Using reflection to get method body

Hi,
I'm just getting into this side of program and while I understand the use of reflection in oredr to obtain the constructor and method, parameters, fields etc I was wondering if its possible to grab the method body and copy it into a string.
So for example in the following class...
class MyClass
private String str;
MyClass(){}
public String MyMethod(String s)
str=s;
str=str+" was the String";
System.out.println(str);
return str;
...I need to capture just this code..
str=s;
str=str+" was the String";
System.out.println(str);
return str;
...as a string
The reason i need to do this is that I'm programming a mechanism for storing objects and their methods using JDBC.. I could use object serialisation and store as a blob, but I'm wanting to store the attributes of a class as seperate parts so I can retrieve bits of code from the database at some later time.
Thanks for any help you might give me
peace
neil

You say that you are trying to store the method body
into a database. This is to allow you to store an
object and its methods into a database. Are you trying
store the method text or its implementation (i.e class
or java). If it is the implementation then just
serialize the found method object using reflection.
WHY are you doing this ?? what about private methods,
class variables, class methods ???Hi, yes it is confusing to explain, but I'm experimenting with a new programming paradigm called AspectJ and I've only just got into Reflection. I'm creating a repository of Aspects (same as classes but with added functionality and some limitations) with JDBC and don't want to just serialise the object as a blob and so have created data tables to hold different parts of the anatomy of an Aspect and this was the only thing I was getting stuck on.
The idea is that the user is able to recall these whole aspects (or a part of them such as a method) on the fly and use them in a program. I realise that ther will be problems because these methods may have other dependencies such as the ones you explain above but its just experimental at the moment and those are the kinds of things I'm wanting to find out more.
I've seen examples of reflection for Objects but never for methods. So it is possible to capture just a method by serialisation using reflection? Any examples would be much appreciated.
Peace
Neil

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Gary

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I use accessor methods when writing persistent
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The
main benefit being that should you need to refactor
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Must I Use Reflection?

Hi, i posted here this question, �cause it�s about DB and JDBC.
I`m coding a simple visual program, to connect with JDBC.
i have a field, who capture the path of the DB, and i need to get form there, the string:
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must i use reflection to get it?
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Your question makes no sense.
The value you posted represents the name of a particular JDBC driver.
The string itself is a string. Nothing more. Nothing less. You can get it anywhere you can get a string from. Like a text file, a properties file, a command line option, hard coded etc. Just like you can do the same with other string values.
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No perhaps you mean the driver itself and not the string?
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Calling a pkg from managed code and then using reflection to call a method from a script task

Hi we run 2012 std. I have some pretty good evidence that when I call my pkg from a .net service, a script component in that pkg fails when trying 2 use reflection to load and invoke our .net message history method. The exception is either on
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we have 2 theories after showing the exception trace to folks who r more adept at managed code.
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This link came up as well and has something to do with ILMerge and workarounds to ILMerge.
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Finally, this link came up and seems to have something to do with embedding your dlls in one assembly without them losing their identity.
http://blogs.msdn.com/b/microsoft_press/archive/2010/02/03/jeffrey-richter-excerpt-2-from-clr-via-c-third-edition.aspx
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How to access private method of an inner class using reflection.

Can somebody tell me that how can i access private method of an inner class using reflection.
There is a scenario like
class A
class B
private fun() {
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Can i use reflection in someway to access this private method fun() in class c.

I suppose for unit tests, there could be cases when you need to access private methods that you don't want your real code to access.
Reflection with inner classes can be tricky. I tried getting the constructor, but it kept failing until I saw that even though the default constructor is a no-arg, for inner classes that aren't static, apparently the constructor for the inner class itself takes an instance of the outer class as a param.
So here's what it looks like:
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//this is what I mention above.
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meth.setAccessible(true);
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meth.invoke(inner);
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Good luck, and if you find yourself relying on this too much, it might mean a code redesign.

Getting Method objects without reflection

This is a shameless plug to try to get votes for a recent bug I've filed:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6356762
For a long time, it's bothered me that there is no way other than reflection to obtain Method and Field objects to identify components of classes. It should be possible to write something like MyClass.class.nameOfMyField to obtain the FIeld object directly. With the current reflection-only method, one has to obtain these by looking up their String names. So:
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-it's inelegant to use Strings to perform at runtime what the compiler should be able to do at compile time
One of the most immediate uses for this could be with classes conforming to the Beans pattern. Instead of specifying String names directly when firing property change events (whilch always risks a typo cauing a hard to trace error), you could obtain the coresponding Field object and call getName() on it.
If something like this could be provided in Mustang, I would be in seventh heaven. Please vote for the bug, or let me know what you think about this.

I would definately have usage of that. I've always loved function pointers in C, and jump tables in assembler.
Kaj

Reflection cant get parameterized method signature?

my sample:
interface Root<T>{
public void prt(T t );
interface A extends Root<String>{
public class Reflecttest {
public static void main(String[] args){
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That information doesn't exist at runtime. It is all
erased to Object by the compiler. That's what
Generics does - safe type erasurefurther, you don't need to know, since by using reflection you're basically bypassing compile-time type safety altogether. reflection and generics have totally different intents, and don't mix well together

Reflection: result of getting Methods

Hi
I'm using reflection to see what methods a class has. When I do reflection on java.awt.Button I get the same method occuring more than once. (At the moment my code is a little rough around the edges so it might just be my code.) My Question: Do all overriden (potentially abstract) methods get listed by getMethods(). If this is the case which one of the two (or more) methods do I call invoke on?

Methods in Java can be overridden and overloaded. Overloaded methods are distinguished by their signature, that is basically the list of parameters that a method is passed including the null or empty list.
Overridden methods are methods which override a method from an inherited class.
To query a class for locally declared methods you need to call getDeclaredMethods. The returns an array of Method objects for all methods declared specifically by the queried class.
To query a class about ALL publicly declared methods then you call getMethods, this method returns an array of Method instances that are exposed by the class in question and ALL inherited classes.
API information about querying a class for its properties can be found in the JavaDocs for java.lang.Class.
The Method class has methods which are useful in determining things like access modifiers, thrown exceptions, parameter list etc.
API information about Reflection and things like the Method class can be in the JavaDocs for java.lang.reflect package.
It is also worth looking at the java.beans package(s) in detail as well, there are things in there that can of great use to you when dealing with Reflection and Introspection.

Using reflection to get method body

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