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Does ChangeRecorder record inverted ChangeKind about ResourceChange? [message #1149226]

Tue, 22 October 2013 01:44

Hiroki Kondo

Messages: 47
Registered: July 2009

Member

Hi,

I'd like to use ChangeRecorder to recode the changes to the model.
When I ADD a model to resource, ResourceChange#getKind() returns "REMOVE".
Why does it return "REMOVE"? If it correct behavior, how should I use ChangeRecorder?
If ResourceChange is deprecated, What classes should I use?

I wrote a test code about this in JUnit4.

package org.eclipse.emf.ecore.change.util;

import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;

import org.eclipse.emf.common.util.EList;
import org.eclipse.emf.common.util.URI;
import org.eclipse.emf.ecore.EPackage;
import org.eclipse.emf.ecore.EcoreFactory;
import org.eclipse.emf.ecore.change.ChangeDescription;
import org.eclipse.emf.ecore.change.ChangeKind;
import org.eclipse.emf.ecore.change.ListChange;
import org.eclipse.emf.ecore.change.ResourceChange;
import org.eclipse.emf.ecore.resource.Resource;
import org.eclipse.emf.ecore.resource.impl.ResourceImpl;
import org.junit.Test;

public class ChangeRecorderLearningTest {
	
	@Test
	public void addAModelToResource() throws Exception {
		Resource resource = new ResourceImpl(URI.createURI("foo"));
		ChangeRecorder recorder = new ChangeRecorder(resource);
		EcoreFactory factory = EcoreFactory.eINSTANCE;
		EPackage pack = factory.createEPackage();
		resource.getContents().add(pack);
		ChangeDescription description = recorder.endRecording();

		EList<ResourceChange> resourceChanges = description.getResourceChanges();
		for (ResourceChange resourceChange : resourceChanges) {
			EList<ListChange> listChanges = resourceChange.getListChanges();
			for (ListChange listChange : listChanges) {
				assertThat(listChange.getKind(),is(ChangeKind.ADD_LITERAL)); // FAIL
			}
		}
	}
}

Best Regards,

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Re: Does ChangeRecorder record inverted ChangeKind about ResourceChange? [message #1149269 is a reply to message #1149226]

Tue, 22 October 2013 02:24

Ed Merks

Messages: 30825
Registered: July 2009

Senior Member

Hiroki,

Comments below.

On 22/10/2013 3:44 AM, Hiroki Kondo wrote:
> Hi,
>
> I'd like to use ChangeRecorder to recode the changes to the model.
> When I ADD a model to resource, ResourceChange#getKind() returns
> "REMOVE".
> Why does it return "REMOVE"? If it correct behavior, how should I use
> ChangeRecorder?
Keep in mind that a change recorder produces a delta relative to the
current, i.e., final state, of the model so it's a reverse delta if you
want to interpret it relative to the original state of the model. So
yes, every add to the model should produce a remove in the deleta and
every remove from the model should produce an add in the delta.

You can have a look at
org.eclipse.emf.test.core.change.ChangeDescriptionReverseTest.TestHelper.doit()
to see how to compute a forward delta, i.e., like this. So it's
important to call setEObjectToProxyURIMap so it's populated during
change recording and to call copyAndReverse on the description to
reverse it (without actually reversing the changes to the model's state).

abstract class TestHelper
{
void doit() throws Exception
{
ResourceSet originalResourceSet = new ResourceSetImpl();

loadResources(originalResourceSet);

Map<EObject, URI> eObjectToProxyURIMap = new HashMap<EObject, URI>();
ChangeRecorder changeRecorder = new ChangeRecorder();
changeRecorder.setRecordingTransientFeatures(false);
changeRecorder.setEObjectToProxyURIMap(eObjectToProxyURIMap);
changeRecorder.beginRecording(Collections.singleton(originalResourceSet));

makeChanges();

ChangeDescription changeDescription = changeRecorder.endRecording();
changeDescription.copyAndReverse(eObjectToProxyURIMap);

> If ResourceChange is deprecated, What classes should I use?
>
> I wrote a test code about this in JUnit4.
>
>
> package org.eclipse.emf.ecore.change.util;
>
> import static org.hamcrest.CoreMatchers.is;
> import static org.junit.Assert.assertThat;
>
> import org.eclipse.emf.common.util.EList;
> import org.eclipse.emf.common.util.URI;
> import org.eclipse.emf.ecore.EPackage;
> import org.eclipse.emf.ecore.EcoreFactory;
> import org.eclipse.emf.ecore.change.ChangeDescription;
> import org.eclipse.emf.ecore.change.ChangeKind;
> import org.eclipse.emf.ecore.change.ListChange;
> import org.eclipse.emf.ecore.change.ResourceChange;
> import org.eclipse.emf.ecore.resource.Resource;
> import org.eclipse.emf.ecore.resource.impl.ResourceImpl;
> import org.junit.Test;
>
> public class ChangeRecorderLearningTest {
>
> @Test
> public void addAModelToResource() throws Exception {
> Resource resource = new ResourceImpl(URI.createURI("foo"));
> ChangeRecorder recorder = new ChangeRecorder(resource);
> EcoreFactory factory = EcoreFactory.eINSTANCE;
> EPackage pack = factory.createEPackage();
> resource.getContents().add(pack);
> ChangeDescription description = recorder.endRecording();
>
> EList<ResourceChange> resourceChanges =
> description.getResourceChanges();
> for (ResourceChange resourceChange : resourceChanges) {
> EList<ListChange> listChanges =
> resourceChange.getListChanges();
> for (ListChange listChange : listChanges) {
> assertThat(listChange.getKind(),is(ChangeKind.ADD_LITERAL)); // FAIL
> }
> }
> }
> }
>
>
> Best Regards,

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