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EMF Query2 questions [message #672549]

Sat, 21 May 2011 17:34

No real name

Messages: 11
Registered: May 2011

Junior Member

Hello,

i hope you can help me, i have some questions about emf query2, sadly i don't found directly information about it, first the "none-code" questions:
- So far i have seen somewhere, EMF-Query2 will released with the next eclipse relase, is that correct?
- Will Query2 replace Query1, or coexist?

Code-Questions:
At time i am working on a 'project' limted in time, and the question is should i use query1 or query2. At time query1 seem easier to me, for a person who is new in working with EMF, with SELECT(), FROM() and so on. Sadly i don't get query2 to run at time, perhaps you could help me out here. I read some post here about query2 and take a look in "org.eclipse.emf.query2.lilbrarytest", it seem really difficult to me. I thoguht it would be more like: create a index and pass simple the URI's which i want to query and simple make my query statements and execute them with the index. Well, i hope you could help me out, now the code:

public class EMFQuery2 {
	private static Index index = null;
	public static void main(String[] args) {
		index = IndexFactory.getInstance();
		index.executeUpdateCommand(new UpdateCommandAdapter() {
				@Override
				public void execute(final IndexUpdater updater) {
					ResourceIndexer indexer = new ResourceIndexer();
					indexer.resourceChanged(updater, EcorePackage.eINSTANCE.eResource());
					indexer.resourceChanged(updater, WebpagePackage.eINSTANCE.eResource());
					
					ResourceSet rs = new ResourceSetImpl();
					loadResources(rs);
					
					EList<Resource> list = rs.getResources();
					indexer.resourceChanged(updater, list.toArray(new Resource[list.size()]));
					
					for(Resource r: list) {
						r.unload();
					}
				}
			});
		
		// LibraryTransformation.java
		if (!Platform.isRunning()) {
			new org.eclipse.emf.mwe.utils.StandaloneSetup().setPlatformUri("..");
		}
		
		Injector injector = new QueryStandaloneSetup().createInjectorAndDoEMFRegistration();
		XtextResourceSet set = injector.getInstance(XtextResourceSet.class);
		set.addLoadOption(XtextResource.OPTION_RESOLVE_ALL, Boolean.TRUE);
		URI resourceURI = URI.createURI("platform:/plugin/de.vogella.emf.webpage.usingmodel/selects.query");
		URI normalizedURI = set.getURIConverter().normalize(resourceURI);
		LazyLinkingResource xtextResource = (LazyLinkingResource)set.getResource(normalizedURI, true);
		
		Model model = (Model) xtextResource.getContents().get(0);
		
		EList<NamedQuery> queryList = model.getNamedQueries();
		
		for (NamedQuery query: queryList) {
			ResourceSet rs = new ResourceSetImpl();
			Query select = QueryTransformer.transform(query.getQuery());
			System.out.println("Queryname: "+ query.getName());
			System.out.println("select.toString: "+ select.toString().trim());
			
			QueryProcessor queryProcessor = QueryProcessorFactory.getDefault().createQueryProcessor(index);
			// ResultSet result = queryProcessor.execute("from ...", getQueryContext(rs));
			ResultSet result = queryProcessor. execute(select, getQueryContext(rs));
			
			System.out.println("size: "+ result.getSize() +"\n\n");
			System.out.println(result);
		}
	}

	private static QueryContext getQueryContext(final ResourceSet rs) {
		return new QueryContext() {

			public URI[] getResourceScope() {
				final List<URI> result = new ArrayList<URI>();
				index.executeQueryCommand(new QueryCommand() {
					public void execute(QueryExecutor queryExecutor) {
						ResourceQuery<ResourceDescriptor> resourceQuery = IndexQueryFactory.createResourceQuery();
						for (ResourceDescriptor desc : queryExecutor.execute(resourceQuery)) {
							result.add(desc.getURI());
						}
					}
				});
				return result.toArray(new URI[0]);
			}
			public ResourceSet getResourceSet() {
				return rs;
			}
		};
	}
	
	public static void loadResources(ResourceSet rs) {
		// @see load()
		WebpagePackage wp = WebpagePackageImpl.init();
		EPackage.Registry reg = rs.getPackageRegistry();
		reg.put(wp.getNsURI(), wp);
		
		URI loadURI = URI.createFileURI("save.xml");
		Resource resource = rs.getResource(loadURI, true);
		try {
			resource.load(null);
		} catch (IOException e) {
			System.out.println("EMFQuery2.loadResourcesl()");
			e.printStackTrace();
		}
	}

}

And i don't understand the meaning of index.executeUpdateCommand() [and index.executeQueryCommand()], same for the getQueryContext() method i copied. Did i miss some basics here?

By executing the code i get following Exception:

Exception in thread "main" com.google.inject.internal.ComputationException: com.google.inject.internal.ComputationException: java.lang.NoClassDefFoundError: org/eclipse/xtext/util/TextLocation

But i can't find in which plugin it is located, i have try every *.xtext.* plugin.

Thanks for any help,
littleRathi

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