| EditionDistance always returns 0 distance [message #1819682] |
Tue, 21 January 2020 04:55  |
Eclipse User |
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Hi!
I am working on a project that takes a broken model and repairs it. I am trying to calculate the editing distance between the original model and the repaired version. To do this I am using the org.eclipse.emf.compare.match.eobject.EditionDistance-class.
I am using EMFCompare to find the differenes, and passes the Comparison to the distance-function. Even though there are differences listed in the comparison, the distance is still 0 and the areIdentic-method returns true. Am I using it wrong?
This is the code I am using:
public double calculateDistanceFromOriginal() {
URI originalUri = URI.createFileURI(getOriginal().getAbsolutePath());
URI modelUri = URI.createFileURI(getModel().getAbsolutePath());
ResourceSet originalResourceSet = new ResourceSetImpl();
ResourceSet modelResourceSet = new ResourceSetImpl();
originalResourceSet.getResource(originalUri, true);
modelResourceSet.getResource(modelUri, true);
IComparisonScope scope = new DefaultComparisonScope(originalResourceSet, modelResourceSet, null);
Comparison comparison = EMFCompare.builder().build().compare(scope);
EList<Diff> diff = comparison.getDifferences();
Resource orignalResource = originalResourceSet.getResource(originalUri, false);
Resource modelResource = modelResourceSet.getResource(modelUri, false);
WeightProvider weightProvider = new EcoreWeightProvider();
EditionDistance distanceCalculator = EditionDistance.builder().weightProvider(weightProvider).build();
double totalDistance = 0;
for(int i = 0; i < orignalResource.getContents().size(); i++) {
EObject originalObject = orignalResource.getContents().get(i);
EObject newObject = modelResource.getContents().get(i);
totalDistance += distanceCalculator.distance(comparison, originalObject, newObject);
}
return totalDistance; // distanceCalculator.distance(comparison, originalModel, newModel);
To view the full code, look here.
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| Re: EditionDistance always returns 0 distance [message #1820896 is a reply to message #1820699] |
Fri, 31 January 2020 03:15  |
| Eclipse User |
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Thank you so much for the response :)
You're right, the builder is not used. Like you said you construct it with a WeightProvider registry and an EqualityHelperExtensionProvider registry.
From org.eclipse.emf.compare.match.DefaultMatchEngine:
public static IEObjectMatcher createDefaultEObjectMatcher(UseIdentifiers useIDs,
WeightProvider.Descriptor.Registry weightProviderRegistry,
EqualityHelperExtensionProvider.Descriptor.Registry equalityHelperExtensionProviderRegistry) {
final IEObjectMatcher matcher;
final EditionDistance editionDistance = new EditionDistance(weightProviderRegistry,
equalityHelperExtensionProviderRegistry);
final CachingDistance cachedDistance = new CachingDistance(editionDistance);
switch (useIDs) {
case NEVER:
matcher = new ProximityEObjectMatcher(cachedDistance);
break;
.
.
.
}
As we can see, CachingDistance is used. The ProximityEObjectMatcher passes this to a ByTypeIndex, ant the ByTypeIndex passes it to a ProximityIndex. When looking at the ProximityIndexTest I found this:
Comparison comp = CompareFactory.eINSTANCE.createComparison();
for (EObject leftElement : index.getValuesStillThere(Side.LEFT)) {
assertNull("With a distance which always return Double.MAX_VALUE we should never find a closest.",
index.findClosests(comp, leftElement, Side.LEFT));
}
The findClosest calls the private method findTheClosest(), that is the closest I can find to comparing two models.
I have tried implementing this:
Comparison comparison = CompareFactory.eINSTANCE.createComparison();
EditionDistance editionDistance = new EditionDistance(WeightProviderDescriptorRegistryImpl.createStandaloneInstance(), EqualityHelperExtensionProviderDescriptorRegistryImpl.createStandaloneInstance());
CachingDistance cachingDistance = new CachingDistance(editionDistance);
double distance = cachingDistance.distance(comparison, orignalResource.getContents().get(0), modelResource.getContents().get(0));
System.out.println("Distance: "+ distance);
...but still no luck. The distance is still 0.0, and the models are not equal. Any ideas?
Quote:Why exactly are you trying to compute the distance between the models, shouldn't the comparison then merging be enough to repair your models?
I have already repaired the models, the EditingDistance is just to see how much the models have changed :)
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