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[CDO]How to get different revision of a resource? [message #763808]

Sat, 10 December 2011 16:17

Khosro Asgharifard Sharabiani

Messages: 35
Registered: December 2011

Member

Hi,
I use CDO 4.0 ,Eclipse 3.7.
The following code inserts my model instances to repository :

	try {
		
		transaction = cdoSession.openTransaction();
		resource = transaction.getOrCreateResource("/res1");
			Library library = LibraryFactory.eINSTANCE.createLibrary();
			library.setName("Something");
			library.setSYSTEM("Tamin");
			Book book = LibraryFactory.eINSTANCE.createBook();
			book.setTitle("Eclipse Modeling Framework (2nd edition)");
			library.getBooks().add(book);
			resource.getContents().add(library);
			transaction.commit();
			cdoSession.close();

		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			cdoSession.close();
		}

And then i update book instance by the following code(so that ,another row inserted to Book table in repository(Database)) :

	public void updateRepository() {

		
		transaction = cdoSession.openTransaction();
		resource = transaction.getOrCreateResource("/res1");
		List<EObject> eObjects = resource.getContents();
		for (EObject eObject : eObjects) {
			LibraryImpl libraryImpl = (LibraryImpl) eObject;
			libraryImpl.getBooks().get(0).setTitle("Eclipse Modeling Framework (3nd edition)");
		}
		try {
			transaction.commit();
		} catch (CommitException e) {
			e.printStackTrace();
		} finally {
			cdoSession.close();
		}
	}

And my cdo-server.xml :

 
<cdoServer>
 
    <acceptor type="tcp" listenAddr="0.0.0.0" port="2036">
    </acceptor>
 
    <repository name="demo">
 <property name="ensureReferentialIntegrity" value="true"/>
 	<property name="supportingAudits" value="true"/>
	<property name="supportingBranches" value="true"/>
 	<property name="supportingEcore" value="true"/>
        <store type="db">
            <mappingStrategy type="horizontal"/>
            <dbAdapter name="mysql"/>
            <dataSource
                class="com.mysql.jdbc.jdbc2.optional.MysqlDataSource"
                url="jdbc:mysql://localhost:3306/cdotest?createDatabaseIfNotExist=true"
                user="root"
                password="123456"
                />
        </store>
    </repository>
 
</cdoServer>

Now How can i programmatically(by writing code) get revision of a Library and Book models and print their attributes(EAttribute) to console?

I hope that my question is clear.

Khosro.

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Re: [CDO]How to get different revision of a resource? [message #763852 is a reply to message #763808]

Sat, 10 December 2011 18:26

Eike Stepper

Messages: 6682
Registered: July 2009

Senior Member

Am 10.12.2011 17:18, schrieb Khosro Asgharifard Sharabiani:
> Hi,
> I use CDO 4.0 ,Eclipse 3.7.
> The following code inserts my model instances to repository :
>
>
> try {
>
> transaction = cdoSession.openTransaction();
> resource = transaction.getOrCreateResource("/res1");
> Library library = LibraryFactory.eINSTANCE.createLibrary();
> library.setName("Something");
> library.setSYSTEM("Tamin");
> Book book = LibraryFactory.eINSTANCE.createBook();
> book.setTitle("Eclipse Modeling Framework (2nd edition)");
> library.getBooks().add(book);
> resource.getContents().add(library);
> transaction.commit();
> cdoSession.close();
>
> } catch (Exception e) {
> e.printStackTrace();
> } finally {
> cdoSession.close();
> }
>
>
> And then i update book instance by the following code(so that ,another row inserted to Book table in
> repository(Database)) :
>
>
>
> public void updateRepository() {
>
>
> transaction = cdoSession.openTransaction();
> resource = transaction.getOrCreateResource("/res1");
> List<EObject> eObjects = resource.getContents();
> for (EObject eObject : eObjects) {
> LibraryImpl libraryImpl = (LibraryImpl) eObject;
> libraryImpl.getBooks().get(0).setTitle("Eclipse Modeling Framework (3nd edition)");
> }
> try {
> transaction.commit();
> } catch (CommitException e) {
> e.printStackTrace();
> } finally {
> cdoSession.close();
> }
> }
>
>
>
> And my cdo-server.xml :
>
>
> <cdoServer>
>
> <acceptor type="tcp" listenAddr="0.0.0.0" port="2036">
> </acceptor>
>
> <repository name="demo">
> <property name="ensureReferentialIntegrity" value="true"/>
> <property name="supportingAudits" value="true"/>
> <property name="supportingBranches" value="true"/>
> <property name="supportingEcore" value="true"/>
> <store type="db">
> <mappingStrategy type="horizontal"/>
> <dbAdapter name="mysql"/>
> <dataSource
> class="com.mysql.jdbc.jdbc2.optional.MysqlDataSource"
> url="jdbc:mysql://localhost:3306/cdotest?createDatabaseIfNotExist=true"
> user="root"
> password="123456"
> />
> </store>
> </repository>
>
> </cdoServer>
>
>
>
> Now How can i programmatically(by writing code) get revision of a Library and Book models and print their
> attributes(EAttribute) to console?
>
> I hope that my question is clear.
Crystal clear ;-)

There's a low-level API to access arbitrary revisions: CDORevisionManager, i.e. session.getRevisionManager(). But on the
CDORevision layer navigation is not directly possible.

If you want to access the entire object graph at a different, historical time it's more convenient to open a CDOView on
the same session and set the (target) timestamp. You can do that when opening the view or even later via setTimeStamp().
A CDOView has a getObject(T) method that you can use to directly jump to an object from another view (your transaction
in this case).

Does that help?

Cheers
/Eike

----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper

Cheers
/Eike

----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper

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Re: [CDO]How to get different revision of a resource? [message #764022 is a reply to message #763852]

Sun, 11 December 2011 06:00

Khosro Asgharifard Sharabiani

Messages: 35
Registered: December 2011

Member

Thanks Eike,
Some questions :
1.I really do not find any proper method(Maybe i am wrong in finding it) in CDOView to get all of model instances in a given timestamp,except that getObject(CDOID id) (as you said),and also we must provide a CDOID to getObject(CDOID id).But i do not know how to provide CDOID.I think it would be better to have a method like "getAllObject()" that returns List of object in a given timestamp.
In order to access entire object graph via CDOView i must know the CDOID of Library instance and then get it by getObject and then get Book instances(Library and Book have dependency) via Library and so on.
But how to access the another instances that have not dependency to Library instance(Again i must know CDOID of that model instance)?

2.I think timestamp is not proper way to get model instances.Because maybe we do not exactly remember when we committed our models to repository(so that we do not know timestamp).
it would be better to use revision number to get model instances from repository.
I saw a cdo_version column in Library and Book tables,but i do not know how to play with them to get all object graph in a revision number(For example revision number 2).

Khosro.

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Re: [CDO]How to get different revision of a resource? [message #764030 is a reply to message #764022]

Sun, 11 December 2011 06:31

Eike Stepper

Messages: 6682
Registered: July 2009

Senior Member

<html>
<head>
<meta content="text/html; charset=UTF-8" http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
Am 11.12.2011 07:00, schrieb Khosro Asgharifard Sharabiani:
<blockquote cite="mid:jc1gtl$5rs$1@news.eclipse.org" type="cite">Thanks
Eike,
 
Some questions : 1.I really do not find any proper method(Maybe i
am wrong in finding it) in CDOView to get all of model instances
in a given timestamp,</blockquote>
Think of a CDOView as a read-only transaction, it has most of the
(same) methods for accessing models. In fact a CDOTransaction is a
sub type of a CDOView. In addition it *has* the (target) timestamp
information so that historical model access itself is in no way
different from latest model access. The same application code could
can be used. 
 
<blockquote cite="mid:jc1gtl$5rs$1@news.eclipse.org" type="cite">except
that getObject(CDOID id) (as you said),and also we must provide a
CDOID to getObject(CDOID id).But i do not know how to provide
CDOID.</blockquote>
No, there is: 
 
<title></title>




<div class="java" align="left">
<table bgcolor="#ffffff" border="0" cellpadding="3"
cellspacing="0">
<tbody>
<tr>
 <td align="left" nowrap="nowrap"
valign="top"> <code>
 /** 
 * Takes an object from a (possibly) different view and contextifies it for the usage with this view. 
 * <ul> 
 * <li>If the given object is contained in this view it is returned unmodified. 
 * <li>If the given object can not be cast to {@link CDOObject} it is returned unmodified. 
 * <li>If the view of the given object is contained in a different session an <code>IllegalArgumentException</code> is 
 * thrown. 
 * <li>If <code>null</code> is passed <code>null</code> is returned. 
 * </ul> 
 */ 
 public <T extends EObject> T getObject(T objectFromDifferentView);</code>
</td>
 </tr>
</tbody>
</table>
</div>


 
which you can use to "beam" an existing transactional object back in
time and use the resulting object as a start point for (historical)
model navigation. 
<style type="text/css">
</style>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 
<blockquote cite="mid:jc1gtl$5rs$1@news.eclipse.org" type="cite">I
think it would be better to have a method like "getAllObject()"
that returns List of object in a given timestamp.
 
</blockquote>
That would have two disadvantages: 
1) A list of all objects would not scale 
2) Historical model access would be incompatible with latest model
access 
 
 
<blockquote cite="mid:jc1gtl$5rs$1@news.eclipse.org" type="cite">In
order to access entire object graph via CDOView i must know the
CDOID of Library instance </blockquote>
You know it because you have a pointer to it in your CDOTransaction.
But the already mentioned <code>getObject(T objectFromDifferentView)</code> method is even more convenient.
You can also load the historical resource by getResource(String path)
and navigate from there. 
 
<blockquote cite="mid:jc1gtl$5rs$1@news.eclipse.org" type="cite">and
then get it by getObject and then get Book instances(Library and
Book have dependency) via Library and so on.
 
But how to access the another instances that have not dependency
to Library instance(Again i must know CDOID of that model
instance)?
 
</blockquote>
How would you access those in a non-historical view (i.e., a
transaction)? 
 
<blockquote cite="mid:jc1gtl$5rs$1@news.eclipse.org" type="cite">
 
2.I think timestamp is not proper way to get model
instances.Because maybe we do not exactly remember when we
committed our models to repository(so that we do not know
timestamp).
 
it would be better to use revision number to get model instances
from repository.
 
</blockquote>
The commit timestamp *is* the revision number (in SVN terminology).
It is returned by each commit operation: 
 
 CDOCommitInfo commitInfo1 = transaction.commit(); 
 long t1 = commitInfo1.getTimeStamp(); 
 CDOView view = transaction.getSession().openView(t1); 
 
<blockquote cite="mid:jc1gtl$5rs$1@news.eclipse.org" type="cite">I
saw a cdo_version column in Library and Book tables,but i do not
know how to play with them to get all object graph in a revision
number(For example revision number 2).
 
</blockquote>
CDORevision.getVersion() is *not* the identifier for an entire
commit changeset or a consistent baseline in the repository. It only
has a meaning in the context of a particular object. 
 
Cheers 
/Eike 
 
---- 
<a class="moz-txt-link-freetext" href="http://www.esc-net.de">http://www.esc-net.de</a> 
<a class="moz-txt-link-freetext" href="http://thegordian.blogspot.com">http://thegordian.blogspot.com</a> 
<a class="moz-txt-link-freetext" href="http://twitter.com/eikestepper">http://twitter.com/eikestepper</a> 
 
 
</body>
</html>

Cheers
/Eike

----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper

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Re: [CDO]How to get different revision of a resource? [message #764049 is a reply to message #764030]

Sun, 11 December 2011 07:45

Khosro Asgharifard Sharabiani

Messages: 35
Registered: December 2011

Member

>>which you can use to "beam" an existing transactional object back in time and use the resulting object as a start point for (historical) model navigation.

What do you mean of existing transactional object?But i do not any any of them when i open a CDOView,or when i open a transaction,look at the following code.

                 CDOTransaction transaction = cdoSession.openTransaction();
                CDOView cdoView = cdoSession.openView();
		cdoView.setTimeStamp(1323531227347L);
		cdoView.getObject(T objectFromDifferentView)
/*Here, i do not have any objectFromDifferentView.
*/

>You can also load the historical resource by getResource(String path) and navigate from there.

Oh,I think this is my solution.Maybe this is a good option.Let me try it.

At last ,i think CDOView for historical navigation in object graph usage is only when we commit a object to repository and in the same time we can use the committed object for navigation.Something like the following code (Am i right?) :

	public void InsertAndNavigate() {
		try {
			// CDOUtil.setLegacyModeDefault(true);

			Library library = LibraryFactory.eINSTANCE.createLibrary();
			library.setName("OtherThing");
			library.setSYSTEM("Tamin");

			library.Book book = LibraryFactory.eINSTANCE.createBook();
			book.setTitle("Java Complete Reference");
			library.getBooks().add(book);
			resource.getContents().add(library);
			transaction.commit();

			CDOView cdoView = cdoSession.openView();
			cdoView.setTimeStamp(1323531227347L);
			Library library2 = cdoView.getObject(library);
			// Then navigate on object graph

			cdoSession.close();

		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			cdoSession.close();
		}
	}

Khosro.

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Re: [CDO]How to get different revision of a resource? [message #764058 is a reply to message #764049]

Sun, 11 December 2011 08:10

Eike Stepper

Messages: 6682
Registered: July 2009

Senior Member

Am 11.12.2011 08:45, schrieb Khosro Asgharifard Sharabiani:
> [...]
>> You can also load the historical resource by getResource(String path) and navigate from there.
>
> Oh,I think this is my solution.Maybe this is a good option.Let me try it.
>
>
> At last ,i think CDOView for historical navigation in object graph usage is only when we commit a object to repository
> and in the same time we can use the committed object for navigation.Something like the following code (Am i right?) :
>
> public void InsertAndNavigate() {
> try {
> // CDOUtil.setLegacyModeDefault(true);
>
> Library library = LibraryFactory.eINSTANCE.createLibrary();
> library.setName("OtherThing");
> library.setSYSTEM("Tamin");
>
> library.Book book = LibraryFactory.eINSTANCE.createBook();
> book.setTitle("Java Complete Reference");
> library.getBooks().add(book);
> resource.getContents().add(library);
Ok.

> transaction.commit();
>
> CDOView cdoView = cdoSession.openView();
> cdoView.setTimeStamp(1323531227347L);
Or better:

long commitTime = transaction.commit();
CDOView cdoView = cdoSession.openView(commitTime);

> Library library2 = cdoView.getObject(library);
> // Then navigate on object graph
>
> cdoSession.close();
Superfluous, see finally block below.

>
> } catch (Exception e) {
> e.printStackTrace();
> } finally {
> cdoSession.close();
> }
> }
Cheers
/Eike

----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper

Cheers
/Eike

----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper

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