Problems using a static class extending JSPDynPage

When I use the pdk with netweaver for creating a new portal object and I want to create a new PortalComponent (JSPDynpage) the pdk generates me the next code:
public class TestJspDynPage extends PageProcessorComponent {
public DynPage getPage(){
      return new TestJspDynPageDynPage(); }
public <b>static</b> class TestJspDynPageDynPage extends JSPDynPage{
    public void doInitialization(){ }
    public void doProcessAfterInput() throws PageException {}
    public void doProcessBeforeOutput() throws PageException {}
Is there any reason for creating the new class that extends JSPDynPage static ?
Regards.

Hi,
That is a common problem, all variables in your JSPDynPage, should be saved in IPortalComponentSession/HttpSession instead of having instance/class variables.
http://help.sap.com/saphelp_nw70/helpdata/en/fc/f28f414141a709e10000000a155106/frameset.htm
http://help.sap.com/saphelp_nw70/helpdata/en/a0/3b7f41009d020de10000000a1550b0/frameset.htm
Greetings,
Praveen Gudapati

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Message was edited by: steff yan

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Hi Joost,
This all seems to be pretty complicated. Not to mention that you can not
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Why don't you want using the database?
"Joost Ouwerkerk" <[email protected]> wrote in message
news:[email protected]..
I am designing an EJB component (MessageDrivenBean) that requires
dynamic ("hot") configuration changes. As such, the bean must be
notified somehow of configuration changes in the DB (rather than have
to poll the DB for changes at every method call).
I'm thinking of implementing this functionality using a static class
instance (singleton) that is shared between the multiple instances of
the bean. This static instance would listen on a JMS topic for
configuration change events and update its internal cache accordingly
(by getting the configuration information from the DB). The beans
would then access this in-memory static instance everytime they need
configuration info instead of polling the database. By using the JMS
topic, I guarantee that clustered instances of Weblogic will all be
notified of the database changes (each instance would have its own
"cache" singleton).
I'm pretty sure all of this will work, but I'm equally sure that I'm
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Any ideas why this would generate an internal error - referring to a static class function in that class constructor's parameter signature?
Test case (on 11.2.0.2) as follows:
SQL> create or replace type TMyObject is object(
2          id      integer,
3          name    varchar2(30),
4
5          static function DefaultID return integer,
6          static function DefaultName return varchar2,
7
8          constructor function TMyObject(
9                  objID integer default TMyObject.DefaultID(), objName varchar2 default TMyObject.DefaultName()
10          )return self as result
11 );
12 /
Type created.
SQL>
SQL> create or replace type body TMyObject is
2
3          static function DefaultID return integer is
4          begin
5                  return( 0 );
6          end;
7
8          static function DefaultName return varchar2 is
9          begin
10                  return( 'foo' );
11          end;
12
13          constructor function TMyObject(
14                  objID integer default TMyObject.DefaultID(), objName varchar2 default TMyObject.DefaultName()
15          )return self as result is
16          begin
17                  self.id := objId;
18                  self.name := objName;
19                  return;
20          end;
21
22 end;
23 /
Type body created.
SQL>
SQL> declare
2          obj     TMyObject;
3 begin
4          obj := new TMyObject();
5 end;
6 /
declare
ERROR at line 1:
ORA-06550: line 0, column 0:
PLS-00801: internal error [phd_get_defn:D_S_ED:LHS]If the static class functions are removed from the constructor and applied instead inside the constructor body, it works without error. Likewise you can call the constructor with the static class functions as parameters, without an internal error resulting.
SQL> create or replace type TMyObject is object(
2          id      integer,
3          name    varchar2(30),
4
5          static function DefaultID return integer,
6          static function DefaultName return varchar2,
7
8          constructor function TMyObject(
9                  objID integer default null, objName varchar2 default null
10          )return self as result
11 );
12 /
Type created.
SQL>
SQL> create or replace type body TMyObject is
2
3          static function DefaultID return integer is
4          begin
5                  return( 0 );
6          end;
7
8          static function DefaultName return varchar2 is
9          begin
10                  return( 'foo' );
11          end;
12
13          constructor function TMyObject(
14                  objID integer default null, objName varchar2 default null
15          )return self as result is
16          begin
17                  self.id := nvl( objId, TMyObject.DefaultID() );
18                  self.name := nvl( objName, TMyObject.DefaultName() );
19                  return;
20          end;
21
22 end;
23 /
Type body created.
SQL>
SQL> declare
2          obj     TMyObject;
3 begin
4          obj := new TMyObject();
5 end;
6 /
PL/SQL procedure successfully completed.
SQL>
SQL> declare
2          obj     TMyObject;
3 begin
4          obj := new TMyObject(
5                          objID => TMyObject.DefaultID(),
6                          objName => TMyObject.DefaultName()
7                  );
8 end;
9 /
PL/SQL procedure successfully completed.
SQL> Had a quick look on support.oracle.com and did not turn up any specific notes dealing with the use of static class functions in the parameter signature of the constructor. Known issue? Any other workaround besides the one above?

Hi,
there is a bug: "Bug 8470406: OBJECT INSTANCE CREATION FAILS WITH ERROR PLS-00801 IN 11GR1", it shows the behaviour in 11g but not in 10.2. It gives exactly the symptoms you also see, move it to the body and it works. But there is no solution/patch given.
Herald ten Dam
http://htendam.wordpress.com

Static Classes/Methods vs Objects/Instance Classes/Methods?

Hi,
I am reading "Official ABAP Programming Guidelines" book. And I saw the rule:
Rule 5.3: Do Not Use Static Classes
Preferably use objects instead of static classes. If you don't want to have a multiple instantiation, you can use singletons.
I needed to create a global class and some methods under that. And there is no any object-oriented design idea exists. Instead of creating a function group/modules, I have decided to create a global class (even is a abstract class) and some static methods.So I directly use these static methods by using zcl_class=>method().
But the rule above says "Don't use static classes/methods, always use instance methods if even there is no object-oriented design".
The book listed several reasons, one for example
1-) Static classes are implicitly loaded first time they are used, and the corresponding static constructor -of available- is executed. They remain in the memory as long as the current internal session exists. Therefore, if you use static classes, you cannot actually control the time of initialization and have no option to release the memory.
So if I use a static class/method in a subroutine, it will be loaded into memory and it will stay in the memory till I close the program.
But if I use instance class/method, I can CREATE OBJECT lo_object TYPE REF TO zcl_class then use method lo_object->method(), then I can FREE lo_object to delete from the memory. Is my understanding correct?
Any idea? What do you prefer Static Class OR Object/Instance Class?
Thanks in advance.
Tuncay

@Naimesh Patel
So you recommend to use instance class/methods even though method logic is just self-executable. Right?
<h3>Example:</h3>
<h4>Instance option</h4>
CLASS zcl_class DEFINITION.
METHODS add_1 IMPORTING i_input type i EXPORTING e_output type i.
METHODS subtract_1 IMPORTING i_input type i EXPORTING e_output type i.
ENDCLASS
CLASS zcl_class IMPLEMENTATION.
METHOD add_1.
    e_output = i_input + 1.
ENDMETHOD.
METHOD subtract_1.
    e_output = i_input - 1.
ENDMETHOD.
ENDCLASS
CREATE OBJECT lo_object.
lo_object->add_1(
exporting i_input = 1
importing e_output = lv_output ).
lo_object->subtract_1(
exporting i_input = 2
importing e_output = lv_output2 ).
<h4>Static option</h4>
CLASS zcl_class DEFINITION.
CLASS-METHODS add_1 IMPORTING i_input type i EXPORTING e_output type i.
CLASS-METHODS subtract_1 IMPORTING i_input type i EXPORTING e_output type i.
ENDCLASS
CLASS zcl_class IMPLEMENTATION.
METHOD add_1.
    e_output = i_input + 1.
ENDMETHOD.
METHOD subtract_1.
    e_output = i_input - 1.
ENDMETHOD.
ENDCLASS
CREATE OBJECT lo_object.
lo_object->add_1(
zcl_class=>add_1(
exporting i_input = 1
importing e_output = lv_output ).
lo_object->subtract_1(
zcl_class=>subtract_1(
exporting i_input = 2
importing e_output = lv_output2 ).
So which option is best? Pros and Cons?

Singleton instance vs static class

Hi,
I often got confused to identify when is better to use a singleton instance and when is better use a static class insted.
Could someone please advise what criteria should be observed to decide which way is better?
Thanks in advance,

A class with all static methods generally connotes a helper class that supplies behavior or enforces business rules of other objects. A class with only state and no behavior is typically encountered in distributed systems, also known as a transfer object. Most true objects have both state and behavior. A singleton is simply a normal object that ensures only a single instance of itself will ever be created and returned for use to a caller.
- Saish

What is static class ?

I know about static function.
What is static class?
What is the use of static class?
how can i use static class.?
Give me a static class example?

Static class and singleton are similar but they are not the same. A singleton is instantiated, and you have a reference to it - just one single reference no matter how many times you instantiate it. Singletons are good for data storage, config settings, loggers things that you may need all around your application, but you always want the same one.
A static class is not instantiated - an example of this is Flash's Math class. You can just do Math.sin() and get a result, you don't instantiate it in order to use it. Static classes are good for utility classes... essentially they are simply a namespace for a group of methods.
Oh, and you said you know about static function - what is static class - a static class then is just one that contains only static functions/methods.

Problems using a static class extending JSPDynPage

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