tuscany-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Yang ZHONG" <leiwang.yangzh...@gmail.com>
Subject Re: DataObject/DataGraph Serialization & DataGraphRoot
Date Fri, 25 Aug 2006 21:20:00 GMT
You may need to serialize the generated SDO metadata. On the other hand, I
recommend the scenario design to be reconsidered.

Thank Frank for suggesting a SDOUtil helper taking a list of Types for DAS
to serialize all generated Types along with DataGraph.
If you're willing to do that, I'll implement and send it out.

At the same time, I have some thoughts on the scenario design. DataBase
schema is unlikely changed frequently, it's inefficient for DAS to always
generate same SDO metadata over and over again on every single query, it's
also inefficient to serialize same SDO metadata over and over again on every
single invocation back to client. A typical customer scenario is, both
client and server have SDO metadata already, therefore SDO metadata
serialization isn't really necessary, and SDO metadata generation from DAS
isn't really necessary. I know an early version of DAS (it was under
different name) can accept existing SDO metadata and generate only SDO
instances. My previous product customers actually complained about the very
poor performance caused by repeating same SDO metadata generation and
serialization.

So, are you interested in trying such scenario so that you won't have "type
not found" problem?

Solution 2-1 (typical real scenario):
1. deploy SDO metadata to both client and server
2. instruct DAS to accept the existing SDO metadata
3. do rest of whatever being done right now

Solution 2-2 (temporary if current DAS doesn't take any SDO metadata yet)
1. deploy the generated SDO metadata from DAS to client, once
2. do rest of whatever being done right now

On 8/25/06, Kevin Williams <kevincbw@qwest.net> wrote:
>
> The RDB DAS creates the graph and corresponding Types dynamically from
> the database query results.
>
> Frank Budinsky wrote:
>
> >The problem seems to be that the metadata for class DataGraphRoot is not
> >registered on the client. Is that the only missing metadata? What about
> >the metadata for the rest of the model. I can't provide any more help
> >without more details about how the metadata is being defined.
> >
> >Frank.
> >
> >"Kevin Williams" <kevincbw@qwest.net> wrote on 08/25/2006 03:30:15 PM:
> >
> >
> >
> >>It may be that your remote client has not initialized the SDO/EMF
> >>environment properly and I think that we need some help from the SDO
> >>team.  I have copied this to the dev list since not everyone has
> >>registered yet for the user list.
> >>
> >>--Kevin
> >>
> >>
> >>
> >>Luciano Resende wrote:
> >>
> >>
> >>
> >>>Hi Scott
> >>>
> >>>   So, here is a quick example from our unit testings :
> >>>
> >>>    /**
> >>>     * Read a specific customer
> >>>     */
> >>>    public void testReadSingle() throws Exception {
> >>>
> >>>        //Create and initialize command to read customers
> >>>        DAS das = DAS.FACTORY.createDAS(getConnection());
> >>>        Command readCustomers = das.createCommand("select * from
> >>>CUSTOMER where ID = 1");
> >>>
> >>>        //Read
> >>>        DataObject root = readCustomers.executeQuery();
> >>>
> >>>        //Verify
> >>>        assertEquals(1, root.getInt("CUSTOMER[1]/ID"));
> >>>    }
> >>>
> >>>If you get a reference to root first, then try to access the customer
> >>>information, do you still have this problem ?
> >>>
> >>>Maybe something like this :
> >>>
> >>>DataObject root = readCust.executeQuery();
> >>>cust = root.getDataObject("CUSTOMER")
> >>>
> >>>Please let me know if this helps...
> >>>
> >>>- Luciano
> >>>
> >>>
> >>>On 8/24/06, *Scott Kurinskas* <scott.kurinskas@gemstone.com
> >>><mailto:scott.kurinskas@gemstone.com>> wrote:
> >>>
> >>>    Hi,
> >>>
> >>>    Now that my DAS example is up and running, I'm trying to move my
> >>>    example to
> >>>    a client/server environment and integrate it with my product.  My
> >>>    use-case
> >>>    is very simple, a client makes a request to the server, the server
> >>>    fetches
> >>>    the result from the database and returns the DataObject back to
> >>>    the client.
> >>>    The server side code looks like the following:
> >>>
> >>>    das = DAS.FACTORY.createDAS(getConfig("CompanyConfig.xml"),
> >>>    connection);
> >>>    String sql = "Select * from customers where
> >>>    customers.customerNumber = " +
> >>>    key;
> >>>    Command readCust = das.createCommand(sql);
> >>>    DataObject cust = readCust.executeQuery();
> >>>    return cust;
> >>>
> >>>    The code executes fine on the client but for some reason the
> >>>    client is
> >>>    throwing the exception below.  The client should be deserializing
> >>>
> >>>
> >the
> >
> >
> >>>    response into a DataObject, but for some reason its complaining
> >>>    about class
> >>>    DataGraphRoot not found.  The same code executing in a app works
> >>>    great.
> >>>
> >>>    Thoughts?
> >>>
> >>>    Thanks again,
> >>>    Scott
> >>>
> >>>    Caught unexpected Exception
> >>>    org.eclipse.emf.ecore.resource.Resource$IOWrappedException: Class
> >>>    'DataGraphRoot' not found.
> >>>    ( file:///C:/Documents%20and%20Settings/skurinsk/workspace/SDO%20
> >>>    <file:///C:/Documents%20and%20Settings/skurinsk/workspace/SDO%
> >>>
> >>>
> >>20&%20Cache%20
> >>
> >>
> >>>    <file:///C:/Documents%20and%20Settings/skurinsk/workspace/SDO%
> >>>
> >>>
> >>20&%20Cache%20>
> >>
> >>
> >>>    Client/all.datagraph> &%20Cache%20Client/all.datagraph, 5, 22)
> >>>    at
> >>>    org.eclipse.emf.ecore.xmi.impl.XMLLoadImpl.
> >>>
> >>>
> >>handleErrors(XMLLoadImpl.java:80)
> >>
> >>
> >>>    at
> >>>    org.eclipse.emf.ecore.xmi.impl.XMLLoadImpl.load(XMLLoadImpl.java
> >>>
> >>>
> >:189)
> >
> >
> >>>    at
> >>>    org.apache.tuscany.sdo.util.
> >>>
> >>>
> >>DataGraphResourceFactoryImpl$DataGraphResourceIm
> >>
> >>
> >>>    pl$LoadImpl.load(DataGraphResourceFactoryImpl.java:452)
> >>>    at
> >>>    org.eclipse.emf.ecore.xmi.impl.XMLResourceImpl.
> >>>
> >>>
> >>doLoad(XMLResourceImpl.java
> >>
> >>
> >>>    :1
> >>>    79)
> >>>    at
> >>>    org.eclipse.emf.ecore.resource.impl.ResourceImpl.
> >>>
> >>>
> >>load(ResourceImpl.java:1089
> >>
> >>
> >>>    )
> >>>    at
> >>>    org.apache.tuscany.sdo.impl.
> >>>
> >>>
> >>DataGraphImpl$EDataGraphExternalizable.readExter
> >>
> >>
> >>>    nal(DataGraphImpl.java:665)
> >>>    at
> >>>
> >>>
> >>>
> >java.io.ObjectInputStream.readExternalData(ObjectInputStream.java:1758)
> >
> >
> >>>    at
> >>>    java.io.ObjectInputStream.
> >>>
> >>>
> >>readOrdinaryObject(ObjectInputStream.java:1716)
> >>
> >>
> >>>    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java
> >>>
> >>>
> >:1304)
> >
> >
> >>>    at
> >>>
> >>>
> >java.io.ObjectInputStream.readObject(ObjectInputStream.java:349)
> >
> >
> >>>    at
> >>>    org.apache.tuscany.sdo.helper.
> >>>
> >>>
> >>HelperProviderImpl$ResolvableImpl.readDataObje
> >>
> >>
> >>>    ct(HelperProviderImpl.java:205)
> >>>    at
> >>>    org.apache.tuscany.sdo.helper.
> >>>
> >>>
> >>HelperProviderImpl$ResolvableImpl.readExternal
> >>
> >>
> >>>    (HelperProviderImpl.java:144)
> >>>    at
> >>>    commonj.sdo.impl.ExternalizableDelegator.
> >>>
> >>>
> >>readExternal(ExternalizableDelegato
> >>
> >>
> >>>    r.java:80)
> >>>    at
> >>>
> >>>
> >>>
> >java.io.ObjectInputStream.readExternalData(ObjectInputStream.java:1758)
> >
> >
> >>>    at
> >>>    java.io.ObjectInputStream.
> >>>
> >>>
> >>readOrdinaryObject(ObjectInputStream.java:1716)
> >>
> >>
> >>>    at
> >>>
> >>>
> >java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1304)
> >
> >
> >>>    at
> >>>
> >>>
> >java.io.ObjectInputStream.readObject(ObjectInputStream.java:349)
> >
> >
> >>>    at
> >>>
> >>>
> >>>
> >com.gemstone.gemfire.DataSerializer.readObject(DataSerializer.java:3200)
> >
> >
> >>>    at
> >>>    com.gemstone.gemfire.internal.util.BlobHelper.
> >>>
> >>>
> >>deserializeBlob(BlobHelper.jav
> >>
> >>
> >>>    a:55
> >>>
> >>>
> >>>
> >>>
> >>>--
> >>>-----------------------------------------------------
> >>>Luciano Resende
> >>>SOA Opensource - Apache Tuscany
> >>>-----------------------------------------------------
> >>>
> >>>
> >>
> >>
> >>---------------------------------------------------------------------
> >>To unsubscribe, e-mail: tuscany-user-unsubscribe@ws.apache.org
> >>For additional commands, e-mail: tuscany-user-help@ws.apache.org
> >>
> >>
> >>
> >
> >
> >---------------------------------------------------------------------
> >To unsubscribe, e-mail: tuscany-user-unsubscribe@ws.apache.org
> >For additional commands, e-mail: tuscany-user-help@ws.apache.org
> >
> >
> >
> >
> >
> >
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: tuscany-user-unsubscribe@ws.apache.org
> For additional commands, e-mail: tuscany-user-help@ws.apache.org
>
>


-- 

Yang ZHONG

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message