Reflection class

I have a problem. We can use reflector class to get the class name, method names and class variables. But is it possible to get method variables using the same logic?
Please help. Thanks in advance.

Ack! I didn't read the OP carefully - kajbj is actually correct: there is no way to get method variables (those private to a method) through reflection. They are not part of the class/method "signature," which is all that reflection is built to use.
Besides, accessing method variables won't accomplish anything - they have no meaning or context outside of the logic (method) they're being executed in.

Similar Messages

Reflection class isn't reflecting

i've added this reflection class
http://www.adobe.com/devnet/flash/articles/reflect_class_as3.html
to this simple .fla file, but i can't see any reflection
http://www.5y1.com/px02.zip
thank You for your help

quote:
Originally posted by:
NedWebs
You're not likely to get people to research your links and
files for you. If you can describe what steps/code you implemented
you'll stand a better chance of getting some help.
The file i've created is so simple that reading how i've
added the reflect class is just a waste of time

Reflection Classes with the same name

Hi!
I have a big problem with reflection. I want to reflect lots of stuff (methods, variables...) in a lot of classes with the same name immediately one after the other. It's like
copy the file for the analysis to the right place
do reflection and get results
copy next file for analysis
Important to note is, that all of the files that should be reflected have the same name.
When I run the programm, he always only reflects the first file I gave for analysis, although I know the copying-stuff works and the new file would be there for analysis (but he does not seem to load/use it).
Any ideas what i could do?
Thanks!
ET

I'm not sure if i'm authorised to tell too much
details, but i have to do some automated software
analysis and therefore I need to know whats inside of
a class and string search would not be appropriate.Why not ? What aspects of the class are you trying to examine ?
They have the same name, because they are delivered in
that form from a third party and it would be too much
effort (and to much risk of errors) to rename them.Sure, if they're delivered as class files, you're unable to rename them. Without knowing more I can't advise you further.
Why are you interested that much in that topic? Do you
have to perform a similar task?No, I'm trying to determine if reflection is the right tool for the job. Frankly it doesn't sound like it is. But since you're not authorised to tell me more, I can't help you more.
Dave.

Reflection - class.getConstructor question

package my.util;
class Test {
String s;
int i;
public Test(String s, int i){}
I want to do the following
Class c = Class.forName("my.util.Test");
Constructor con = c.getConstructor(new Class[] { String.class, int.class});
Test t = con.newInstance(new Object[] {"al",5});
The above obviously won;t compile because I can;t pass primitives to the object array at the time of creating the instance and I cannot do int.class when getting the
constructor. How do I then use reflection to achieve the
above..?

The above obviously won;t compile because I can;t
pass primitives to the object array at the time of
creating the instance and I cannot do int.class when
getting the constructor.you can use int.class. this allows you to distinguish between constructors which accept primitive int versus those which might accept the java.lang.Integer type. but to populate the object array of actual arguments to the reflective invocation, you should wrap primitives in their corresponding wrapper type, e.g. int --> java.lang.Integer, char --> java.lang.Character, and so forth.
good luck,
p

Reflection Class question

Hello,
I have an xml gallery and I am trying to add reflections to the images. Is there a way I can add the reflections to a loader? Or what do I have to do?
If I can't and I have to make a mc to do this I am not sure what to do. Can someone please help me?
Here is my current code:
import fl.transitions.Tween;
import fl.transitions.easing.*;
import com.pixelfumes.reflect.*;
var xmlRequest:URLRequest = new URLRequest("imageData.xml");
var xmlLoader:URLLoader = new URLLoader(xmlRequest);
var imgData:XML;
var imageLoader:Loader;
var rawImage:String;
var rawH:String;
var rawW:String;
var inTween:Tween
var outTween:Tween
var imgNum:Number = 0;
var checkSec:Timer = new Timer(100);
var numberOfChildren:Number;
var imageReflect:Reflect
xmlLoader.addEventListener(Event.COMPLETE, xmlLoadedF);
btnNext.addEventListener(MouseEvent.CLICK, nextImgF);
btnBack.addEventListener(MouseEvent.CLICK, prevImgF);
btnNext.buttonMode = true;
btnBack.buttonMode = true;
function xmlLoadedF (event:Event):void{
 checkSec.start();
 checkSec.addEventListener(TimerEvent.TIMER, checkerF);
 imgData = new XML(event.target.data);
function packagedF():void{
 checkSec.removeEventListener(TimerEvent.TIMER, checkerF);
 rawImage = imgData.image[imgNum].imgURL;
 numberOfChildren = imgData.*.length();
 rawW = imgData.image[imgNum].imgW;
 rawH = imgData.image[imgNum].imgH;
 imageLoader = new Loader;
 imageLoader.load(new URLRequest(rawImage));
 master_mc.addChild(imageLoader);
 imageLoader.x = (stage.stageWidth - Number(rawW)) /1.65;
 imageLoader.y = (stage.stageHeight - Number(rawH)) /5;
 inTween = new Tween(imageLoader, "x", Regular.easeInOut, 1500, (stage.stageWidth - Number(rawW)) /1.65, 1.5, true);
 imageLoader.scaleX = .8;
 imageLoader.scaleY = .8;
// this next line is the one that I am having a pickle over - where it says "??". I know its supposed to be mc but I am trying to not use mc.
imageReflect = new Reflect({??:imageLoader, alpha:50, ratio:50, distance:0, updateTime:0, reflectionDropoff:1});
function checkerF(event:TimerEvent):void {
if (imgNum == 0) {
packagedF();
}else if(imgNum < numberOfChildren) {
packagedF();
}else{
imgNum = 0;
packagedF();
function nextImgF(e:MouseEvent):void {
checkSec.addEventListener(TimerEvent.TIMER, checkerF);
outTween = new Tween(imageLoader, "x", Regular.easeInOut, (stage.stageWidth - Number(rawW)) /1.65, -1200, 1.5, true);
imgNum++;
function prevImgF(e:MouseEvent):void {
checkSec.addEventListener(TimerEvent.TIMER, checkerF);
outTween = new Tween(imageLoader, "x", Regular.easeInOut, -1200, (stage.stageWidth - Number(rawW)) /1.65, 1.5, true);
imgNum--;
Also the nextImageF works just fine but the prevImageF load both the previous image and the next - AT THE SAAAME TIME! What's up with that? - Do you know?
Thanks for any help!

Well, you could add a MovieClip that would host your Loader instance, and once loading is complete you could apply the refection to the host MovieClip.
Something like this:
var imageLoaderHost:MovieClip;
function packagedF():void{
checkSec.removeEventListener(TimerEvent.TIMER, checkerF);
rawImage = imgData.image[imgNum].imgURL;
numberOfChildren = imgData.*.length();
rawW = imgData.image[imgNum].imgW;
rawH = imgData.image[imgNum].imgH;
imageLoaderHost = new MovieClip();
imageLoader = new Loader;
imageLoader.contentLoaderInfo.addEventListener(Event.COMPLETE, loadCompleteHandler);
imageLoaderHost.addChild(imageLoader);
master_mc.addChild(imageLoaderHost);
imageLoader.load(new URLRequest(rawImage));
imageLoaderHost.x = (stage.stageWidth - Number(rawW)) /1.65;
imageLoaderHost.y = (stage.stageHeight - Number(rawH)) /5;
inTween = new Tween(imageLoaderHost, "x", Regular.easeInOut, 1500, (stage.stageWidth - Number(rawW)) /1.65, 1.5, true);
imageLoader.scaleX = .8;
imageLoader.scaleY = .8;
function loadCompleteHandler(event:Event)
imageLoader.contentLoaderInfo.removeEventListener(Event.COMPLETE, loadCompleteHandler);
imageReflect = new Reflect({mc:imageLoaderHost, alpha:50, ratio:50, distance:0, updateTime:0, reflectionDropoff:1});

Reflection - class and superclass fields

Hi,
I want to obtain all the fields in a class - private or public no metter if they are defined in the superclasses or the class itself.
Class.getFields() is said to return the public fields and Class.getDeclaredFields() returns the ones declared in the class.
Is there an easier way to get the fields of the class and its superclasses without using getSuperclass() recursively? Maybe I need the fields to be protected?
Thanks in advance
Mike

Thanks for the quick reply.
I will make further tests, and just wanted to know if there is a shorter way to get them.
Mike

Dynamic method call needs reflection class?

Hi,
First of all, this is my first post so go easy on me ;)
I would like to have something like this in Java:
String name = "number1";
int temp = name + getme();
the integer temp should now be the result of the method "number1getme()".
By changing the value of 'name' I could get the value of number2, number3 etc. etc.
Hope you understand and can help.
Yours Sincerely,
GrandiJoos

If you really want to do it this way, you will indeed need to use reflection. Have you considered other options, such as storing values in a Map or creating one getme() method that takes a name argument?Map<String, Integer> temps = new HashMap<String, Integer>();
.. fill the map with temperatures
String name="number1";
int temp = temps.get(name);orString name="number1";
public int getme(String name) {
int result = ...;
if(name.equals("number1")) {
result = <some temp here>;
return result;
}

Loading a class via reflection without knowing the full qualified path ?

Hi there
I d like to load a class via reflection and call the constructor of the class object. My problem is that I dont know the full qulified name e.g. org.xyz.Classname bur only the Classname.
I tried different things but none seem to work:
 1. Class c = Class.forName("Classname"); //does not suffice, full qualified name required
2. ClassLoader classloader = java.lang.ClassLoader.getSystemClassLoader();
 try {
 Class cl = classloader.loadClass(stripFileType(Filename));//if i do not pass the full qualified name i get a ClassNotFoundException
3. I tried to consruct a class object with my own classloader , calling:
 Class cl = super.defineClass(null, b, 0, b.length ); b is of type byte[]This almost works. I get a class Object without knowing the full qulified path. I can transform a filename into a raw array of bytes and I get the class out of it. But there is still a problem: If there are more than on classes defined in the same textfile I get an InvocationTargetException.
It looks like this:
package org.eml.adaptiveUI.demo;
import com.borland.jbcl.layout.*;
import java.awt.*;
import org.eml.adaptiveUI.layout.*;
import javax.swing.*;
import java.awt.event.*;
* Title: 
* Description: 
* Copyright: Copyright (c) 2003
* Company: 
* @author not attributable
* @version 1.0
public class twoButtons extends JFrame {
SPanel sPanel1 = new SPanel();
JButton jButton1 = new JButton();
GridBagLayout gridBagLayout1 = new GridBagLayout();
GridBagLayout gridBagLayout2 = new GridBagLayout();
public twoButtons() throws HeadlessException {
 try {
 jbInit();
 catch(Exception e) {
 e.printStackTrace();
public static void main(String args[]){
 twoButtons twob = new twoButtons();
 twob.pack();
 twob.show();
private void jbInit() throws Exception {
 this.getContentPane().setLayout(gridBagLayout1);
 jButton1.setText("button 1");
 jButton1.addActionListener(new TransformationDemo_jButton1_actionAdapter(this));
 this.getContentPane().add(sPanel1, new GridBagConstraints(0, 0, 1, 1, 1.0, 1.0
 ,GridBagConstraints.CENTER, GridBagConstraints.BOTH, new Insets(57, 52, 94, 108), 35, 44));
 sPanel1.add(jButton1, new GridBagConstraints(0, 0, 1, 1, 0.0, 0.0
 ,GridBagConstraints.CENTER, GridBagConstraints.NONE, new Insets(5, 41, 0, 0), 0, 0));
void jButton1_actionPerformed(ActionEvent e) {
 System.out.println("button 1 source: " + e.getSource());
 System.out.println("d: " + e.getID());
 System.out.println("/n commmand: " + e.getActionCommand());
class TransformationDemo_jButton1_actionAdapter implements java.awt.event.ActionListener {
twoButtons adaptee;
TransformationDemo_jButton1_actionAdapter(twoButtons adaptee) {
 this.adaptee = adaptee;
public void actionPerformed(ActionEvent e) {
 adaptee.jButton1_actionPerformed(e);
}As you can see there is the class TransformationDemo_jButton1_actionAdapter class defined in the same classfile. The problem is now that the twoButtons constructor calls the TransfomationDemo_jButton1_actionAdapter constructor and this leads to InvocationTargetException. I dont know if this is a java bug because it should be possible.
Can you help me?

hi thanks at first,
the thing you mentioned could be a problem, but I dont think it is.
If I have the full qualified name (which I havent) then everything goes normal. I only have to load the "twoButtons" class and not the other (actionadapter class), so I dont think this is the point. In this case the twoButtons constructor constructs an object of the actionadapter class and everything goes well. The bad thing is though that I do not have the full qulified name :(
Invocation target exception tells me (in own words): Tried to acces the constructor of the actionadapter class (which is not public) out of class reflectionTest class .
reflectionTest is the class where the reflection stuff happens and the twoButttons class is defineClass() ed.
The problem is, only twoButtons class has the rights to call methods from the actionadapter class, the reflection class does not. BUT: I do not call the actionadapter methods from the reflection class. I call them only from the twoButtons class.
I hope somebody understands my problem :)

Reflection on abstract classes

import java.lang.reflect.Method;
public class MethodInfoDemo {
 public static void printMethodInfo(final Object obj) {
 Class type = obj.getClass();
 final Method[] methods = type.getMethods();
 for (int idx = 0; idx < methods.length; idx++) {
 System.out.println(methods[idx]);
import javax.swing.AbstractAction;
public class ReflectScaf {
 public static void main(String args[]) {
 HtmlCreator h = new HtmlCreator();
 MethodInfoDemo.printMethodInfo(AbstractAction());
}Hello again, how do you do reflection on abstract classes?
Because I can't instantiate AbstractAction I can't feed an object to the getMethods() method in the reflection class.
Any ideas?

You don't need an instance of the class in order to do reflection. You just need the class' Class object.
import java.lang.reflect.*;
public abstract class AbstractReflection {
 public static void main(String[] args) throws Exception {
 Class klass = AbstractReflection.class; // or Class.forName("AbstractReflection")
 Method[] methods = klass.getMethods();
 for (Method m : methods) {
 System.out.println(m);
 public abstract int foo();
 public abstract void bar(String str);
 public void baz() {}
:; java -cp classes AbstractReflection
public static void AbstractReflection.main(java.lang.String[]) throws java.lang.Exception
public abstract int AbstractReflection.foo()
public abstract void AbstractReflection.bar(java.lang.String)
public void AbstractReflection.baz()
public native int java.lang.Object.hashCode()
public final native java.lang.Class java.lang.Object.getClass()
public final void java.lang.Object.wait() throws java.lang.InterruptedException
public final void java.lang.Object.wait(long,int) throws java.lang.InterruptedException
public final native void java.lang.Object.wait(long) throws java.lang.InterruptedException
public boolean java.lang.Object.equals(java.lang.Object)
public final native void java.lang.Object.notify()
public final native void java.lang.Object.notifyAll()
public java.lang.String java.lang.Object.toString()

Reflect the class that implements Runnable

Hi,
I am implementing the reflection of the class that implements Runnable. In order to start a new thread I am trying to invoke "start()" method ( which is obviously not defined my class ) and I therefore I am getting "java.lang.NoSuchMethodException".
I am wondering is it possible at all to start a new thread on a reflected class?
thanks in advance.
{ Class refClass = Class.forName(className);
String methodName = "start";
Class[] types = new Class[1];
types[0] = Class.forName("java.util.HashMap");
Constructor cons = refClass.getConstructor(types);
Object[] params = new Object[5];
params[0] = new HashMap();
Method libMethod = refClass.getMethod(methodName, null);
libMethod.invoke(objType, null); }

Well, if we knew what it meant to "start a thread on a class" we could probably figure out how to "start a thread on a reflected class". If we knew what a "reflected class" was, that is.
In other words, it would help if you rephrased your question using standard terminology (and also explained why you want to do whatever it is you want to do).
But let's guess for now: If you have an object which implements Runnable then you start a thread to run that object like this:
Runnable r = // some object which implements Runnable
new Thread(r).start();Not what you wanted? Go ahead and clarify then.

Reflection question: Creating dynamic array classes

I'm trying to create a String[].class dynamically by passing into a method the value "String[]" and then returning the Class, but I can't get my head around creating an array version.
e.g.
public Class classFromName(String className)
return Class.forName(className);
but it fails on arrays passed in. Fine for "String", but not "String[]" or "String[][]".
Is this possible?
Thanks
Mark Fisher ([email protected])

I couldn't get just "String" to work.
But remember that you usually write just "String" in source code because there's an implicit import java.lang.* statement at the beginning of your Java source code. That means that "java.lang.String" is the full name of the class. Imports apply onto to source code and are not "remembered" after the compilation process is finished.
If you want an array of Strings, the JVM name for that class is "[Ljava.lang.String;". I think there's also a way of getting the class object for array types in the reflection classes... I'll let you look for that in the API docs.

Problem with reflection in Generics

I'm using the Prototype compiler for JSR-014 and I am having a big problem with reflection. In the simplest case
class n<T> {
 void go() {
 this.getGenericType().getTypeParameters();
 this.getClass().getGenericInterfaces();
}I get a "cannot resolve symbol" on both lines. A glance at the jar included with the prototype shows why: all the collection classes are there, and a lot of the java.lang types, but not java.lang.Class and none of the java.lang.reflection classes.
So what gives? Is reflection not supported yet? (gaak!) Is there another jar I am supposed to download?
Thanks

Schapel is right.
but also
The signatures for fields and methods will include the generic types.
If you really wanted to, this would work.
get the Class's ClassLoader,
work out the name of the Class's file, and get an inputStream to this resource (from the classloader). (This bit works because I use as a diagnostics tool to see if classes are loaded from my jar, or my patches directory - see below).
Write some stuff to read the class file and parse out the generic signatures for the things you are interested in.
I don't think this last part would fit into anyones definition of "fun", however the specs are all available, and it may turn out simpler than at first appearances.
Here's the code I use to get the location of where a class is loaded from.
 static URL getLoadPath(Class theClass) {
 StringBuffer resourcename = new StringBuffer(theClass.getName());
 for(int i=0;i < resourcename.length(); i++) {
 if(resourcename.charAt(i) == '.') {
 resourcename.setCharAt(i,'/');
 resourcename.append(".class");
 return theClass.getClassLoader().getResource(resourcename.toString());
 }if you use getResourceAsStream() in place of getResource() you will have the .class file as an inputStream which you can read and parse.
Have Fun
Bruce

Java Reflection Help

Guys I have a string
vtEvents.byteArrayEventInterfaceHelper.getMetaObject().findDef("byteArrayEvent")
How do i create a reflection class for this and execute the above statement.

What's this dot-java stuff? Are you sending a source file? If so, that isn't going to work. You need to compile the file and send the dot-class file.
I'll try that. However, can I make the Client program complie the .java file? For example. something like Class2.compile()? Is this feature available, or do I have to open Class2.java and compile it from there?
And in the server you need to either store that somewhere in the server's classpath....
Isn't it automatically stored there? If not, how do I make it stored in the same file as the Server source file (I assume that's what you mean by classpath)?
Thanks for your help... !!!

Difference between "new classname()" and class.forName("...")?

Hi,
Please clarify me : What is the difference between the instnce creation by using new operator *( new ClassName())* and instance creation using class.forName("fully Qualified Name");
thanks
Gaurav

The compiler can tell you whether new ClassName() will be valid. For the other, you have to wait until runtime to know for sure.
new ClassName(...) can be invoked with arguments, and you provide them directly and simply. If you want to reflectively create an instance using a constructor that takes arguments, it's a more convoluted process.
Using new, you know which checked exceptions can be thrown and you catch them directly. Using reflection, you have to catch some other exception and unravel its cause.
You can use reflection (Class.forName and its more complicated cousins) when you don't know the classname at compile time.You can't do this with new.
Don't use reflection unless you have to. It's more complex, somewhat less performant, and it denies you certain compile time checks.

Constructor of package protected class

Why has class Test no constructor when trying to get the default constructor by reflection.
class Test {
     public static void main(String[] args){
          try {
               Class test=Test.class;
               Constructor[] ctor= test.getConstructors();
               System.out.println(ctor.length);
          } catch (Exception e) {
               e.printStackTrace();
}

Returns:
the array of Class objects representing all the
the declared members of this classWrong citation:
Returns an array containing Constructor objects reflecting all the public constructors of the class represented by this Class object. An array of length 0 is returned if the class has no public constructors, or if the class is an array class, or if the class reflects a primitive type or void.

Reflection class

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