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Subject: Re: AW: [sdo] New HelperProvider implementation
Hi Blaise, You are right. Sorry I missed that. It means that by default we use the default context of the default implementation, instead of just the default context of the one and only implementation previously. I think that we also need to look at how we can allow other implementations to be used. Maybe we should provide more constructors for ExternalizableDelegator, where you can pass in an implementation. public ExternalizableDelegator() { this(SDOImplementation.getInstance()); } public ExternalizableDelegator(Object target) { this(SDOImplementation.getInstance(), target); } public ExternalizableDelegator(SDOImplementation impl) { delegate = impl.resolvable(); } public ExternalizableDelegator(SDOImplementation impl, Object target) { delegate = impl.resolvable(target); } Frank. Blaise Doughan <blaise.doughan@oracle.com> 02/06/2009 10:36 AM To Frank Budinsky/Toronto/IBM@IBMCA cc sdo@lists.oasis-open.org Subject Re: AW: [sdo] New HelperProvider implementation Hi Frank, Along with your proposed changes the following would be required to ExternalizableDelegator (also attached). public ExternalizableDelegator() { delegate = SDOImplementation.getInstance().resolvable(); } public ExternalizableDelegator(Object target) { delegate = SDOImplementation.getInstance().resolvable(target); } I think in general this means that the HelperContext used for deserialization will become: SDOImplementation.getInstance().getDefaultContext(); As opposed to: HelperProvider.getDefaultContext(); -Blaise Frank Budinsky wrote: Hi Guys, Since we'd like to get rid of all the INSTANCE fields for SDO-96, I was thinking that all the static getXXXHelper() methods in HelperProvider should also go. Once we remove all this, I think we're not left with much interesting content in HelperProvider, so I think that maybe we should just deprecate the entire class HelperProvider, and replace it with a clean new API. I've attached my first pass at this, class SDOImplementation. I've deprecated HelperProvider, but made it a subclass of SDOImplementation, for backward compatibility. Comments welcome. Thanks, Frank. Frank Budinsky/Toronto/IBM@IBMCA 01/13/2009 10:51 AM To sdo@lists.oasis-open.org cc Subject Re: AW: [sdo] New HelperProvider implementation Hi Ron, Thanks for looking at it. You're right that is is a partial resolution to SDO-96. My thinking was that SDO-96 is one of the issues that we can resolve in the virtual F2F, but I wanted to get some starting material for discussion on the table before that. I think there are several aspects to the issue that we'll want to discuss in detail. One thing that I definitely had intended this class to do, but forgot, was to allow more that one impl/service to be located. I've attached a slightly modified version here. Thanks, Frank. "Barack, Ron" <ron.barack@sap.com> 01/13/2009 10:01 AM To Frank Budinsky/Toronto/IBM@IBMCA, <sdo@lists.oasis-open.org> cc Subject AW: [sdo] New HelperProvider implementation Hi Frank, I'm guessing that this is a partial resolution to SDO-96, is that right? If not, what is the issue that is being addressed here. I think holding the information in a file in meta-inf is OK, certainly an improvement over what we have now, but in order to handle the bootstrapping problem, I think we need some additional options. The problem with having things in a file in meta-inf is that it doesn't really change the situation about having only one SDO on the classpath, which the user always gets, no matter what. A lot of systems allow specifying the implementation class through the API... InitialContext is a famous example of this. Others allow configuration through system properties ("-D"s). I think SDO should allow for all 3 configuration options, with the API given highest priority, System properties second, the mechanism which you provide third, and the fallback solution should be the fixed class name constant, as you have given it. Best Regards, Ron -----Ursprüngliche Nachricht----- Von: Frank Budinsky [mailto:frankb@ca.ibm.com] Gesendet: Montag, 12. Januar 2009 22:57 An: sdo@lists.oasis-open.org Betreff: [sdo] New HelperProvider implementation Hi Guys, Attached is a proposed new implementation for class HelperProvider. The advantages of this impl are: 1. It allows SDO implementations be registered as a Java Service Provider - http://java.sun.com/j2se/1.4.2/docs/guide/jar/jar.html#Service%20Provider 2. Implementations should not need to replace this impl, but instead simply plug in an subclass with necessary overrides. 3. I believe it's backward compatible with the previous version. Please take a look at this impl, and let me know what you think. Maybe we can discuss in tomorrow's call? Thanks, Frank. --------------------------------------------------------------------- To unsubscribe from this mail list, you must leave the OASIS TC that generates this mail. Follow this link to all your TCs in OASIS at: https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php [attachment "HelperProvider.java" deleted by Frank Budinsky/Toronto/IBM] --------------------------------------------------------------------- To unsubscribe from this mail list, you must leave the OASIS TC that generates this mail. Follow this link to all your TCs in OASIS at: https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php --------------------------------------------------------------------- To unsubscribe from this mail list, you must leave the OASIS TC that generates this mail. Follow this link to all your TCs in OASIS at: https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php /** * <copyright> * * Service Data Objects * Version 2.1.1 * Licensed Materials * * (c) Copyright BEA Systems, Inc., International Business Machines Corporation, * Oracle Corporation, Primeton Technologies Ltd., Rogue Wave Software, SAP AG., * Software AG., Sun Microsystems, Sybase Inc., Xcalia, Zend Technologies, * 2005-2008. All rights reserved. * * </copyright> * */ package commonj.sdo.impl; import java.io.Externalizable; import java.io.IOException; import java.io.ObjectInput; import java.io.ObjectOutput; import java.io.ObjectStreamException; /** * Delegates DataObject serialization while ensuring implementation independent * java.io.Serialization. An implementation of DataObject * returns an ExternalizableDelegator from its writeReplace() method. * * The root DataObject is the object returned from do.getRootObject() where * do is the DataObject being serialized in a java.io.ObjectOutputStream. * When do.getContainer() == null then do is a root object. * * The byte format for each DataObject in the stream is: * [0] [path] [root] // when do is not a root object * [1] [rootXML] // when do is a root object * * where: * [0] is the byte 0, serialized using writeByte(0). * [1] is the byte 1, serialized using writeByte(1). * * [path] is an SDO path expression from the root DataObject to the serialized * DataObject such that root.getDataObject(path) == do. * Serialized using writeUTF(path). * * [root] is the root object serialized using writeObject(root). * * [rootXML] is the GZip of the XML serialization of the root DataObject. * The XML serialization is the same as * XMLHelper.INSTANCE.save(root, "commonj.sdo", "dataObject", stream); * where stream is a GZIPOutputStream, length is the number of bytes * in the stream, and bytes are the contents of the stream. * Serialized using writeInt(length), write(bytes). * */ public class ExternalizableDelegator implements Externalizable { public interface Resolvable extends Externalizable { Object readResolve() throws ObjectStreamException; } static final long serialVersionUID = 1; transient Resolvable delegate; public ExternalizableDelegator() { delegate = SDOImplementation.getInstance().resolvable(); } public ExternalizableDelegator(Object target) { delegate = SDOImplementation.getInstance().resolvable(target); } public void writeExternal(ObjectOutput out) throws IOException { delegate.writeExternal(out); } public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException { delegate.readExternal(in); } public Object readResolve() throws ObjectStreamException { return delegate.readResolve(); } }
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