I'm using Eclipse JDT AST to parse a given java source code. While parsing the code, when it hits a method invocation, I want to find out whether that particular method returns or sets a value of an instance variable (basically to find out whether the callee method is a getter/setter of the same class of caller method).
E.g.:
public void test(){
//when parsing the following line I want to check whether "getName"
//returns a value of an instance variable.
String x = getName();
//when parsing the following line I want to check whether "setName"
//sets the value of an instance variable.
setName("some-name");
}
I've used the AST plugin also find out a possible path which would help me to refer it from the API, but couldn't.
Please let me know whether this is possible and if so, which approach that would help me to get the required information.
Don't think that there is an api which tells you whether a method is a getter or a setter.
You will have to write code to do this. For a getter, you can probably simply check if the last statement in the method is a return statement which returns an instance variable.
Related
I'm trying to implement specification in one of my use cases.
As u can see in the function dateValueBetween, I'm trying to get from the root the transient property valueDate. But when calling this service with real data it give the error downside.
My original problem was how to call the builder.between method but the value I have is a String value and need to be parsed.
but it seems that the first argument need to be a property of the table and not a function.
How can I achieve my goal?
After evolving my project code for months, I've finally hit a need to define a new class. Having to romp through my previous class definitions as a refresher of the conventions, I noticed that all constructors and property setters all have an output argument, even though nothing is assigned to it, e.g.:
function o = myConstructor( arg1, arg2, ... )
function o = set.SomeProperty( o, arg1 )
I've been looking through the documentation for upward of an hour without finding the explanation for this. It doesn't look like it depends on whether a function is defined in the class definition file or in its own separate m-file.
Can anyone please explain?
The best place to start is the documentation "Comparison of Handle and Value Classes". From the very top:
A value class constructor returns an object that is associated with the variable to which it is assigned. If you reassign this variable, MATLAB® creates an independent copy of the original object. If you pass this variable to a function to modify it, the function must return the modified object as an output argument.
A handle class constructor returns a handle object that is a reference to the object created. You can assign the handle object to multiple variables or pass it to functions without causing MATLAB to make a copy of the original object. A function that modifies a handle object passed as an input argument does not need to return the object.
In other words, value classes need to return a modified object (which is a new object distinct from the original), while handle classes don't. The constructor of either class will always have to return an object, since it is actually constructing it.
Some good additional reading is "Which Kind of Class to Use", which links to a couple helpful examples of each type of class object. Looking at the DocPolynom value class example, you can see that property set methods have to return the modified object, while the dlnode handle class example only requires an output for its constructor. Note that you could still return an object from a handle class method (if desired), but it's not required.
I wondering how to get object property value given name of property in string in Scala? I saw examples when you get all fields of object using Reflection and iterate over it. But is it possible to call it without iteration? Or may be there is a way to pass object.field to another function without evaluation and evaluate it there and return result?
Kolmar comment give me right direction to call by name function.
I just read that the init method can't be used as a value. Meaning:
var x = SomeClass.someClassFunction // ok
var y = SomeClass.init // error
Example found on Language reference
Why should it be like that? Is it a way to enforce language level that too dirty tricks come into place, because of some cohertion or maybe because it interferes with another feature?
Unlike Obj-C, where the init function can be called multiple times without problems, in Swift there actually is no method called init.
init is just a keyword meaning "the following is a constructor". The constructor is called always via MyClass() during the creation of a new instance. It's never called separately as a method myInstance.init(). You can't get a reference to the underlying function because it would be impossible to call it.
This is also connected with the fact that constructors cannot be inherited. Code
var y = SomeClass.init
would also break subtyping because the subtypes are not required to have the same initializers.
Why should it be like that?
init is a special member, not a regular method.
Beyond that, there's no reason that you'd ever need to store init in a variable. The only objects that could use that function in a valid way are instances of the class where that particular init is defined, and any such object will have already been initialized before you could possibly make the assignment.
Initializers don't have a return value. In order to assign it to something, it should be able to return something - and it doesn't.
In netbeans I use to call a method that returns a value, but I am directly calling it where I have to pass a parameter to the function i.e. Function(getValue()) where getValuue() returns String. So what I want to know is that what is more efficient way to call this method whether should I assign value to a string first and then pass that value to parameter, as netbeans suggests me and shows a warning there, or calling it directly is good? I know code runs fine but keeping in mind the efficiency or rules of coding should I consider this thing or not? Or how badly can it effect if I ignore it?
If you are only using that value once, then calling it directly where it is used as a parameter is fine.
In Java, this is fine:
MyClass myClass = new MyClass();
myFunction(myClass.getSomeValue());
Whereas in the following case:
MyClass myClass = new MyClass();
MyOtherClass myOtherClass = myClass.someLongComputation();
Int value = myFunction(myOtherClass);
anotherFunction(value, myOtherClass);
It may be better to have a local variable so that you avoid calling a long running calculation twice. However, for simple getValue()s, it really doesn't matter.