initial glue code for NIHVIVO-205 'Ontology Upgrade...'

webapp/src/edu/cornell/mannlib/vitro/webapp/ontology/update/OntologyUpdater.java

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+/* $This file is distributed under the terms of the license in /doc/license.txt$ */
+
+package edu.cornell.mannlib.vitro.webapp.ontology.update;
+
+import java.io.InputStream;
+import java.util.List;
+
+import javax.servlet.ServletContext;
+
+import com.hp.hpl.jena.query.Query;
+import com.hp.hpl.jena.query.QueryExecution;
+import com.hp.hpl.jena.query.QueryExecutionFactory;
+import com.hp.hpl.jena.query.QueryFactory;
+import com.hp.hpl.jena.rdf.model.Model;
+import com.hp.hpl.jena.shared.Lock;
+
+import edu.cornell.mannlib.vitro.webapp.dao.jena.OntModelSelector;
+
+/**
+ * Performs knowledge base updates if necessary to align with a
+ * new ontology version.
+ * 
+ * This class assumes that config and mapping data files are available
+ * at DATA_DIR.
+ * 
+ * @author bjl23
+ *
+ */
+public class OntologyUpdater {
+
+	private final String DATA_DIR = "/WEB-INF/ontologies/update/";
+	private final String ASK_QUERY_FILE = DATA_DIR + "ask.sparql";
+	private final String SUCCESS_ASSERTIONS = DATA_DIR + "success.n3";
+	private final String SUCCESS_RDF_FORMAT = "N3";
+	private final String DIFF_FILE = DATA_DIR + "diff.tab.txt";
+	
+	private ServletContext context;
+	private OntModelSelector ontModelSelector;
+	
+	public OntologyUpdater(ServletContext context, 
+			OntModelSelector ontModelSelector) {
+		this.context = context;
+		this.ontModelSelector = ontModelSelector;
+	}
+	
+	public void update() {	
+		// Check to see if the update is necessary.
+		if (updateRequired()) {
+			performUpdate();
+			// add assertions to the knowledge base showing that the 
+			// update was successful, so we don't need to run it again.
+			assertSuccess();
+		}
+	}
+	
+	private void performUpdate() {
+		List<AtomicOntologyChange> changes = getAtomicOntologyChanges();
+		
+		//preprocessChanges(changes);
+		//updateTBox(changes);
+		
+		updateABox(changes);
+		
+		updateAnnotations();
+		
+		// perform additional additions and retractions
+	}
+	
+	private List<AtomicOntologyChange> getAtomicOntologyChanges() {
+		return null; //Anup's code is called here
+	}
+	
+	private void updateABox(List<AtomicOntologyChange> changes) {
+		// perform operations based on change objects
+		// run additional SPARQL CONSTRUCTS 
+
+	}
+	
+	private void updateAnnotations() {
+		// Stella's code is called here
+	}
+	
+	/**
+	 * Executes a SPARQL ASK query to determine whether the knowledge base
+	 * needs to be updated to conform to a new ontology version
+	 */
+	private boolean updateRequired() {
+		String sparqlQueryStr = loadSparqlQuery(ASK_QUERY_FILE);
+		if (sparqlQueryStr == null) {
+			return false;
+		}
+		Model m = ontModelSelector.getApplicationMetadataModel();
+		Query query = QueryFactory.create(sparqlQueryStr);
+		QueryExecution qexec = QueryExecutionFactory.create(query, m);
+		return qexec.execAsk();
+	}
+	
+	/**
+	 * loads a SPARQL ASK query from a text file
+	 * @param filePath
+	 * @return the query string or null if file not found
+	 */
+	private String loadSparqlQuery(String filePath) {
+		return null; // TODO implement me!
+	}
+	
+	private void assertSuccess() {
+	    Model m = ontModelSelector.getApplicationMetadataModel();
+	    InputStream inStream = context.getResourceAsStream(SUCCESS_ASSERTIONS);
+	    m.enterCriticalSection(Lock.WRITE);
+	    try {
+	    	m.read(inStream, SUCCESS_RDF_FORMAT);
+	    } finally {
+	    	m.leaveCriticalSection();
+	    }
+	}
+	
+}