Doubt in classes

hi
please check the code
data: lr_columns type ref to cl_salv_columns_tree.
data: gr_tree type ref to cl_salv_tree.
lr_columns = gr_tree->get_columns( ).
can any body explain wt lr_columns contains.
hw can i use tghis lr_columns
thanks& Regards
Spandna

Hi,
while creating an instance for a class we need to define a data type for that particular object,here in ABAP we define data type as type ref and class name for which we want to create instance.
Reward with Points if useful.

Similar Messages

Data Class in ABAP dictionary

hi,
recently we moved the tables from tablespace PSAPBTAD to user defined tablespace & since than we have poor performance in PROD - have any one had this issue before ? any idea on data class and tablespace ?
thanks

I doubt data class affects performance. It definitely affect upgrades and support packs so you'll want to confirm that every table you reorged is assigned the data class associated with its current tablespace, otherwise you can lose data.
It could be a lot of things affecting the performance. Maybe the reorg tool added too many small extents to the tables which is a problem only if you're not on SAN and if the tablespaces are DTMS. But I'd start with disk stats. Take a look and see if you've got hot spots, it's the first thing I'd check.
Oh, and how about database statistics, did you re-calc after the reorgs? It's essential.

Why class defination and class implementaion separated in abap?

hai experts,
i hav doubt why class defination and class implementaion separated in abap. In know in C++ its possible
but in JAVA its not possible . what is the main reson behind this concept in ABAP.
thanks in adv.

Hi Sree,
As far as I feel, it's been done with a view of readability. As you know that ABAP is very well modularized and organized programing language. When you define a local ABAP Class, you define two seperate sections of it. You define the Class Definition and then you define the Implementations. This way you can really have a look at all the class definitions which are organized in the same section. Then you can have a look at the selected implementation.
But if this hasn't been the scenario, then as developer looking at the complex classes would have made life hell for you. You can very well figure it out how good to keep things organized for later class maintainance and readability.
Hope this would shed some light on your question.
Thanks,
Samantak.

Classes, Stateful EJBs and EJB Container

Hi,
We have several doubts about classes, servlets, and EJBs.
We have been told that the instance of non-static classes from JSPs or servlets
can be a problem if we have a big number of clients connecting to weblogic (or
any other app server). Would it be a problem? Is it a better practice to instantiate
those classes from EJBs?
We have been told that EJBs are managed by the EJB container, and it uses a pool
for serving them to clients, passivating and activating them. This would include
the classes instantiated inside them. Is it true?
If all our guesses are true, the better way to implement a search with pagination
would be a stateful EJB, using handlers to save it in the client's session. But
we've heard that stateful EJBs are really bad for server's perfomance. Is it true?
We are using Weblogic 7.0. If so, what are they useful for???
If they can be a problem, how to build that searching using stateless EJBs?
Best regards,
Ignacio Sanchez

You're right, the concrete tag to use seems to be:
<replication-type>InMemory</replication-type>
Anyway, do you have any further explanation on Stateful's behaviour with many
clients and pagination implementation?
"Stanley Beamish" <[email protected]> wrote:
>
"Ignacio Sanchez" <[email protected]> wrote in message
news:[email protected]...
Thanks for your replies.
Anyway, I still have some questions about stateful EJBs. In a clusteredenvironment,
we've been told that stateful EJBs are only balanced before create()method. So,
if we have already "created" the Remote interface, we're using it,and the
server
fails and must be balanced to another instance, what will happen? Willwe
lost
that Remote interface and data included in it?
Not necessarily, you can enable replication, which means that your stateful
EJB's state (values of i-vars) can be replicated across nodes in a cluster.
Search through the WLS cluster documentation for details.
SB
And about your suggestion on pagination using stateless. Could youplease
explain
it in more detail? I haven't understood it well.
Thank you very much for your attention.
"Sri" <[email protected]> wrote:
Hi,
Look below for my coments.
S
"Ignacio Sanchez" <[email protected]> wrote:
Hi,
We have several doubts about classes, servlets, and EJBs.
We have been told that the instance of non-static classes from JSPsor
servlets
can be a problem if we have a big number of clients connecting to
weblogic
(or
any other app server). Would it be a problem? Is it a better practice
to instantiate
those classes from EJBs?It all boils down to your architecture. If you have a lot of clients
connecting
to web container then and if each client needs objects stored in session
then
you have to refactor your object distribution. But this could be avoided
by separating
static content from dynamic content (using proxies, load balancersetc),
having
more web containers etc. It's not necessary to instantiate these classes
in EJBs
always (then you are increasing your memory footprint). The generalguidelne
is
to do more heavy duty work as you go deeper into tiers hopefully handling
less
connections etc.
We have been told that EJBs are managed by the EJB container, and
it
uses a pool
for serving them to clients, passivating and activating them. Thiswould
include
the classes instantiated inside them. Is it true?
True.
If all our guesses are true, the better way to implement a search
with
pagination
would be a stateful EJB, using handlers to save it in the client'ssession.
But
we've heard that stateful EJBs are really bad for server's perfomance.
Is it true?
We are using Weblogic 7.0. If so, what are they useful for???
True if misused as stateful EJBs, just like HTTP sessions could bereplicated
and could be activated/passivated.
If they can be a problem, how to build that searching using stateless
EJBs?
You could cache searchs and pass identity and page numbers to theSLSB.
Best regards,
Ignacio Sanchez

ALV TREE DOUBT

Hi frnds,
i was going thru "BCALV_TREE_SIMPLE_DEMO", i got a doubt that
" class cl_gui_column_tree definition load.
class cl_gui_cfw definition load."
what is the purpose of "load" and can anyone please explain me the flow of
"BCALV_TREE_SIMPLE_DEMO" program.
Thanking u all.
satya

when u write LOAD statement before any object name....u can declare the objects of the predefined classes..
load cl_gui_alv_tree definition.
points please...

Regarding HTMLB button

Hello SDN
I'm new to portal and facing problem with button event management .when i triggered event its giving error that eventhandler could not be found .Where should i write my event handler in"doProcessAfterInput()" or elsewhere
waiting for help

HI,
I hope this code clears your doubt
public class HelloDyn extends PageProcessorComponent {
public DynPage getPage(){
    return new HelloDynDynPage();
public static class HelloDynDynPage extends JSPDynPage{
    public int state = 0;
    public void doInitialization(){
    public void doProcessAfterInput() throws PageException {
     public void confirm(Event event) {
          IPortalComponentResponse response=(IPortalComponentResponse)this.getResponse();
          IPortalComponentRequest request =(IPortalComponentRequest)this.getRequest();
          InputField inputf=(InputField)getComponentByName("name");
          String inputValue=inputf.getValueAsDataType().toString();
          response.write("Welcome" + " "+inputValue);
          IUser user1 = request.getUser();
          String usn = user1.getDisplayName();
          response.write(usn);
          state = 1;
    public void doProcessBeforeOutput() throws PageException {
         switch(state)
              case 0:
               this.setJspName("HelloJsp.jsp");
               break;
               case 1:
               this.setJspName("hiUser.jsp");
               break;

Use Of Interface(Memory Consume)

I have a doubt
//Interface A
code:
interface A{
public void add();
public void sub();
public void multiplication();
//Class B that Implements A
class B implements A{
public void add(){
int a=30;
int b=40;
int c=a+b;
System.out.println("The result of Addition is:-"c);
public void sub(){
int a=80;
int b=40;
int c=a-b;
System.out.println("The result of Substraction is:-"c);
public void multiplication(){
int a=80;
int b=40;
int c=a*b;
System.out.println("The result of Multiplication is:-"c);
public void division(){
int a=80;
int b=40;
int c=a/b;
System.out.println("The result of Division is:-"c);
//Anaother class C that use B's method
class C{
public static void main(String[]args){
//what is the differnce
//I have a doubt why we use this line
A a=new B();
a.add();
B b=new B();
b.add();
I have a doubt,In class C I am accessing the B's add()through 2 referance variables one is class type and another is interface type.ok
My doubt is what's the differance?
which is adviceable to use?
if Interface reference is advisable,weather it will allocate memory at runtime or compile time?
a class variable will allocate memory at runtime or compile time?
thanks
Biswo
Edited by: Biswo on Dec 3, 2008 8:29 AM

Biswo wrote:
My doubt is what's the differance?
which is adviceable to use?They're equivalent from a performance standpoint so it boils down to whether you want the reference variable to be of type A or B, which is a design consideration.
In both cases the B object is allocated at runtime and the add method is bound at runtime.
The Java language is very efficiently implemented so you don't have to worry about things like this. Concentrate on proper design instead.

How to run applet after open an IE vit in labview?

Dear all,
In my application, I open IE using labview vit to run an html page which contains an applet.
But the problem is at my computer at home, when I run the JVM automatically shows up and run the applet, but at the office, this JVM does not show up show it can not run (although if I open it using standalone IE, it runs fine)
I did check for the IE settings, windows Xp (sp2), JVM 1.5, and others but still not solved.
Is there anything to do with labview to make sure that the JVM run the applet?
Thanks.

Thanks,
I did as you advise, but still not work.
For a more clear explaination:
I attach 4 files (in zip file called esco.vip, pls change back to .zip and open it): one is labview file to open the IE, one is the html file, the other is the .class file of java applet, the last one is the source code of this java applet (for you to recompile and check the safety in case you doubt my .class file about security). Pls put all of them in the same folder
So, if your computer has the JVM, you open the html file using an IE, you will be able to see scroll text runing.
if you open the labview vi, key in the file name, and run it, my home computer can see, but my office computers is not allowed to see (it will appear the grey line). I'm not sure you computer will experience the same (hope you do )
So my question is: how to make it running in labview?
I had check the setting and configuration, they are quite similar:
-win XP, SP2
-IE 6
Attachments:
esco.zip ‏70 KB

Create URL to specific Business Object for a CRM using Portal integration

Hello CRM Community,
we're using the CRM Portal integration. To update our business users with tasks we use the standard functionality to send Alerts using the function module SALRT_CREATE_API. It allows to specify a URL that is added to the E-Mail created in the alert using the Table parameter IT_ACTIVITIES. This URL should be filled with a direct link to the business object that must be changed. For the stand-alone CRM there is the static Method CREATE_URL of the class CL_CRM_WEB_UTILITY to build such an URL. But I was not able to find a similar class/method/function module when the CRM is used integrated in the portal. Has anyone a simmilar requirement and was able to solve it?
Best regards
Gregor

Hell0
Gregor Wolf
Yes i have also same doubt regarding class this integration , Please share this stuff with me !! Nice Question !!
Thanks & regards
Asish

Reading a text file into a StringBuffer?

Hey all,
I've taken a year of Java programming class so far, but I doubt my class is ever going to get in to things like this. I've been trying to develop a program that reads a small text file into a StringBuffer for manipulation and use in the program. I've been looking around the web, but thus far all I've seen are things like FileInputStream, in the java.io.* package; nothing about StringBuffers.
And I'm pretty sure it's kind of hard, too. If someone could give me a simple(?) explanation, or a link to a tutorial that shows you this or something, it would be much appreciated.
Also, is it possible to pull an integer out of a string? I was just wondering this, I don't think you can cast a string to an int or anything. Ha ha.
~Darkslime, Java student

Hey all,
I've taken a year of Java programming class so far,
but I doubt my class is ever going to get in to
things like this. I've been trying to develop a
program that reads a small text file into a
StringBuffer for manipulation and use in the program.
I've been looking around the web, but thus far all
I've seen are things like FileInputStream, in the
java.io.* package; nothing about StringBuffers.
And I'm pretty sure it's kind of hard, too. If
someone could give me a simple(?) explanation, or a
link to a tutorial that shows you this or something,
it would be much appreciated.
Also, is it possible to pull an integer out of a
string? I was just wondering this, I don't think you
can cast a string to an int or anything. Ha ha.
~Darkslime, Java student
try {
        BufferedReader in = new BufferedReader(new FileReader("infilename"));
        String str;
        while ((str = in.readLine()) != null) {
            process(str);
        in.close();
    } catch (IOException e) {
    }

Bouncing Apache for OAF deployment

Hi,
We are facing issue in reflection of .class file changes after Apche port bounce for OAF custom development on R12.
We deploy our BC4J and Controller codes (.xml and .class) to $JAVA_TOP and Import the page xml to MDS. After this we request the DBA to bounce the apache server with clear cache option. After the bounce the page changes are getting reflected, but BC4J changes are not.
In the mean time when DBA recompiles entire jsp files manually using “ojspCompile.pl” the changes are getting reflected. This manual compilation takes about 30 mins which is not desired.
I am not clear why its happening, as we never deploy any JSPs, so how JSP compilation is refreshing the changes? Logically the Apche bounce shall reflect the change.
Please suggest!
Thanks:
Shrawan

Shrawan,
If you have bounced the server and compiled all the java files on the server, there is no reason that your BC4j changes in BC4J compoenent files are not gettng reflected.(If u still are in doubt of class files on server not being the latest delete the class files and then compile java files.)
Have u put debug messages and chacked the log to see the flow?Moreoever, as far i know R12 has OC4J server and not Apache.
Y ur dba is compililng jsp files? oa framework pages don't include jsp files, unless otherwise u have used specially.
--Mukul

Aborting an JAVA method Call

Hi
please clarify my doubt.
public class P1
public static void main(String args[])
     P2 obj = new P2();
     obj.doSomething(input);
     System.out.println("continue");
class P2
public void doSomething(input)
     //validate
     //update
     //write to disk
In the above program, the doSomething method should take less than 1 sec.
if it takes more i need to abort the call and
continue printing the SOP. I mean it should return to main program. but the updation
and writing to disk should take place. how can i do that? can i do that or not?
thanks in advance

In the above program, the doSomething method should take less than 1 sec.
if it takes more i need to abort the call and continue printing the SOP. Have a thread which calls the SOP every second whether the write completes in time or not.
I mean it should return to main program. but the updation and writing to disk should take place. If you abort the operation it will not still happen correctly. In fact you could corrupt the file. Stopping the thread prematurely can result in a memory leak. How important is to you that you abort after 1 sec.

Accessing protected members

Hi,
Can one of you please clarify the following doubt.
CLASS A
package com;
public class A {
     protected String name = "JAVA";
     protected void m1(){
          System.out.println("m1");
CLASS B
package com.abc;
import com.A;
public class B extends A {
     public static void main( String [] args ) {
          B b = new B();
          b.mt();
     public void mt() {
          System.out.println("name --> " + name);
          m1();
CLASS C
package com.abc.xyz;
import com.abc.B;
public class C extends B {
     public static void main( String [] args ) {
          C c = new C();
          c.mttt();
     public void mttt() {
          System.out.println("name --> " + name);
          m1();
====================================
Now in one of the books I read that a protected member of parent class (say A) is accesible thru inheritance in a subclass in different package (say B). Perfect!
But also says that another class (say C) inheriting the above subclass either in a the same or different package cannot access the protected members of the parent class (A).
Surprisingly above code compiles and runs perfectly on my machine. Checked the JDK version and is 1.3 but the books is for 1.4
Can some one please clarify which is correct.
Thanks in Advance.

I was expecting a compilation error (in class C as it cannot access the protected members of class A) according to the book I read. But I observed that it is compiling and running perfectly.
Following the code again for clarity:
CLASS A
package com;
public class A {
     protected String name = "JAVA";
     protected void m1(){
          System.out.println("m1");
CLASS B
package com.abc;
import com.A;
public class B extends A {
     public static void main( String [] args ) {
          B b = new B();
          b.mt();
     public void mt() {
          System.out.println("name --> " + name);
          m1();
CLASS C
package com.abc.xyz;
import com.abc.B;
public class C extends B {
     public static void main( String [] args ) {
          C c = new C();
          c.mttt();
     public void mttt() {
          System.out.println("name --> " + name);
          m1();
}Message was edited by:
talk2key

Doubt in inner classes

public class Outer
           public static void main(String argv[])
                     Outer o=new Outer(); //1
                     Inner i =o.new Inner(); //2
                     //Inner i =new Inner(); //3
     i.showName();
         public      class Inner{
                void showName()
        System.out.println("hi");
      }//End of Inner class
}I have few doubt regrd the above program..
1)when i create an inner class instance as in line 3,..Iam having an err like
non-static variable this cannot be referenced from a static context.. Bcas Inner is a non static member of class Outer it cant be referred without an instance of Outer as in line 2.. But my doubt is why it doesnt give such error (of static context issue) in the case of line 1...its a silly dbt but iam confused ...
2..Can we refer the inner class without outer class like in line 2., I have used
Inner without Outer ..is this ok... or shuld we use as
Outer.Inner i =o.new Inner(); //2
3)In the above line We r associating the instance of inner class with the instance of outer class and the type of inner class with the type of outer class (Outer.Inner )..wht does this mean..
can anyone pls help me understand this..
thnx.
mysha..

public class Outer
public static void main(String argv[])
Outer o=new Outer(); //1
er o=new Outer(); //1
Inner i =o.new Inner(); //2
//Inner i =new Inner(); //3
     i.showName();
public      class Inner{
void showName()
        System.out.println("hi");
}//End of Inner class
}I have few doubt regrd the above program..
1)when i create an inner class instance as in line
3,..Iam having an err like
non-static variable this cannot be referenced from a
static context.. Bcas Inner is a non static member of
class Outer it cant be referred without an instance
of Outer as in line 2.. But my doubt is why it doesnt
give such error (of static context issue) in the case
of line 1...its a silly dbt but iam confused ...
Static methods of a class exist as soon as Java loads the class. Regular, or non-static, methods of a class belong to an object and only come into existence after you create an object of the class. Regular methods are called by an object. Static members are called using the class name.
Now, examine this simple program:
class Apple
     private String color;
     public Apple(String color)
          this.color = color;
     public void show()
          System.out.println("apple color: " + color);
     public static void greeting()
          System.out.println("Hello from the Apple class.");
public class Demo
     public static void main(String[] args)
          Apple.greeting(); //1
          Apple a = new Apple("red"); //2
}After the Apple class loads, any static methods in the class exist. Since greeting() is a static method of the Apple class, it can be called in line 1 before any Apple objects exist. But, what about line 2? How can the Apple constructor with the String parameter, which is a method in the Apple class, be called? The constructor isn't declared as a static, so it shouldn't exist in that regard, and no objects of the class exist. So, when and how did the constructor come into existence. That seems to be the question you're struggling with. I think the answer is: a constructor sort of acts like a static method. In order to be able to call a constructor, the constructor must exist as soon as the class loads and before any objects exist. The result is, you can call a constructor at any time.
I think your example is similar to my example, but you only have one class:
public class Outer
public static void main(String argv[])
Outer o=new Outer(); //1
}After Java loads Outer, any static methods in Outer exist. Since main() is a static method, it exists. Subsequently, java calls the static main() method to begin execution of your program. In line 1, you call the default constructor for Outer. The default constructor isn't static, so it shouldn't exist, but just like the constructor in my example above, the default constructor acts like a static method, and therefore you can call it without getting an error.
Inner i =o.new Inner(); //2
2..Can we refer the inner class without outer class
like in line 2., I have used
Inner without Outer ..is this ok... or shuld we use
as
Outer.Inner i =o.new Inner(); //2
I'm not sure what the difference is. In both cases you end up with an object that was created with the expression:
o.new Inner()
you just have a different type for your object, i.e. Outer.Inner versus Inner.
3)In the above line We r associating the instance of
inner class with the instance of outer class and the
type of inner class with the type of outer class
(Outer.Inner )..wht does this mean..
can anyone pls help me understand this..
I think you said it: it means you have an Inner object that is "associated" with an Outer object. Like any other regular member in the Outer class, Inner can refer to any members of Outer. (A static member of Outer can't refer to regular members of Outer because static members exist before any objects exist, and when no objects exist, the regular members don't exist.) That means an Outer object must exist before you can create an Inner object.

Few basic doubts about accessing AM from backing bean class

Hi ADF experts,
I have just started working in ADF Faces.I made a sample search page.My page is attached to a managed backing bean. I have attached command button on my page to a custom method in backing bean class.
So on, click of button this method is called in backing bean.Now, i have few doubts:
1)How to get values of various UI beans in this event code?
2)I am accesing AM , in my method with this code:
FacesContext facesContext = FacesContext.getCurrentInstance();
ExternalContext extContext = facesContext.getExternalContext();
Application app = facesContext.getApplication();
DCBindingContainer binding = (DCBindingContainer)app.getVariableResolver().resolveVariable(facesContext, "bindings");
//Accessing AM
ApplicationModule am = binding.getDataControl().getApplicationModule();
iS this correct ?
3) After getting handle of am how to call my custom method in AM Class?there was "invokeMethod" API in application module class in OAF, is there any such method here?
Please help me.
--ADF learner.

Thanks for ur response Frank, actually I am from OA Framework back ground.It would be great if help us a little with ur valuble thoughts.
OA Framework also uses bc4j in model layer of framework. We have a requirement where our existing developers from OA Framework have to move to ADF to make a new application where time lines are quite strict.If this would not be possible we will switch to plain jsp and jdbc,but our tech experts say ADF Faces is the best tech.
In OA Framework, Application Module is key class for all busiess logic and Controller is used for page navigation. So, I m just trying to find the same similarity , where we write we add all event codes in custom action methods in the backing bean class of page, which we consider equivalent to process form request method in Controller class of OAF.
But there are two things, I still want to know:
1)While page render, how to call specific AM methods(like setting where clause of certain VOs)
2)In action methods, the way i described(I found that in one thread only)to access AM, what is wrong in that?Also, I went through
http://radio.weblogs.com/0118231/stories/2004/09/23/notYetDocumentedAdfSampleApplications.html
where coule of examples use similar approach to access AM from backing bean class and call custom methods of AM(Doing various, deletes etc from VOs).
3)In these methods can we set any property of beans on the page, I am asking because in OAF, generally we use PPR for js alternatives.But all properties of beans cannot be set in post event.
Thanks and Regards
--ADF Learner

Doubt in classes

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