returnValue(".*\\.data") ) }
}
)