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JAVA REFLECTION GET RETURN FROM METHOD WITH ARGUMENT CODE

It could be used to get some required data from the original class if needed. In the new class, create a private field for storing a reference to an instance of the class in which the method was previously located. Lets look at this example to list of methods and return types of java.lang. Java reflection is one of the powerful features of java. Name it based on the purpose of the method that you’re refactoring.

Then call the getReturnType() on Method object to get the return type.

Call getDeclaredMethods() method from the Class instance which returns the Method array which contains all the methods whether it is private, public or default.

Call getMethods() method from the Class instance which returns the Method array which contains the public methods.

In this example get the Class instance of Math class.

Get the Class instance of the class which you want to list the methods.

You can list the public and private methods of an object using the following steps: Is it possible that this is the issue? And if yes, is there a workaround?ĮDIT 2: As requested, here is the Stack Trace for the exception I am getting: Īt 0(Native Method)Īt (Unknown Source)Īt (Unknown Source)Īt .invoke(Unknown Source)Īt (Reflector.java:275)Īt (Reflector.java:134)Īt (Reflector.java:69)Ĭaused by: Īt .GetPropDirect(IDDocument.java:739)Īt it.(Contribuente.In this example we shall explain with a simple example to get the methods of a class using the reflection and get the return type. So, perhaps it's internally trying to invoke another method which belongs to a superclass, and I do not instantiate the superclass. In the source of the class where the method is declared, here is the declaration of the method: public IDVariant getSomeValue() Obtaining Method Objects The Method class is obtained from the Class object. We use two methods for this purpose as described below before moving ahead as follows: Method 1: getDeclaredMethod (): It creates an object of the method to be. We can invoke a method through reflection if we know its name and parameter types. This text will get into more detail about the Java Method object. The getMethods () method is used to get the public methods of the class to which an object belongs. I am invoking a sample method, say getSomeValue. Using Java Reflection you can inspect the methods of classes and invoke them at runtime. I cannot change that code, however, as it is coming from an external tool which generates it automatically.ĮDIT: Okay, so I've had a better look at the source produced by the external tool, and this is what I gather:

JAVA REFLECTION GET RETURN FROM METHOD WITH ARGUMENT CODE

NOTE: The function returns indeed a variable of type IDVariant, I have checked the source code out. String type = decodeType((IDVariant)idv) // function which maps internal codes of IDVariant default type to primitive and internal types Object idv = method.invoke(o, noparams) // exception occurs at this point

Object o = toParse.newInstance() // There is a default constructor with no values, the object is not null Tha variable className is given.Ĭlass toParse = Class.forName(className) If anyone has any idea, I would be most appreciative! :)įollowing is a sample code fragment: // Edit of the code, as correctly indicated by cyon. It's the only logical explanation I have been able to give. It seemed like a good idea, but it's not working: I am getting an InvocationTargetException which, I presume, is due to the fact that the instance of the class I create in order to call the method, is in fact not populated with data. What I have tried doing is retrieving the get method for each property of each class, then invoking it and checking the default type of each IDVariant. The only problem is, I have not come up with a way to find out the default type of the IDVariant, and thus having the correct type for each variable of the XML tree. Obviously, the way to go is Reflection, and I have been successful so far in recreating the structure of the whole thing. I need to create a tool which parses a super-structure of classes recursively and recreate this structure in XML. Now, this class, as mentioned, is used as a general placeholder in much bigger and more complex classes. Since there are mainly two types of class in java, i.e. Hence, I can have: IDVariant v = new IDVariant(1) Īnd so on, but the default type would be int, as per the type of the parameter used to create the instance. Returns the number of formal parameters (whether explicitly declared or implicitly declared or neither) for the executable represented by this object. Convert Object to String in java using toString method of Object class or String.valueOf (object) method. This wrapper class (called IDVariant) has a default type which indicates the principal type of variable stored. I've got a wrapper class which is used for generically passing arguments to methods and subsequently retrieving values. Yes, I know there are plenty of articles on the topic, but it's not that simple.