Dynamic class casting.

Hi Friends,
How do I cast an object dynamically ?
Here I made a sample example for what I need exactly.
java.lang.String str = "sample";
java.lang.Object obj = str;
Class cls = obj.getClass();
java.lang.String tmpStr = (cls)obj; // this is an error.
Instead of casting like (java.lang.String), I wanted to replace "(java.lang.String)" with an variable.
Any ideas??
Thanks,
SK.

Doesn't make sense to me at all why you think you'd
need that. You already know you want it to be a
java.lang.String, because you coded:
java.lang.String tmpStr = (cls)obj;
Certainly you and the compiler have to know beforehand
the object type you need to cast to, so why the fuss?Hi,
I typed wrongly in my org. note. Sorry about that.
Actual code snippet looks like this.
java.lang.String str = "sample";
java.lang.Object obj = str;
Class cls = obj.getClass();
cls tmpStr = (cls)obj; // this is giving me an error.
I wanted to cast that field dynamically, because upfront I dont know the type of the object.
In the above example, just for the example sake, I selected a data type "String". Actually I need to cast it based on the type of the object at runtime.
Thanks,
SK.

Similar Messages

Can I do dynamic class cast with java SE1.4.2?

Hi,
I have some question on dynamic class cast.
I'm using java SE1.4.2. Suppose I have a method :
castObjectToSomething(Object o)
Something s = (Something) o;
However, I don't know what is the class to cast until runtime. How can I do a runtime class cast?
I know that java 5.0 have a Class.cast() method which java1.4.2 does not have. But can I do the same stuff by using SE1.4.2?
Thank You!!!!!
oh_silly

There is no sense in wanting to cast to a class that is only known at runtime. Because you can't do anything with such a class during runtime. Even though you could technically retrieve the class name, the method names and the parameter names, you could do nothing with this class as you don't know what it is doing. If you would know what it can do, you would know it also during compile time and then you would know the classname/interface name you want to cast to and can import it and use it reasonably.
Tell us the requirement that you think you have and we will proof you that you don't need such a requirement.

Dynamic class casting during runtime

I'm reading parameters for my application from the configuration file. Then in the code I should dynamically during the runtime make class cast:
(instead of having String in the code, I should cast the object to the class that was
defined in the configuration file.)
String tmp = (String) object;
Could somebody provide an example how can I do this? I have understood I could use reflection API for this problem.

I am not sure that I understand what you are asking correctly, but it might be something that bothered me some time ago.
My problem was that I wrote names of Classes (as Stings) into a file, and later wanted to be able to initialize a specific object of the class based on String names that were read from that file.(sorry if this is confusing).
I was programing a Chess simulator. All figures were subclasses of the class Figure, and were named Peon, Queen...)
I wanted to make a new Peon object, for every "Peon" String that was read from the file, and to make an new Queen object for every "Queen" in the file and so on.
I used something like this:
String objectName = in.readUTF(); //or some other way to get a String
Figure f = (Figure) Class.forName(objectName).newInstance(); Class.forName(String name) returns a object of class Class that represents all objects of type name.
And invoking .newInstance() gives you a new object of the class that is being represented by the object of class Class that you invoked .newInstance() on.
Sorry - migth be confusing again but i think it is correct.
This call to .newInstance() calls the default no-argument constructor...
There is no way to call a argument containing constructor with .newInstance()

Dynamic class cast and instanceof

I am looking for a way to dynamically test an object for being of a specific class. The instanceof operator can only be used with literally named classes I understand. So you cannot have something like boolean checkClass( Object o, Class c ) {
return o instanceof c;
} Is there any way to do something like this by use of the reflection API? The point is that instanceof only works statically, the reference type being tested for being specified at compile time. The question is whether it can be done with a reference type being specified at run-time, ie dynamically.

There is a collection of parameters of various types, which is passed to some client module.
There should be a, say 'checkParam' method for the client, which checks for existence of a certain parameter by its name, and also specified which class the parameter should have. So it should be called like
checkParam( params, "paramName", String.class )I wanted to avoid hard-coded types, but have the class specified as an argument to this method. I feel like there should be some way to accomplish that. What swingfreak intended may be a way.

Dynamic Class cast

I have an instance of a class as a generic Object and I want to
get all the methods and fields etc without resorting to too much
reflection.
Object o; //i have this
Class c = o.getClass();
c myobj = (c)o; //i want to do some casting and not go into getting declared
//fields and methods and then call them.
myObj.get(...); //get values from there
Is it possible or any other way?

No you can't do that. Basically your question is, can I use reflection without using reflection.

Dynamic class loading problem using unknown JAR archive and directory names

I read the following article, which enlightened me a lot:
Ted Neward: Understanding Class.forName().
However, it took me some while to understand that my problem is the other way around:
I know the name of the class, I know the name of the method,
but my program/JVM does not know where to load the classes from.
Shortly, my problem is that the server engine that I am writing
uses two different versions of the same library.
So I am trying out the following solution:
My program is named TestClassPathMain.java
Assume the two libraries are named JAR1.jar and JAR2.jar
and the class/instance method that should
be exposed to TestClassPathMain.java by them is named
TestClass1.testMethod().
As long as I was depending on just one library,
I put JAR1.jar in the classpath before starting java,
and I was happy for a while.
At the moment I got the need to use another version of
TestClass1.testMethod() packaged in JAR2.jar,
a call would always access JAR1.jar's
TestClass1.testMethod().
I then decided to remove JAR1.jar from the classpath,
and programmatically define two separate ClassLoaders, one for use
with JAR1.jar and the other for use with JAR2.jar.
However, the problem is only partly solved.
Please refer to the enclosed code for details.
(The code in the JAR1.jar/JAR2.jar is extremely simple,
it just tells (by hardcoding) the name of the jar it is packaged in
and instantiates another class packaged in the same jar using
the "new" operator and calls a method on it. I don't enclose it.)
The TestClassPathMain.java/UC1.java/UC2.java code suite was
successfully compiled with an arbitrary of JAR1 or JAR2 in the classpath,
however removed from the classpath at runtime.
(I know that this could have been done (more elegantly...?) by producing an Interface,
but I think the main problem principle is still untouched by this potential lack of elegancy(?))
1) This problem should not be unknown to you experts out there,
how is it generally and/or most elegantly solved?
The "*** UC2: Variant 2" is the solution I would like best, had it only worked.
2) And why arent "*** UC2: Variant 2" and
"*** static UC2: Variant 2" working,
while "*** Main: Variant 2" is?
3) And a mal-apropos:
Why can't I catch the NoClassDefFoundError?
The output:
*** Main: Variant 1 JAR 1 ***:
Entering TestClass1.testMethod() packaged in JAR1.jar
About to instantiate TestClass2 with the new operator
About to call TestClass2.testMethod()
Entering TestClass2.testMethod() packaged in JAR1.jar
*** Main: Variant 1 JAR 2 ***:
Entering TestClass1.testMethod() packaged in JAR2.jar
About to instantiate TestClass2 with the new operator
About to call TestClass2.testMethod()
Entering TestClass2.testMethod() packaged in JAR2.jar
*** Main: Variant 2 JAR 1 ***:
Entering TestClass1.testMethod() packaged in JAR1.jar
About to instantiate TestClass2 with the new operator
About to call TestClass2.testMethod()
Entering TestClass2.testMethod() packaged in JAR1.jar
*** Main: Variant 2 JAR 2 ***:
Entering TestClass1.testMethod() packaged in JAR2.jar
About to instantiate TestClass2 with the new operator
About to call TestClass2.testMethod()
Entering TestClass2.testMethod() packaged in JAR2.jar
*** UC1: Variant 1 JAR 1 ***:
Entering TestClass1.testMethod() packaged in JAR1.jar
About to instantiate TestClass2 with the new operator
About to call TestClass2.testMethod()
Entering TestClass2.testMethod() packaged in JAR1.jar
*** UC1: Variant 1 JAR 2 ***:
Entering TestClass1.testMethod() packaged in JAR2.jar
About to instantiate TestClass2 with the new operator
About to call TestClass2.testMethod()
Entering TestClass2.testMethod() packaged in JAR2.jar
*** static UC2: Variant 2 JAR 1 ***:
Exception in thread "main" java.lang.NoClassDefFoundError: TestClass1
        at UC2.runFromJarVariant2_static(UC2.java:56)
        at TestClassPathMain.main(TestClassPathMain.java:52)
TestClassPathMain.java
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
public class TestClassPathMain {
    public static void main(final String args[]) throws MalformedURLException, ClassNotFoundException, InstantiationException, SecurityException, NoSuchMethodException, IllegalArgumentException, IllegalAccessException, InvocationTargetException {
            // Commented out because I cannot catch the NoClassDefFoundError.
            // Why?
            try {
                final TestClass1 testClass1 = new TestClass1();
                System.out.println(
                    "\nThe class TestClass1 is of some unexplicable reason available." +
                    "\nFor the purpose of the test, it shouldn't have been!" +
                    "\nExiting");
                System.exit(1);
            } catch (NoClassDefFoundError e) {
                System.out.println("\nPositively confirmed that the class TestClass1 is not available:\n" + e);
                System.out.println("\n\nREADY FOR THE TEST: ...");
            // Works fine
            System.out.println("\n*** Main: Variant 1 JAR 1 ***:");
            runFromJarVariant1("file:/W:/java/eclipse/workspaces/simped_test/CP1/JAR1.jar");
            System.out.println("\n*** Main: Variant 1 JAR 2 ***:");
            runFromJarVariant1("file:/W:/java/eclipse/workspaces/simped_test/CP2/JAR2.jar");
            // Works fine
            System.out.println("\n*** Main: Variant 2 JAR 1 ***:");
            runFromJarVariant1("file:/W:/java/eclipse/workspaces/simped_test/CP1/JAR1.jar");
            System.out.println("\n*** Main: Variant 2 JAR 2 ***:");
            runFromJarVariant1("file:/W:/java/eclipse/workspaces/simped_test/CP2/JAR2.jar");
            // Works fine
            final UC1 uc1 = new UC1();
            System.out.println("\n*** UC1: Variant 1 JAR 1 ***:");
            uc1.runFromJarVariant1("file:/W:/java/eclipse/workspaces/simped_test/CP1/JAR1.jar");
            System.out.println("\n*** UC1: Variant 1 JAR 2 ***:");
            uc1.runFromJarVariant1("file:/W:/java/eclipse/workspaces/simped_test/CP2/JAR2.jar");
            // Crashes
            System.out.println("\n*** static UC2: Variant 2 JAR 1 ***:");
            UC2.runFromJarVariant2_static("file:/W:/java/eclipse/workspaces/simped_test/CP1/JAR1.jar");
            System.out.println("\n*** static UC2: Variant 2 JAR 2 ***:");
            UC2.runFromJarVariant2_static("file:/W:/java/eclipse/workspaces/simped_test/CP2/JAR2.jar");
            // Crashes
            final UC2 uc2 = new UC2();
            System.out.println("\n*** UC2: Variant 2 JAR 1 ***:");
            uc2.runFromJarVariant2("file:/W:/java/eclipse/workspaces/simped_test/CP1/JAR1.jar");
            System.out.println("\n*** UC2: Variant 2 JAR 2 ***:");
            uc2.runFromJarVariant2("file:/W:/java/eclipse/workspaces/simped_test/CP2/JAR2.jar");
    private static void runFromJarVariant1(final String jarFileURL)
        throws MalformedURLException,
               ClassNotFoundException,
               InstantiationException,
               IllegalArgumentException,
               IllegalAccessException,
               InvocationTargetException,
               SecurityException,
               NoSuchMethodException {
        final URL url = new URL(jarFileURL);
        final URLClassLoader cl =
            new URLClassLoader(new URL[]{url},
                               Thread.currentThread().getContextClassLoader());
        final Class clazz = cl.loadClass("TestClass1");
        final Object testClass1 = clazz.newInstance();
        final Method testMethod1 = clazz.getMethod("testMethod", null);
        testMethod1.invoke(testClass1, null);
    private static void runFromJarVariant2(final String jarFileURL)
        throws MalformedURLException,
               ClassNotFoundException,
               InstantiationException,
               IllegalArgumentException,
               IllegalAccessException,
               InvocationTargetException,
               SecurityException,
               NoSuchMethodException {
        final URL url = new URL(jarFileURL);
        final URLClassLoader cl =
            new URLClassLoader(new URL[]{url},
                               Thread.currentThread().getContextClassLoader());
        final Class clazz = cl.loadClass("TestClass1");
        final TestClass1 testClass1 = new TestClass1();
        testClass1.testMethod();
UC1.java
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
public class UC1 {
    public void runFromJarVariant1(final String jarFileURL)
        throws MalformedURLException,
               ClassNotFoundException,
               InstantiationException,
               IllegalArgumentException,
               IllegalAccessException,
               InvocationTargetException,
               SecurityException,
               NoSuchMethodException {
        final URL url = new URL(jarFileURL);
        final URLClassLoader cl =
            new URLClassLoader(new URL[]{url},
                               Thread.currentThread().getContextClassLoader());
        final Class clazz = cl.loadClass("TestClass1");
        final Object testClass1 = clazz.newInstance();
        final Method testMethod1 = clazz.getMethod("testMethod", null);
        testMethod1.invoke(testClass1, null);
UC2.java
import java.lang.reflect.InvocationTargetException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
public class UC2 {
    public void runFromJarVariant2(final String jarFileURL)
    throws MalformedURLException,
           ClassNotFoundException,
           InstantiationException,
           IllegalArgumentException,
           IllegalAccessException,
           InvocationTargetException,
           SecurityException,
           NoSuchMethodException {
        final URL url = new URL(jarFileURL);
        final URLClassLoader cl =
            new URLClassLoader(new URL[]{url},
                               Thread.currentThread().getContextClassLoader());
        final Class clazz = cl.loadClass("TestClass1");
        final TestClass1 testClass1 = new TestClass1();
        testClass1.testMethod();
     * Identic to the "runFromJarVariant2" method,
     * except that it is static
    public static void runFromJarVariant2_static(final String jarFileURL)
    throws MalformedURLException,
           ClassNotFoundException,
           InstantiationException,
           IllegalArgumentException,
           IllegalAccessException,
           InvocationTargetException,
           SecurityException,
           NoSuchMethodException {
        final URL url = new URL(jarFileURL);
        final URLClassLoader cl =
            new URLClassLoader(new URL[]{url},
                               Thread.currentThread().getContextClassLoader());
        final Class clazz = cl.loadClass("TestClass1");
        final TestClass1 testClass1 = new TestClass1();
        testClass1.testMethod();
}

2. i need to load the class to the same JVM (i.e. to
the same environment) of the current running
aplication, so that when the loaded class is run, it
would be able to invoke methods on it!!!
ClassLoader(s) do this. Try the URLClassLoader.
(I was talking about relatively esoteric "security"
issues when I mentioned the stuff about Class objects
"scope".) You might use the URLClassLoader kind of
like this.
Pseudo-code follows:
// setup the class loader
URL[] urls = new URL[1];
urls[0] = new URL("/path/to/dynamic/classes");
URLClassLoader ucl = new URLClassLoader(urls);
// load a class & use make an object with the default constructor
Object tmp = ucl.loadClass("dynamic.class.name").newInstance();
// Cast the object to a know interface so that you can use it.
// This may be used to further determine which interface to cast
// the class to. Or it may simply be the interface to which all
// dynamic classes have to conform in your program.
InterfaceImplementedByDynamicClass loadedObj =
    (InterfaceImplementedByDynamicClass)tmp;It's really not as hard as it sounds, just write a little test of
this and you will see how it works.

Dynamic Type casting

Can we dynamically type-cast an object reference passed to Object Clss to that specific class?
Here is what I want to do.
I am going to pass an object reference to a method, which has Object class as parameter to it, as shown below. Using getClass() or some other way, I want to dynamically typecast this reference to the original Class and call some method of this Class.
void test (Object ref1){
((ref1.getClass())ref1).writeLog();
By doing this, am I violating the basic Object Orineted rules?

I mean, consider an hypothetical case (which is wrong
from OO point of view) that there are suppose 10
classes in my system. None of them related to each
other, all are independent classes. But each one has a
method called, writeLog(). Now I want to write one
method which will be called by each of these classes
(in some 11th class), which will have "Object" as a
parameter. Now using the actual reference I want to
call the corresponding writeLog() method.
1 - Point out to management that the design is now officially broken.
2 - Point out that if the design is not fixed then any solution that impliments the changes will cost more to maintain in the future and will likely lead to instabilities in the system (due to complexity.)
3 - Implement one of the suggested solutions and make sure that you put in a lot of error checking and logging in the hacked solution.
4 - Produce extensive documentation about the impact of changing any of the objects that you are relying on. Push it to anyone and everyone that might ever touch or even suggest changes to the code.
Doing all of the above allows you to live stress free when the next revision breaks because someone didn't understand the implications of your hacked solution. You will be able to find the problem quickly and point out that it had nothing to do with your code but rather because someone else did not follow the complete documentation that you produced. And then when they complain that your solution was a hack you can point out that you explained that previously as well.

Dynamic class loading. *Problem*

Hi.
This is a strange one:
I'm compiling a java file dynamically and i try to load it using the current class loader. The usual way to do so is- this.getClass().getClassLoader() etc.
Now the strange part: the class loader is looking for the class file only in the class-path in which the java application was first run. There is no way to tell it to look in other directories, including the user current directory!
Changing the System properties of class path and library path do not help. The loader just remembers the initial class path and looks only there. It can't be told to look anywhere else!
Anyone has any idea how to make it look elsewhere ???? is it possible ???
Thanks!
Gil

2. i need to load the class to the same JVM (i.e. to
the same environment) of the current running
aplication, so that when the loaded class is run, it
would be able to invoke methods on it!!!
ClassLoader(s) do this. Try the URLClassLoader.
(I was talking about relatively esoteric "security"
issues when I mentioned the stuff about Class objects
"scope".) You might use the URLClassLoader kind of
like this.
Pseudo-code follows:
// setup the class loader
URL[] urls = new URL[1];
urls[0] = new URL("/path/to/dynamic/classes");
URLClassLoader ucl = new URLClassLoader(urls);
// load a class & use make an object with the default constructor
Object tmp = ucl.loadClass("dynamic.class.name").newInstance();
// Cast the object to a know interface so that you can use it.
// This may be used to further determine which interface to cast
// the class to. Or it may simply be the interface to which all
// dynamic classes have to conform in your program.
InterfaceImplementedByDynamicClass loadedObj =
(InterfaceImplementedByDynamicClass)tmp;It's really not as hard as it sounds, just write a little test of
this and you will see how it works.

Oracle Arrays and getVendorConnection API and Class Cast Exception

I 've gone through various threads relating to the topic of Oracle Arrays and the getVendorConnecton API call to avoid the class Cast Exception.. i ve used all these but am still facing the problem...
I would appreciate it if some one could resolve the following queries :
I am using Weblogic 8.1 SP5 with oracle 8i
1. I read that the need to use the getVendorConnection API to make pl/sql proc calls with oracle arrays from the WL Server wont be required to avoid classCastException...
I tried to use the connection from the WL connection pool ..but it didnot work....I used the getVendorConnection API ..which also doesnot seem to work..
I got the Heurisitc Hazard exception...I used the Oracle 9i driver ie ojdbc14.jar ...after this the exception is not coming but still the code doesnt seem to work...
the snippet of the code is pasted below :
~~~~~~~~~~~~~~~~~~~~~~~code is : ~~~~~~~~~~~~~~~~~~~
/*below :
logicalCon is the Connection from the WL connection pool
JDBCcon is the JDBC connection. */
<div> try </div>
<div>{ </div>
<div>
<b>vendorConn</b> = ((WLConnection)logicalCon).getVendorConnection();
</div>
<div>
//Calling the procedure
</div>
<div>
//java.util.Map childMap1 = JDBCcon.getTypeMap();
</div>
<div>
java.util.Map childMap1 = <b>vendorConn</b>.getTypeMap();
</div>
<div>
childMap1.put("SST_ROUTE_ENTRY", Class.forName("svm.stport.ejb.StaticRouteEntry"));
</div>
<div>
//JDBCcon.setTypeMap(childMap1);
<b>vendorConn</b>.setTypeMap(childMap1);
</div>
<div>
// Create an oracle.sql.ARRAY object to hold the values
</div>
<div>
/*oracle.sql.ArrayDescriptor arrayDesc1 = oracle.sql.ArrayDescriptor.createDescriptor("SST_ROUTE_ENTRY_ARR", JDBCcon); */
</div>
<div>
oracle.sql.ArrayDescriptor arrayDesc1 =
oracle.sql.ArrayDescriptor.createDescriptor("SST_ROUTE_ENTRY_ARR", <b>vendorConn</b>); // here if i use the JDBCcon it works perfectly.... <u>^%^%^%</u>
</div>
<div>
code to fill in the sst route entry array....
.....arrayValues1 */
</div>
<div>
/* oracle.sql.ARRAY array1 = new oracle.sql.ARRAY(arrayDesc1, JDBCcon, arrayValues1); */
</div>
<div>
oracle.sql.ARRAY array1 = new oracle.sql.ARRAY(arrayDesc1, <b>vendorConn</b>, arrayValues1);
</div>
<div>
callStatement = logicalCon.prepareCall( "? = call procName(?, ?, ?)");
</div>
<div>
/* ..code to set the ?s ie array1 */
</div>
<div>
callStatement.execute();
</div>
<div>
}catch(Exceptio e){
</div>
<div>
}</div>
<div>
finally </div>
</div>{</div>
<div>System.out.println(" I ve come to finally"); </div>
<div>}</div>
<div>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~code snippet ends here ~~~~~~~~~~~~~~``
</div>
I have observed that the control immediately comes to the finally block after the call to the createDescriptor line above with <u>^%^%^%</u> in the comment. If i use the JDBCCon in this line...it works perfectly fine.
Any pointers to where anything is getting wrong.
I have jst set the vendorCon to null in the end of the file and not closed it. Subsequently i have closed the logicalCon. This has been mentioned in some of the thread in this forum also.
Thanks,
-jw

Jatinder Wadhwa wrote:
I 've gone through various threads relating to the topic of Oracle Arrays and the getVendorConnecton API call to avoid the class Cast Exception.. i ve used all these but am still facing the problem...
I would appreciate it if some one could resolve the following queries :
I am using Weblogic 8.1 SP5 with oracle 8i
1. I read that the need to use the getVendorConnection API to make pl/sql proc calls with oracle arrays from the WL Server wont be required to avoid classCastException...
I tried to use the connection from the WL connection pool ..but it didnot work....I used the getVendorConnection API ..which also doesnot seem to work..
I got the Heurisitc Hazard exception...I used the Oracle 9i driver ie ojdbc14.jar ...after this the exception is not coming but still the code doesnt seem to work...
the snippet of the code is pasted below :
~~~~~~~~~~~~~~~~~~~~~~~code is : ~~~~~~~~~~~~~~~~~~~Hi. Show me the whole exception and stacktrace if you do:
try
vendorConn = ((WLConnection)logicalCon).getVendorConnection();
java.util.Map childMap1 = vendorConn.getTypeMap();
childMap1.put("SST_ROUTE_ENTRY" Class.forName("svm.stport.ejb.StaticRouteEntry"));
vendorConn.setTypeMap(childMap1);
oracle.sql.ArrayDescriptor arrayDesc1 =
oracle.sql.ArrayDescriptor.createDescriptor("SST_ROUTE_ENTRY_ARR",
vendorConn);
oracle.sql.ARRAY array1 = new oracle.sql.ARRAY(arrayDesc1, vendorConn, arrayValues1);
callStatement = logicalCon.prepareCall( "? = call procName(? ? ?)");
callStatement.execute();
}catch(Exception e){
e.printStackTrace();
finally
try{logicalCon.close();}catch(Exception ignore){}
System.out.println(" I ve come to finally");
/*below :
logicalCon is the Connection from the WL connection pool
JDBCcon is the JDBC connection. */
<div> try </div>
<div>{ </div>
<div>
<b>vendorConn</b> = ((WLConnection)logicalCon).getVendorConnection();
</div>
<div>
//Calling the procedure
</div>
<div>
//java.util.Map childMap1 = JDBCcon.getTypeMap();
</div>
<div>
java.util.Map childMap1 = <b>vendorConn</b>.getTypeMap();
</div>
<div>
childMap1.put("SST_ROUTE_ENTRY", Class.forName("svm.stport.ejb.StaticRouteEntry"));
</div>
<div>
//JDBCcon.setTypeMap(childMap1);
<b>vendorConn</b>.setTypeMap(childMap1);
</div>
<div>
// Create an oracle.sql.ARRAY object to hold the values
</div>
<div>
/*oracle.sql.ArrayDescriptor arrayDesc1 = oracle.sql.ArrayDescriptor.createDescriptor("SST_ROUTE_ENTRY_ARR", JDBCcon); */
</div>
<div>
oracle.sql.ArrayDescriptor arrayDesc1 =
oracle.sql.ArrayDescriptor.createDescriptor("SST_ROUTE_ENTRY_ARR", <b>vendorConn</b>); // here if i use the JDBCcon it works perfectly.... <u>^%^%^%</u>
</div>
<div>
code to fill in the sst route entry array....
.....arrayValues1 */
</div>
<div>
/* oracle.sql.ARRAY array1 = new oracle.sql.ARRAY(arrayDesc1, JDBCcon, arrayValues1); */
</div>
<div>
oracle.sql.ARRAY array1 = new oracle.sql.ARRAY(arrayDesc1, <b>vendorConn</b>, arrayValues1);
</div>
<div>
callStatement = logicalCon.prepareCall( "? = call procName(?, ?, ?)");
</div>
<div>
/* ..code to set the ?s ie array1 */
</div>
<div>
callStatement.execute();
</div>
<div>
}catch(Exceptio e){
</div>
<div>
}</div>
<div>
finally </div>
</div>{</div>
<div>System.out.println(" I ve come to finally"); </div>
<div>}</div>
<div>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~code snippet ends here ~~~~~~~~~~~~~~``
</div>
I have observed that the control immediately comes to the finally block after the call to the createDescriptor line above with <u>^%^%^%</u> in the comment. If i use the JDBCCon in this line...it works perfectly fine.
Any pointers to where anything is getting wrong.
I have jst set the vendorCon to null in the end of the file and not closed it. Subsequently i have closed the logicalCon. This has been mentioned in some of the thread in this forum also.
Thanks,
-jw

'Class Cast Exception' while invoking a EJB from a Servlet

          Hi,
          I am working on J2EE applications.I am using Webgain studio and weblogic server.I
          got a problem while invoking EJB from the servlet.
          While calling an EJB from the servlet, it is giving that "Class Cast Exception".This
          is because, the remote home reference is not able to type casted to the"Home Interface"
          of the EJB, even if I type casted explicitly. It is creating the context and able
          to identify the EJB with the JNDI name.
          Could please help me in solving this problem.I am pasting the code here.
          Thanks in advance,
          Dharma
          public void doGet(HttpServletRequest req, HttpServletResponse resp)
               throws ServletException, IOException
                    resp.setContentType("text/html");
                    PrintWriter out = new PrintWriter(resp.getOutputStream());
          try
          Context context=getInitialContext();
          Object reference=context.lookup("ArlProjContractorAppletSession");
          ArlProjContractorAppletSessionHome home=(ArlProjContractorAppletSessionHome)PortableRemoteObject.narrow(reference,ArlProjContractorAppletSessionHome.class);
          //Exception is occuring in the above statement. It is unable
          //to cast to the home interface
                    ArlProjContractorAppletSession the_ejb=null;
          try
          the_ejb=home.create();
          System.out.println("the_ejb = " + the_ejb.toString());
          catch(Exception e)
          e.printStackTrace();
          catch(Exception e)
          e.printStackTrace();
                    // to do: code goes here.
                    out.println("<HTML>");
                    out.println("<HEAD><TITLE>Contractor TimeTracker</TITLE></HEAD>");
                    out.println("<BODY>");
                    // to do: your HTML goes here.
                    out.println("</BODY>");
                    out.println("</HTML>");
                    out.close();


          I came across this kind of problem once. My problem went away after I upgraded
          from 5.1 SP6 to 5.1 SP8.
          "Dharma" <[email protected]> wrote:
          >
          >Hi,
          >
          >I am working on J2EE applications.I am using Webgain studio and weblogic
          >server.I
          >got a problem while invoking EJB from the servlet.
          >
          >While calling an EJB from the servlet, it is giving that "Class Cast
          >Exception".This
          >is because, the remote home reference is not able to type casted to the"Home
          >Interface"
          >of the EJB, even if I type casted explicitly. It is creating the context
          >and able
          >to identify the EJB with the JNDI name.
          >
          >Could please help me in solving this problem.I am pasting the code here.
          >
          >Thanks in advance,
          >Dharma
          >
          >
          >public void doGet(HttpServletRequest req, HttpServletResponse resp)
          >     throws ServletException, IOException
          >     {
          >          resp.setContentType("text/html");
          >          PrintWriter out = new PrintWriter(resp.getOutputStream());
          >
          > try
          > {
          >
          > Context context=getInitialContext();
          >
          > Object reference=context.lookup("ArlProjContractorAppletSession");
          >
          > ArlProjContractorAppletSessionHome home=(ArlProjContractorAppletSessionHome)PortableRemoteObject.narrow(reference,ArlProjContractorAppletSessionHome.class);
          >
          >//Exception is occuring in the above statement. It is unable
          >//to cast to the home interface
          >
          >          ArlProjContractorAppletSession the_ejb=null;
          >
          > try
          > {
          > the_ejb=home.create();
          >
          > System.out.println("the_ejb = " + the_ejb.toString());
          >
          > }
          > catch(Exception e)
          > {
          > e.printStackTrace();
          > }
          > }
          > catch(Exception e)
          > {
          > e.printStackTrace();
          > }
          >          // to do: code goes here.
          >
          >          out.println("<HTML>");
          >          out.println("<HEAD><TITLE>Contractor TimeTracker</TITLE></HEAD>");
          >          out.println("<BODY>");
          >
          >          // to do: your HTML goes here.
          >
          >          out.println("</BODY>");
          >          out.println("</HTML>");
          >          out.close();
          >     }
          >
          >
          >
          >
          >

View Criteria in ADF Query Panel with Table-Class Cast Exception

Hi,
I am getting Class Cast Exception when using view criteria for ADF Query Panel with Table. The version I am using is 11g Release 1(11.1.1.2.0)
Here is what I did:
1. created a view criteria on a view object
2. all are optional
3. all are Strings
3. Dragged the view criteria as a query component (ADF Query panel with Query table) on to the design layout
and the error when I clicked the Search button is:
javax.el.ELException: java.lang.ClassCastException: oracle.jbo.common.ViewCriteriaImpl cannot be cast to oracle.jbo.ViewCriteriaRow
at com.sun.el.parser.AstValue.invoke(AstValue.java:161)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:283)
at org.apache.myfaces.trinidad.component.UIXComponentBase.broadcastToMethodExpression(UIXComponentBase.java:1289)
at oracle.adf.view.rich.component.UIXQuery.broadcast(UIXQuery.java:115)
at oracle.adf.view.rich.component.fragment.UIXRegion.broadcast(UIXRegion.java:148)
at oracle.adf.view.rich.component.fragment.UIXRegion.broadcast(UIXRegion.java:148)
at oracle.adfinternal.view.faces.lifecycle.LifecycleImpl.broadcastEvents(LifecycleImpl.java:812)
at oracle.adfinternal.view.faces.lifecycle.LifecycleImpl._executePhase(LifecycleImpl.java:292)
at oracle.adfinternal.view.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:177)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:265)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:292)
at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at oracle.adf.model.servlet.ADFBindingFilter.doFilter(ADFBindingFilter.java:191)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at sni.foundation.facesextensions.filters.FoundationFilter.doFilter(FoundationFilter.java:92)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at oracle.adfinternal.view.faces.webapp.rich.RegistrationFilter.doFilter(RegistrationFilter.java:97)
at org.apache.myfaces.trinidadinternal.webapp.TrinidadFilterImpl$FilterListChain.doFilter(TrinidadFilterImpl.java:420)
at oracle.adfinternal.view.faces.activedata.AdsFilter.doFilter(AdsFilter.java:60)
at org.apache.myfaces.trinidadinternal.webapp.TrinidadFilterImpl$FilterListChain.doFilter(TrinidadFilterImpl.java:420)
at org.apache.myfaces.trinidadinternal.webapp.TrinidadFilterImpl._doFilterImpl(TrinidadFilterImpl.java:247)
at org.apache.myfaces.trinidadinternal.webapp.TrinidadFilterImpl.doFilter(TrinidadFilterImpl.java:157)
at org.apache.myfaces.trinidad.webapp.TrinidadFilter.doFilter(TrinidadFilter.java:92)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at oracle.security.jps.ee.http.JpsAbsFilter$1.run(JpsAbsFilter.java:94)
at java.security.AccessController.doPrivileged(Native Method)
at oracle.security.jps.util.JpsSubject.doAsPrivileged(JpsSubject.java:313)
at oracle.security.jps.ee.util.JpsPlatformUtil.runJaasMode(JpsPlatformUtil.java:413)
at oracle.security.jps.ee.http.JpsAbsFilter.doFilter(JpsAbsFilter.java:138)
at oracle.security.jps.ee.http.JpsFilter.doFilter(JpsFilter.java:70)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at oracle.dms.wls.DMSServletFilter.doFilter(DMSServletFilter.java:326)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at weblogic.servlet.internal.RequestEventsFilter.doFilter(RequestEventsFilter.java:27)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3592)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:121)
at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2202)
at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2108)
at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1432)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:201)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:173)
Caused by: java.lang.ClassCastException: oracle.jbo.common.ViewCriteriaImpl cannot be cast to oracle.jbo.ViewCriteriaRow
at oracle.adfinternal.view.faces.model.binding.FacesCtrlSearchBinding._clearFilterCriteriaRows(FacesCtrlSearchBinding.java:4549)
at oracle.adfinternal.view.faces.model.binding.FacesCtrlSearchBinding._addFilterCriteria(FacesCtrlSearchBinding.java:4603)
at oracle.adfinternal.view.faces.model.binding.FacesCtrlSearchBinding.processQuery(FacesCtrlSearchBinding.java:423)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.sun.el.parser.AstValue.invoke(AstValue.java:157)
Thanks
Venkatesh

Hi Frank.
I'm using JDev 11.1.1.3.0 as you suggest the error is no longer present in the latest version.
I can pick my query from the "Saved Search" pick list on the QueryPanel list of queries just fine, and it sets up the filter properly, but when I press the "Search" button, I get the same reported error...
<RegistrationConfigurator><handleError> Server Exception during PPR, #1
javax.el.ELException: java.lang.ClassCastException: oracle.jbo.common.ViewCriteriaImpl cannot be cast to oracle.jbo.ViewCriteriaRow
     at com.sun.el.parser.AstValue.invoke(AstValue.java:161)
     at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:283)
     at org.apache.myfaces.trinidad.component.UIXComponentBase.broadcastToMethodExpression(UIXComponentBase.java:1303)
     at oracle.adf.view.rich.component.UIXQuery.broadcast(UIXQuery.java:115)
     at oracle.adfinternal.view.faces.lifecycle.LifecycleImpl.broadcastEvents(LifecycleImpl.java:812)
     at oracle.adfinternal.view.faces.lifecycle.LifecycleImpl._executePhase(LifecycleImpl.java:292)
     at oracle.adfinternal.view.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:177)
     at javax.faces.webapp.FacesServlet.service(FacesServlet.java:265)
     at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
     at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
     at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:300)
     at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26)
     at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
     at oracle.adf.model.servlet.ADFBindingFilter.doFilter(ADFBindingFilter.java:191)
     at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
     at oracle.adfinternal.view.faces.webapp.rich.RegistrationFilter.doFilter(RegistrationFilter.java:97)
     at org.apache.myfaces.trinidadinternal.webapp.TrinidadFilterImpl$FilterListChain.doFilter(TrinidadFilterImpl.java:420)
     at oracle.adfinternal.view.faces.activedata.AdsFilter.doFilter(AdsFilter.java:60)
     at org.apache.myfaces.trinidadinternal.webapp.TrinidadFilterImpl$FilterListChain.doFilter(TrinidadFilterImpl.java:420)
     at org.apache.myfaces.trinidadinternal.webapp.TrinidadFilterImpl._doFilterImpl(TrinidadFilterImpl.java:247)
     at org.apache.myfaces.trinidadinternal.webapp.TrinidadFilterImpl.doFilter(TrinidadFilterImpl.java:157)
     at org.apache.myfaces.trinidad.webapp.TrinidadFilter.doFilter(TrinidadFilter.java:92)
     at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
     at oracle.security.jps.ee.http.JpsAbsFilter$1.run(JpsAbsFilter.java:94)
     at java.security.AccessController.doPrivileged(Native Method)
     at oracle.security.jps.util.JpsSubject.doAsPrivileged(JpsSubject.java:313)
     at oracle.security.jps.ee.util.JpsPlatformUtil.runJaasMode(JpsPlatformUtil.java:414)
     at oracle.security.jps.ee.http.JpsAbsFilter.doFilter(JpsAbsFilter.java:138)
     at oracle.security.jps.ee.http.JpsFilter.doFilter(JpsFilter.java:71)
     at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
     at oracle.dms.wls.DMSServletFilter.doFilter(DMSServletFilter.java:330)
     at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
     at weblogic.servlet.internal.RequestEventsFilter.doFilter(RequestEventsFilter.java:27)
     at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
     at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.doIt(WebAppServletContext.java:3684)
     at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3650)
     at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
     at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:121)
     at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2268)
     at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2174)
     at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1446)
     at weblogic.work.ExecuteThread.execute(ExecuteThread.java:201)
     at weblogic.work.ExecuteThread.run(ExecuteThread.java:173)
Caused by: java.lang.ClassCastException: oracle.jbo.common.ViewCriteriaImpl cannot be cast to oracle.jbo.ViewCriteriaRow
     at oracle.adfinternal.view.faces.model.binding.FacesCtrlSearchBinding._clearFilterCriteriaRows(FacesCtrlSearchBinding.java:4588)
     at oracle.adfinternal.view.faces.model.binding.FacesCtrlSearchBinding._addFilterCriteria(FacesCtrlSearchBinding.java:4642)
     at oracle.adfinternal.view.faces.model.binding.FacesCtrlSearchBinding.processQuery(FacesCtrlSearchBinding.java:424)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     at java.lang.reflect.Method.invoke(Method.java:597)
     at com.sun.el.parser.AstValue.invoke(AstValue.java:157)
     ... 42 more

Class Cast Exception in a custom adapter processing module

Hi,
I am trying to create a Custom adapter module in my file adapter as a Local enterprise Bean.
I have taken the "ConvertCRLFfromToLF" sample given by SAP as a reference, created an EJB module project, and deployed the enterprise archive to the J2EE engine.
However, i am getting a Class Cast Exception in the Adapter Engine for my communication channel.
Any help on this will much appreciated.
Thanks & Regards,
Renjith.

HI,
Managed to solve this..this was due to the additional jars which was included by the Developer Studio in the EAR file. We have to remoce the jars from the EAR, change the application.xml and sap_manifest.mf files to give reference to the jars already deployed in the J2EE engine.
Thanks & Regards,
Renjith

GET SET function in a dynamic Class?

Is it possible to add a GET SET function in a dynamic class, like we can add properties to a dynamic class?

correction :
MyObjectProxy extends ObjectProxy{
override callProperty(
// your dyna logic
and expose new MyObjectProxy(dynaInstance)

Difference between narrow() method usage and simple class cast for EJB

Hi,
I have a very simple question:
what is the difference between PortableRemoteObject.narrow(fromObj,
toClass) method usage and simple class cast for EJB.
For example,
1)
EJBObject ejbObj;
// somewhere in the code the home.create() called for bean ...
ABean a = (ABean)PortableRemoteObject.narrow(ejbObj,ABean.class);
OR
2)
EJBObject bean;
// somewhere in the code the home.create() called for bean ...
ABean a = (ABean)ejbObj;
Which one is better?
P.S. I'm working with WL 6.1 sp2
Any help would be appreciated.
Thanks in advance,
Orly

[email protected] (Orly) writes:
Hi,
I have a very simple question:
what is the difference between PortableRemoteObject.narrow(fromObj,
toClass) method usage and simple class cast for EJB.
For example,
1)
EJBObject ejbObj;
// somewhere in the code the home.create() called for bean ...
ABean a = (ABean)PortableRemoteObject.narrow(ejbObj,ABean.class);
OR
2)
EJBObject bean;
// somewhere in the code the home.create() called for bean ...
ABean a = (ABean)ejbObj;
Which one is better?(1) is mandated by the spec. It is required because CORBA systems may
not have sufficient type information available to do a simple case.
P.S. I'm working with WL 6.1 sp2 You should always use PRO.narrow()
andy

Class Cast Exception

Hi
I got class cast exception here
String value = String.valueOf
(((IPrivateMaterialApplicationView.IMaterial_InputElement)(wdContext.nodeMaterial_Input().nodeT_Matno_in().getElementAt(i))).getMatnr());
valueSet.put(value,value);
Thanks & Regards
Ravi Shankar B

Ravi,
the cause of this issue is that
wdContext.nodeMaterial_Input().nodeT_Matno_in().getElementAt(i)
does not return an instance of type
IPrivateMaterialApplicationView.IMaterial_InputElement
Check what type is returned by this method (in NWDS place your cursor over the method and the return type is displayed) and cast to that type.
Regards
Sebastian

Dynamic class casting.

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