Using SequenceFactory getNext in persistent object constructor

Hi,
Rightly or wrongly (maybe wrongly cos I am getting problems...)
In my persistent object constructors, I am initialising the objects id
field using the sequence factory getNext() method.
If I run the schematool on a blank DB with no tables then it works fine -
classes are enhanced, tables created.
But if I run it again on the same db, it fails on the first persistent
object, with this stack trace:
[java] java.lang.ExceptionInInitializerError:
javax.jdo.JDOFatalUserException: The system could not initialize; the
following registered persistent types are missing metadata or have not
been enhanced: [class com.rabobank.reef.tradeadapters.dto.ReefSystem].
[java] at
com.solarmetric.kodo.impl.jdbc.JDBCPersistenceManagerFactory.loadPersistentTypes(JDBCPersistenceManagerFactory.java:293)
[java] at
com.solarmetric.kodo.impl.jdbc.JDBCPersistenceManagerFactory.setup(JDBCPersistenceManagerFactory.java:256)
[java] at
com.solarmetric.kodo.runtime.PersistenceManagerFactoryImpl.privateSetup(PersistenceManagerFactoryImpl.java:872)
[java] at
com.solarmetric.kodo.runtime.PersistenceManagerFactoryImpl.getConnectionFactory(PersistenceManagerFactoryImpl.java:223)
[java] at
com.solarmetric.kodo.impl.jdbc.JDBCPersistenceManagerFactory.setLogWriter(JDBCPersistenceManagerFactory.java:175)
[java] at com.rabobank.util.kodo.JDOFactory.<init>(Unknown Source)
[java] at com.rabobank.util.kodo.JDOFactory.getInstance(Unknown
Source)
[java] at
com.rabobank.util.kodo.JDOFactory.getNextPrimaryKey(Unknown Source)
[java] at
com.rabobank.reef.tradeadapters.dto.GenericObject.<init>(Unknown Source)
[java] at
com.rabobank.reef.tradeadapters.dto.ReefSystem.<init>(Unknown Source)
[java] at
com.rabobank.reef.tradeadapters.dto.ReefSystem.<clinit>(Unknown Source)
[java] at java.lang.Class.forName0(Native Method)
[java] at java.lang.Class.forName(Class.java:115)
[java] at
com.solarmetric.kodo.impl.jdbc.schema.SchemaTool.main(SchemaTool.java:1115)
[java] Exception in thread "main"
Which looks like the sequence factory requires an initialised system to be
accessed, but it is trying to init the system when it is called?
But it works on a clean db...
I am just going about this the wrong way or is it a simple bug in my
procedure?
Thanks,
Chris

heres the exact error message im getting
Exception in thread "main" java.lang.NullPointerException
at instrument.<init>(instrument.java:15)
at iContainer.populate(iContainer.java:34)
at main.main(main.java:7)
the bolded line is the erroneous one
public instrument(int newID, String newType, String newRenters [], int newPrice, String newKey, boolean newNeedsRepairs)
          super(newID);
          type = newType;
          for ( int x = 0; x < newRenters.length; x++)
               *renters[x] = newRenters[x];*
          price = newPrice;
          key = newKey;
          needsRepairs = newNeedsRepairs;
     }

Similar Messages

Use of Ref and Persistent Objects

Hi,
I am using OTT and I have created a sub class for the OTT generated class
i.e.,
class A:public PObject//OTT generated
class B:public A//created by me
for Class B I need to write a static function queryKey() which will return a pointer to persistent object of class B,
i.e.,
B* B::queryKey(Number c,Number d);
I have implemented it something like this...
B* B::queryKey(      OCCI_STD_NAMESPACE::string c,
                    oracle::occi::Number d,
                    oracle::occi::Number e)
     Statement *stmt=NULL;
     ResultSet *rset=NULL;
     CCPDKey *handle=0;
     try
          string query="SELECT REF(a) FROM ";
          query=query+tableName+ (" a WHERE C=:1 AND D=:2 AND E=:3 ");
          stmt=conn->createStatement(query);
          stmt->setString(1,c);
          stmt->setNumber(2,d);
          stmt->setNumber(3,e);
          rset=stmt->executeQuery();
          if(rset->next())
               Ref < B > r1(rset->getRef(1));
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          stmt->closeResultSet (rset);
     conn->terminateStatement (stmt);
          throw;
     stmt->closeResultSet (rset);
conn->terminateStatement (stmt);
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Is this the correct way of doing it,
Will the persistent object pointed by handle get destroyed as the scope of Ref i.e.,r1 ends..?
If so, what is the correct way of doing it..?
I need this method to return a B*.
If the way I have used is correct,Do I need to delete the variable handle once I am done using it..?I saw in "Using OCCI: Best Practices" that the persistent object should not be deleted unless you are doing rollback.
I am new to OCCI and i am confused
Please help
Ajey

In the function B::queryKey(), the Ref<B> variable will go out of scope at the end of the if {} statement and the Ref will be unpinned. So, the "handle" object pointer variable will be pointing to an object that could be freed anytime by the garbage collector.
Can you change your design to return a Ref<B> from B::queryKey()? If you want to return the object pointer directly then you will have to manage pining/unpining of the object. With Refs, the pining/unpining is transparently managed by OCCI and with the "->" operator you can write code which is the same as with the object pointer.
Thanks,
Shankar

Using null for parameterized "newInstance(Object [])" method in Object[].

I have a really serious problem. I am creating instances of specific classes by using reflection techniques. I am reading a flat file, finding class from its name and creating it by using its parameterized constructor. Example:
line 1: Dummy("A",Dummy2("B"),12,,"C");
I create an instance of Dummy with parameters "A", an instance of Dummy2 object with value "B", 12 (I use here Integer as wrapper), null (There is no wrapper for null :( ) and "C".
I find constructor by using findConstructors() and looking their parameter counts, creating an object array with given values and calling:
constructorIFoundBefore.newInstance(objectArrayIPrepared);
But!!!
Because I use null directly, I got this message:
java.lang.IllegalArgumentException: argument type mismatch
     at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
     at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
     at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
     at java.lang.reflect.Constructor.newInstance(Constructor.java:274)
     at reader.parser.ObjectCreator.createObjectFromObjectItem(ObjectCreator.java:192)
     at reader.parser.ObjectCreator.createObjectFromParseItem(ObjectCreator.java:112)
     at reader.parser.ObjectCreator.createObject(ObjectCreator.java:78)
     at reader.analyzer.FileAnalyzer.analyzeAndCreateObjects(FileAnalyzer.java:95)
     at reader.ReverseReader.main(ReverseReader.java:43)
I will be very glad if you help me.
Thanks a lot!
Gokcer

I said something wrong. Sorry. While invoking a method (or a constructor) we need an object array which are equivalent to parameters. For example to call a method or constructor for class A;
class A {
int age;
String name;
public A(int age, String name){
this.age = age;
this.name = name;
public set(int age, String name){
this.age = age;
this.name = name;
we use in any place
A a1 = new A(12,"Gokcer");
A a2 = new A(15,null);
To achieve this by using reflection techniques, we must find constructor with two parameters of class A. At this point "BetterMethodFinder" will give great help.
After finding right constructor, we must create an object array to tell the constructor parameters (age and name). At this point we need an object array which stores our parameters. Code must be like this.
Object []params = new Object[2]; // we have two parameters.
params[0] = new Integer(12); // we can't use params[0]=12
// because 12 is not an object. (It is a
// primitive type)
params[1] = "Gokcer";
Now create the new object.
A a1;
a1 = constructorWeFound.newInstance(params);
While creating param[], we could also use:
Object []params = new Object[2] {new Integer(12),"Gokcer"};
While creating a2, we can use "null" directly for second parameter.
params = new Object[2] = {new Integer(15), null};
or
Object []params = new Object[2];
params[0] = new Integer(15);params[1] = null;
Thanks again everyone who replied me.
My sincerely...

How can i get the unitOfWork or the persisting object in to my listener???.

hi,
i have a listener class which extends SessionEventAdapter ....as shown below
public class MyLister extends SessionEventAdapter{
public void postCommitUnitOfWork(SessionEvent event) {
System.out.println("POST COMMIT OF WORK");
// How can i get the unitOfWork or the persisting object in to my listener???
Another class makes use of this listener by adding the listener into a getEventManager() of a session ....
public final class AetbProcessStatusClient {
public static final void main(String[] args)
{ Project project =
XMLProjectReader.read("META- INF/AetbProcessStatus.xml",
Thread.currentThread().getContextClassLoader());
DatabaseSession session = project.createDatabaseSession();
MyLister myListener = new MyLister();
session.getEventManager().addListener(myListener);
session.login();
UnitOfWork uow = session.acquireUnitOfWork();
uow = session.acquireUnitOfWork();
Vector vec =
(Vector)uow.executeQuery("SQFunctionIdProcessStatus", AetbProcessStatus.class);
AetbProcessStatus processStatus = new AetbProcessStatus();
processStatus = (AetbProcessStatus)vec.get(0);
processStatus.setRunStat('E');
processStatus.setProgramSeqNo(10);
uow.commit();
now my question --> How can i get the unitOfWork or the persisting object in to my listener???....
ie the object "processStatus" into my listener

The SessionEvent's session (getSession()), should be the UnitOfWork. You can access the UnitOfWork or UnitOfWorkImpl methods to access the objects in the unit of work. getUnitOfWorkChangeSet() will return the changes made in the UnitOfWork.
-- James : http://www.eclipselink.org

Switch between transient and persistent objects?

Hi Folks,
I'm Re: transient object to persistent to ask this type of question, but couldn't find an answer.
Using persistent classes, does anyone know an elegant way to convert a transient object to a persistent one and vice versa? There is no standard functionality provided that I can see, and cloning the object results in clashing keys.
What am I trying to accomplish?
I need an object instance which <i>may</i> exist in the DB and if not, it <i>may</i> need to be saved for future use. I'm using a table with key fields K1 and K2 and the app will ask for an object instance using the full key K1+K2.
If the object doesn't find a DB record for K1K2 then it should instantiate itself with values for K1blank. Here is where I'm considering transient in order to provide the app with default functionality defined in record K1+blank.
If a write access occurs to a transient object then is should become persistent and the K1+K2 record be created.
Any ideas appreciated.
Cheers,
Mike

Hi Mike,
I written something similar working on Persistent Objects.
The only point of attention is that you cannot create a new persistent while a transient is resident in memory.
This is checked by the OS system during the creation of a new persistent:
in method CREATE_PERSISTENT of Basis Class, there is a check on the existing object:
* Precondition   : No object exists with the given business key, neither
*                  in memory nor on database.
So, you can create a new transient, fill it with the values you need and then pass this values to the agent to create a new persistent, but only after releasing the existing transient (because they will have the same key).
I've solved the problem like this:
METHOD flush.
"IMPORTING value(im_transient) TYPE REF TO zcl_liquidate_daily_bo
"IMPORTING value(im_commit) TYPE xfeld
"IMPORTING value(im_agent) TYPE REF TO zca_liquidate_daily_bo
"RETURNING value(re_persistent) TYPE REF TO zcl_liquidate_daily_bo
"--> raised by event PERNR_PROCESSED
DATA: s_dip_liq TYPE zhr_tm_dip_liq.
s_dip_liq-zpernr    = im_transient->get_employee_no( ).
s_dip_liq-zsocmat   = im_transient->get_matricola_legale( ).
s_dip_liq-zdataev   = im_transient->get_event_date( ).
s_dip_liq-zcodev    = im_transient->get_event_type( ).
s_dip_liq-zdescev   = im_transient->get_event_descr( ).
s_dip_liq-zmotev    = im_transient->get_event_reasn( ).
s_dip_liq-zmeseall = im_transient->get_mese_allineamento( ).
s_dip_liq-zannoall = im_transient->get_anno_allineamento( ).
* // Invalidate the transient before create the persistent!
im_agent->if_os_factory~release( im_transient ).
CLEAR im_transient.
IF im_commit EQ abap_true.
    TRY.
re_persistent =
im_agent->create_persistent( EXPORTING i_anno_allineamento = s_dip_liq-zannoall
                                               i_mese_allineamento = s_dip_liq-zmeseall
                                               i_employee_no       = s_dip_liq-zpernr
                                               i_event_date        = s_dip_liq-zdataev
                                               i_event_type        = s_dip_liq-zcodev
                                               i_event_descr       = s_dip_liq-zdescev
                                               i_event_reasn       = s_dip_liq-zmotev
                                               i_matricola_legale = s_dip_liq-zsocmat ).
      CATCH cx_os_object_existing.
    ENDTRY.
    COMMIT WORK AND WAIT.
ENDIF.
ENDMETHOD.
This method is called inside a loop on a table that containes references to transient objects.
For each object I perform some tasks, and if all it's ok I raise the event PERNR_PROCESSED, which automatically calls this method FLUSH, transferring the transient to the persistent.
Return Object is the new persistent, which will be passed back to the internal table, changing the content from the transient to the new persistent.
Hope this helps,
Roby.

Problem with Persistent Object as Reference Attribute of Persistent Object

Hello All,
I have a problem with a persistent class that contains a reference attribute to another persistent class. I can write the reference object attribute to the DB but when I read the reference attribute back from the DB the object is null. Allow me to explain...
I have two tables; one is a data table with one key field of type OS_GUID, the second is a mapping table with several business key fields and two further fields; an instance GUID and a class identifier GUID. The data table is used to contain all the data for an object. The mapping table is used to hold a relationship between the GUID assigned in the data table and the business key. The mapping table has been structured in this way by following the help here:
http://help.sap.com/saphelp_erp2005vp/helpdata/en/df/e785a9e87111d4b2eb0050dadfb92b/frameset.htm
and the field mapping in persistent class for the mapping table has been mapped following the help here:
http://help.sap.com/saphelp_erp2005vp/helpdata/en/06/f23c33638d11d4966d00a0c94260a5/frameset.htm
The code I use to create entries in the data and mapping table is:
<-snip->
DATA:
    gv_blank_data_guid TYPE REF TO zcl_ps_data,
    gv_data_guid       TYPE        os_guid,
    go_data_ps         TYPE REF TO zcl_ps_data,
    go_data_agent      TYPE REF TO zca_ps_data,
    go_data_map_ps     TYPE REF TO zcl_ps_data_map,
    go_data_map_agent TYPE REF TO zca_ps_data_map,
    go_exc             TYPE REF TO cx_root.
go_data_agent = zca_ps_data=>agent.
go_data_map_agent = zca_ps_data_map=>agent.
TRY.
Check if there's already data with the business key on the DB
      go_data_map_ps = go_data_map_agent->get_persistent(
                         i_data_ref     = iv_data_ref
                         i_action       = iv_action ).
... if there is then exit.
      EXIT.
    CATCH cx_root INTO go_exc.
ENDTRY.
TRY.
Create the data...
      go_data_ps = go_data_agent->create_persistent(
                       i_root_guid = gv_blank_data_guid
                       i_req_date = iv_req_date ).
      TRY.
... finally, write the new data to the data business key map table
          go_data_map_ps = go_data_map_agent->create_persistent(
                             i_data_ref     = iv_data_ref
                             i_action       = iv_action
                             i_data_guid    = go_data_ps ).    "note1
        CATCH cx_root INTO go_exc.
      ENDTRY.
    CATCH cx_os_object_not_found.
ENDTRY.
COMMIT WORK.
<-snip->
The fact that it is possible to pass the object GO_DATA_PS in the call to GO_DATA_MAP_AGENT (the line that I've put the comment "note1" on) indicates to me that the reference to the data persistent object can be written to the DB by the mapping persistent object. After executing the above code the mapping table object and class identifier fields are populated. Also, if multiple entries are written to the tables then the class identifier field in the mapping table is always the same and the object ID is different as expected.
However, the problem I have is if I read an object from the DB using the business key with the following code:
<-snip->
DATA:
    gv_req_date        type        datum,
    gv_data_guid       TYPE        os_guid,
    go_data_ps         TYPE REF TO zcl_ps_data,
    go_data_agent      TYPE REF TO zca_ps_data,
    go_data_map_ps     TYPE REF TO zcl_ps_data_map,
    go_data_map_agent TYPE REF TO zca_ps_data_map,
    go_exc             TYPE REF TO cx_root.
go_data_agent = zca_ps_data=>agent.
go_data_map_agent = zca_ps_data_map=>agent.
TRY.
Read data mapping with the business key
      go_data_map_ps = go_data_map_agent->get_persistent(
                         i_data_ref     = iv_data_ref
                         i_action       = iv_action ).
... then read the data.
      TRY.
          CALL METHOD go_data_map_ps->get_data_guid
            RECEIVING
              result = go_data_ps.
        CATCH cx_os_object_not_found.
      ENDTRY.
    CATCH cx_root INTO go_exc.
ENDTRY.
<-snip->
At no point during this code are the attributes of the object of the persistent class for the data table populated with the contents of the fields of the data table referenced as the attribute of the mapping table. To clarify, when viewing the object in the debugger all the attributes of the mapping object that are simple table fields are populated with the values of the fields of in the mapping table, however, the attributes of the object that represents the persistent class for the data table are not populated with the fields of the data table. I had hoped that by reading the mapping table object the data object would automatically be populated. Is there another step I need to perform to populate the data object?
I'm sorry if the above is hard to follow. Without being able to provide screenshots it's difficult to explain.
If someone has managed to store references to persistent objects in a table and then read the references back could you list the steps you went through to create the persistent classes and include the code that reads the objects please? The code I have almost works, I must be just missing some subtle point...
Thanks in advance,
Steve.

Hi Andrea,
The iObject being replicated at item level for Service Complaints is the SAP standard behaviour.
Generally we raise complaint refering to some sales or service issues. In your scenario you are trying to create a complaint based on an iObject, then you have to mention the corresponding product details. I dont see any business requirement not to copy the iObject product at the item level.
If you want it then I think only you have to write a Z program for it.
Hope this helps!
Regards,
Chethan

Cloning persistent objects

Does anyone know if ABAP Persistent Objects support cloning?
I can clone the object using a SYSTEM-CALL (though I'd rather not), however that would still mean breaking the rules to set the object key to a new value.
At the moment the only solution appears to be creating a new persistent or transient object via the agent and manually assigning the attributes.

Thanks Uwe. I knew about the SYSTEM-CALL but in this case it does not help.
My problem is that the object key of a persistent object does not appear to be easily modified even from within the object. I want to clone the object and then modify the key to avoid insert collisions.
So far as I can see there is no simple way of modifying the business key of a persistent object.
For now I've implemented IF_OS_CLONE~CLONE in a public method of my persistent object, created a new persistent object and manually assigned the attributes. Unfortunately the code will have to be modified whenever a new attribute is added.

Equality between primitive and persistent objects

Folks,
I have discovered by chance that the KODO Query implementation allows me
to test for equality between an Integer and a persistent object. This is
actually phenomenally useful because it allows me to easily work around
some really inefficient auto-generated SQL (see below).
I couldn't find anything about this feature in the JDO specs. Is it
accidental? Is it supported, or likely to disappear in future versions?
Dave Syer.
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javax.jdo.JDOHelper.getObjectId(bean)Bean-101
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qu=pm.newQuery(ex);
qu.declareParameters("Property id1");
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# to PROPERTY table:
res=qu.execute(bean.getProperty())# resulting SQL:
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# WHERE (t0.PROPERTY_ID = 371 AND t0.PROPERTY_ID =
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qu=pm.newQuery(ex);
qu.declareParameters("java.lang.Integer id1");
qu.setFilter("propertyId == id1")# ...but parameter value is allowed to be a Property -- magically
# turned into an integer when the SQL is generated:
res=qu.execute(bean.getProperty())# resulting SQL:
# SELECT t0.PROPERTY_ID, t0.PROPERTY_ID FROM BEAN t0 WHERE
# t0.PROPERTY_ID = 371

It is accidental and unsupported.Is there any other way to get round the 'unnecessary join' issue that I
mentioned briefly in my original posting? In a real world example, I was
able to improve performance of a single query by a factor of 100 (and my
DB experts tell me there was no way to optimise indexes or anything at the
RDBMS level and achieve the same result).
DAve.

How to use a proxy; xmltype as a constructor

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As some background, I have a field in a database that is a varchar2. The content of this field is an xml fragment (actually xhtml).
My query converts this into an XMLType object by using the XMLType function (as a constructor). To make this into a fragment rooted in a single element, I wrap this in a fresh div.
So far so good. This all works. :-)
This content sometimes contains entity references (like "& gt;" or "& nbsp;").
Oracle could not handle this so I am now includin a DTD DOCTYPE declaration in my XMLType call. I'm using the XHTML 1.0 DTD.
Here's a simplified version of my query:
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Matthew,
Set the OS environment variable for the http proxy server.
There is a metalink note that explains this.

Hashtable with persistent object as key and collection as value

I am trying to use a Hastable with a persistent object as the key and a
collection as the value. A long time ago, Abe White said:
"Kodo currently does not support a map in which the keys are persistent
objects and the values are collections. I think your best bet would be
to create an intermediate class that has a 1-1 relation to the "key" and
a collection of persistent objects for the "value". Then keep a
collection of these intermediate objects. You could use jdoPostLoad and
jdoPreStore to hash/unhash the collection of intermediate objects to/from
a Map if you need to."
So I made an intermediate class, which gave me a Hashtable with a persistent
object as the key and another for the value. Then the one for the value
contains the collection. This works but I'm wondering about the
performance, would this method be slower?
Also it was said that version 3.0 would support this. I'm curious if this
is available in 2.5 or if it's still planned for 3.0.
Thanks
Michael

I'm observing massive performance problems but I didn't think it could be
caused by this intermediary object but maybe that is the problem. For
example if I start a transaction to delete everything (with 3,000 records
which in turn has 3,000 records which in turn has 2 lists each) theprogram
crashes before it can finish the transaction. I then put in some loops to
delete 100 records at a time and this runs but it took over an hour to
delete the 3,000 records.
Do you have any other ideas of how to improve the performance? Are there
any alternatives?I solved the performance problem. I was storing web page content (all the
HTML) in a String which by default is in the default-fetch-group. I had
been thinking this was using lazy-loading but it wasn't. So I put
default-fetch-group=false for this property and now the performance is
great. It makes sense because it was retrieving approximately 5k of text
for each record! When deleting 3,000 records this comes out to be 14 megs.
Moral of the story: Use the default-fetch-group wisely!!

Persistent objects - base table syntax error

I've created a persistent object for a ztable, then the customer has asked me to change the counter field from numc 3 to numc 5, and also remove a field I've done this, and activated and adjusted the table in SE14.
Now, in SE24, I've gone in and adjusted the persistence mapping. When I activate the persistent class, I now get a syntax error in the base class, because it's still referring to components of the old table structure.
When we change the structure of the underlying table, do we have to delete and recreate the persistence classes? Is there a "repair" option?
( It seems it would be useful to have a tool that would generate a basic persistent class directly from a table ).
matt

Hi Matt,
There is no repair option. As far as I'm aware the persistence class builder function doesn't recognise changes to data types unfortunately. In similar circumstances I've solved the problem by deleting and recreating the class. It's not ideal but at least it's a quick process.
Regards,
Steve.

Updation of persistent object

Hi,
I'm using objects persistence. I've created a persistent class and using this for storing data in an index cluster table to use the stored data afterwards.
I've created methods for creating persistent object (using export to database), delete object and read object (using import to database).
But i'm not getting how to use update of existing stored object.
Any help would be appreciated.
Regards
Rajesh

Persistent objects were introduced in ABAP OO in order to replace physical data manipulation via open SQL statements by more abstract OO-typical GET and SET methods for a persistent data object. Has nothing to do with Dequeue/Enqueue.
I recommend reading chapter 3 of [Next Generation ABAP Development|http://www.sappress.com/product.cfm?account=&product=H1986] for the full story.
Greetings
Thomas

Collection of non-persistent objects

Greetings
Is it possible to persist a Collection of non-persistent objects through the
kodo externalization feature? The non-persistent objects themselves are
externalizable, but I don't know how I would go about persisting a
Collection of them.
..droo.

If you store them in some sort of externalized form in a single column it is
easy - just use externalization framework to ext and de-ext them to anf from
string. Couple of caveats you need to be aware of If your collection objects
are mutable:
1. You need to durty your collection field so it get prsisted on commit
2. on rollback Kodo will restore you collection content but not collection
member content. If they are mutable you will have to make their class
persistent with mapping "none" so they participate in transaction
"Drew Lethbridge" <[email protected]> wrote in message
news:BD0B44BF.544%[email protected]..
Greetings
Is it possible to persist a Collection of non-persistent objects throughthe
kodo externalization feature? The non-persistent objects themselves are
externalizable, but I don't know how I would go about persisting a
Collection of them.
.droo.

ObjectId on persistent object

Hello
Using Datastore identity, Is it possible to declare an instance variable on
a persistent object which will "automatically" be populated with the
datastore objectid when the enclosing object is retrieved from persistence?
This would be in preference to always calling JDOHelper.getObjectId(obj)?
[or persistenceManager.getObjectId(obj) ]
Thanks
..droo.

We've done this using the jdoPostLoad callback as follows:
public void jdoPostLoad()
setObjectID(JDOHelper.getObjectId(this).toString());
Scott
Drew Lethbridge wrote:
Hello
Using Datastore identity, Is it possible to declare an instance variable on
a persistent object which will "automatically" be populated with the
datastore objectid when the enclosing object is retrieved from persistence?
This would be in preference to always calling JDOHelper.getObjectId(obj)?
[or persistenceManager.getObjectId(obj) ]
Thanks
..droo.

Need of persistent object

Hi Gurus.,
I am little bit confused over Persistent Objects.. Y we need to use Persistent Objects.. Is it equal to Enquee/Dequee process of normal abap ..
Regards.,
S.Sivakumar

Persistent objects were introduced in ABAP OO in order to replace physical data manipulation via open SQL statements by more abstract OO-typical GET and SET methods for a persistent data object. Has nothing to do with Dequeue/Enqueue.
I recommend reading chapter 3 of [Next Generation ABAP Development|http://www.sappress.com/product.cfm?account=&product=H1986] for the full story.
Greetings
Thomas

Using SequenceFactory getNext in persistent object constructor

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