VIVO-909 add isEquivalentGraph() to the RDFService interface.

Moves the test for isIsomorpic() to within the RDFService implementation,
so we can handle the "broken" cases like Virtuoso and TDB. This way seems
to be cleaner than the TripleStoreQuirks approach that I was fooling around with.

webapp/src/edu/cornell/mannlib/vitro/webapp/modules/tripleSource/TripleSource.java

@@ -24,7 +24,4 @@ public interface TripleSource extends Application.Module{
 
 	OntModelCache getShortTermOntModels(RDFService shortTermRdfService,
 			OntModelCache longTermOntModelCache);
-
-	/** Ways in which this TripleSource behaves oddly. */
-	TripleStoreQuirks getQuirks();
 }

webapp/src/edu/cornell/mannlib/vitro/webapp/modules/tripleSource/TripleStoreQuirks.java

@@ -1,18 +0,0 @@
-/* $This file is distributed under the terms of the license in /doc/license.txt$ */
-
-package edu.cornell.mannlib.vitro.webapp.modules.tripleSource;
-
-import com.hp.hpl.jena.rdf.model.Model;
-
-/**
- * TODO
- */
-public interface TripleStoreQuirks {
-
-	/**
-	 * Test to see whether the FileGraph must be updated to reflect the current
-	 * state of the file.
-	 */
-	boolean hasFileGraphChanged(Model fromFile, Model previous, String graphURI);
-
-}

webapp/src/edu/cornell/mannlib/vitro/webapp/rdfservice/RDFService.java

@@ -159,6 +159,18 @@ public interface RDFService {
 	 */
 	public void serializeGraph(String graphURI, OutputStream outputStream) throws RDFServiceException;
 
+	/**
+	 * Tests to see whether the supplied serialization is equivalent to the 
+	 * named graph, as it exists in the store. Equivalence means that if this 
+	 * serialization were written to the store, the resulting graph would be 
+	 * isomorphic to the existing named graph.
+	 * 
+	 * @param graphURI - the URI of the graph to test against. May not be null.
+	 * @param serializedGraph - the contents to be compared with the existing graph. May not be null.
+	 * @param serializationFormat - May not be null.
+	 */
+	public boolean isEquivalentGraph(String graphURI, InputStream serializedGraph, ModelSerializationFormat serializationFormat);
+	
 	/**
 	 * Registers a listener to listen to changes in any graph in
 	 * the RDF store.

webapp/src/edu/cornell/mannlib/vitro/webapp/rdfservice/filter/LanguageFilteringRDFService.java

@@ -335,6 +335,13 @@ public class LanguageFilteringRDFService implements RDFService {
 		s.serializeGraph(graphURI, outputStream);
 	}
 
+	@Override
+	public boolean isEquivalentGraph(String graphURI,
+			InputStream serializedGraph,
+			ModelSerializationFormat serializationFormat) {
+		return s.isEquivalentGraph(graphURI, serializedGraph, serializationFormat);
+	}
+
 	@Override
     public void registerListener(ChangeListener changeListener)
             throws RDFServiceException {

webapp/src/edu/cornell/mannlib/vitro/webapp/rdfservice/filter/SameAsFilteringRDFServiceFactory.java

@@ -252,6 +252,13 @@ public class SameAsFilteringRDFServiceFactory implements RDFServiceFactory {
     		s.serializeGraph(graphURI, outputStream);
     	}
 
+    	@Override
+    	public boolean isEquivalentGraph(String graphURI,
+    			InputStream serializedGraph,
+    			ModelSerializationFormat serializationFormat) {
+    		return s.isEquivalentGraph(graphURI, serializedGraph, serializationFormat);
+    	}
+
         @Override
         public void close() {
             s.close();

webapp/src/edu/cornell/mannlib/vitro/webapp/rdfservice/impl/RDFServiceFactorySingle.java

@@ -125,6 +125,13 @@ public class RDFServiceFactorySingle implements RDFServiceFactory {
     		s.serializeGraph(graphURI, outputStream);
     	}
 
+    	@Override
+    	public boolean isEquivalentGraph(String graphURI,
+    			InputStream serializedGraph,
+    			ModelSerializationFormat serializationFormat) {
+    		return s.isEquivalentGraph(graphURI, serializedGraph, serializationFormat);
+    	}
+
        @Override
         public void registerListener(ChangeListener changeListener)
                 throws RDFServiceException {

webapp/src/edu/cornell/mannlib/vitro/webapp/rdfservice/impl/jena/RDFServiceJena.java

@@ -39,12 +39,15 @@ import com.hp.hpl.jena.shared.Lock;
 import com.hp.hpl.jena.sparql.core.Quad;
 
 import edu.cornell.mannlib.vitro.webapp.dao.jena.DatasetWrapper;
+import edu.cornell.mannlib.vitro.webapp.dao.jena.RDFServiceDataset;
 import edu.cornell.mannlib.vitro.webapp.dao.jena.SparqlGraph;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.ChangeSet;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.ModelChange;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.RDFService;
+import edu.cornell.mannlib.vitro.webapp.rdfservice.RDFService.ModelSerializationFormat;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.RDFServiceException;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.impl.RDFServiceImpl;
+import edu.cornell.mannlib.vitro.webapp.rdfservice.impl.RDFServiceUtils;
 import edu.cornell.mannlib.vitro.webapp.utils.logging.ToString;
 import edu.cornell.mannlib.vitro.webapp.utils.sparql.ResultSetIterators.ResultSetQuadsIterator;
 import edu.cornell.mannlib.vitro.webapp.utils.sparql.ResultSetIterators.ResultSetTriplesIterator;
@@ -553,6 +556,19 @@ public abstract class RDFServiceJena extends RDFServiceImpl implements RDFServic
 		}
 	}
 
+	/**
+	 * The basic version. Parse the model from the file, read the model from the
+	 * tripleStore, and ask whether they are isomorphic.
+	 */
+	@Override
+	public boolean isEquivalentGraph(String graphURI, InputStream serializedGraph, 
+			ModelSerializationFormat serializationFormat) {
+		Model fileModel = RDFServiceUtils.parseModel(serializedGraph, serializationFormat);
+		Model tripleStoreModel = new RDFServiceDataset(this).getNamedModel(graphURI);
+		Model fromTripleStoreModel = ModelFactory.createDefaultModel().add(tripleStoreModel);
+		return fileModel.isIsomorphicWith(fromTripleStoreModel);
+	}
+
 	@Override
     public void close() {
         // nothing

webapp/src/edu/cornell/mannlib/vitro/webapp/rdfservice/impl/logging/LoggingRDFService.java

@@ -83,6 +83,16 @@ public class LoggingRDFService implements RDFService {
 		}
 	}
 
+	@Override
+	public boolean isEquivalentGraph(String graphURI,
+			InputStream serializedGraph,
+			ModelSerializationFormat serializationFormat) {
+		try (RDFServiceLogger l = new RDFServiceLogger(graphURI)) {
+			return innerService.isEquivalentGraph(graphURI, serializedGraph,
+					serializationFormat);
+		}
+	}
+
 	// ----------------------------------------------------------------------
 	// Untimed methods
 	// ----------------------------------------------------------------------

webapp/src/edu/cornell/mannlib/vitro/webapp/rdfservice/impl/sparql/RDFServiceSparql.java

@@ -46,6 +46,7 @@ import com.hp.hpl.jena.rdf.model.Statement;
 import com.hp.hpl.jena.rdf.model.StmtIterator;
 import com.hp.hpl.jena.sparql.core.Quad;
 
+import edu.cornell.mannlib.vitro.webapp.dao.jena.RDFServiceDataset;
 import edu.cornell.mannlib.vitro.webapp.dao.jena.SparqlGraph;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.ChangeListener;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.ChangeSet;
@@ -54,6 +55,7 @@ import edu.cornell.mannlib.vitro.webapp.rdfservice.RDFService;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.RDFServiceException;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.impl.ChangeSetImpl;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.impl.RDFServiceImpl;
+import edu.cornell.mannlib.vitro.webapp.rdfservice.impl.RDFServiceUtils;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.impl.jena.ListeningGraph;
 import edu.cornell.mannlib.vitro.webapp.utils.sparql.ResultSetIterators.ResultSetQuadsIterator;
 import edu.cornell.mannlib.vitro.webapp.utils.sparql.ResultSetIterators.ResultSetTriplesIterator;
@@ -628,8 +630,6 @@ public class RDFServiceSparql extends RDFServiceImpl implements RDFService {
         Model blankNodeModel = ModelFactory.createDefaultModel();
         blankNodeModel.add(blankNodeStatements);
         
-        
-        
         log.debug("update model size " + model.size());       
         log.debug("blank node model size " + blankNodeModel.size());
         
@@ -843,4 +843,17 @@ public class RDFServiceSparql extends RDFServiceImpl implements RDFService {
 		}
 	}
 
+	/**
+	 * The basic version. Parse the model from the file, read the model from the
+	 * tripleStore, and ask whether they are isomorphic.
+	 */
+	@Override
+	public boolean isEquivalentGraph(String graphURI, InputStream serializedGraph, 
+			ModelSerializationFormat serializationFormat) {
+		Model fileModel = RDFServiceUtils.parseModel(serializedGraph, serializationFormat);
+		Model tripleStoreModel = new RDFServiceDataset(this).getNamedModel(graphURI);
+		Model fromTripleStoreModel = ModelFactory.createDefaultModel().add(tripleStoreModel);
+		return fileModel.isIsomorphicWith(fromTripleStoreModel);
+	}
+
 }

webapp/src/edu/cornell/mannlib/vitro/webapp/servlet/setup/FileGraphSetup.java

@@ -4,9 +4,12 @@ package edu.cornell.mannlib.vitro.webapp.servlet.setup;
 
 import static edu.cornell.mannlib.vitro.webapp.modelaccess.ModelAccess.WhichService.CONTENT;
 
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.io.InputStream;
 import java.nio.file.DirectoryStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -37,6 +40,7 @@ import edu.cornell.mannlib.vitro.webapp.dao.jena.RDFServiceDataset;
 import edu.cornell.mannlib.vitro.webapp.modelaccess.ModelAccess;
 import edu.cornell.mannlib.vitro.webapp.modelaccess.ModelNames;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.RDFService;
+import edu.cornell.mannlib.vitro.webapp.rdfservice.RDFService.ModelSerializationFormat;
 import edu.cornell.mannlib.vitro.webapp.startup.StartupStatus;
 
 // This ContextListener must run after the JenaDataSourceSetup ContextListener
@@ -204,30 +208,26 @@ public class FileGraphSetup implements ServletContextListener {
      */
     public boolean updateGraphInDB(RDFService rdfService, Model fileModel, String type, Path path) {
         String graphURI = pathToURI(path,type);
-        Model dbModel = new RDFServiceDataset(rdfService).getNamedModel(graphURI);
-        boolean modelChanged = false;
-		log.debug(String.format(
-				"%s %s dbModel size is %d, fileModel size is %d", type,
-				path.getFileName(), dbModel.size(), fileModel.size()));
         
+        ByteArrayOutputStream buffer = new ByteArrayOutputStream();
+        fileModel.write(buffer, "N-TRIPLE");
+		InputStream inStream = new ByteArrayInputStream(buffer.toByteArray());
+		if (rdfService.isEquivalentGraph(graphURI, inStream, ModelSerializationFormat.NTRIPLE)) {
+			return false;
+		}
         
-		// Isomorphism has some quirky issues with TDB, and perhaps also with Virtuoso.
+		Model dbModel = new RDFServiceDataset(rdfService).getNamedModel(graphURI);
-		boolean isChanged = ApplicationUtils.instance()
+		if (log.isDebugEnabled()) {
-				.getContentTripleSource().getQuirks()
+			log.debug(String.format(
-				.hasFileGraphChanged(fileModel, dbModel, graphURI);
+					"%s %s dbModel size is %d, fileModel size is %d", type,
+					path.getFileName(), dbModel.size(), fileModel.size()));
+		}
 
-        if (dbModel.isEmpty()  && !fileModel.isEmpty()) {
+		log.info("Updating " + path + " because graphs are not isomorphic");
-            dbModel.add(fileModel);
+		log.info("dbModel: " + dbModel.size() + " ; fileModel: " + fileModel.size());
-            modelChanged = true;
+		dbModel.removeAll();
-        } else if (isChanged) {
+		dbModel.add(fileModel);
-            log.info("Updating " + path + " because graphs are not isomorphic");
+		return true;
-            log.info("dbModel: " + dbModel.size() + " ; fileModel: " + fileModel.size());
-            dbModel.removeAll();
-            dbModel.add(fileModel);
-            modelChanged = true;
-        }
-
-        return modelChanged;
     }
 
     /*

webapp/src/edu/cornell/mannlib/vitro/webapp/triplesource/impl/DefaultTripleStoreQuirks.java

@@ -1,27 +0,0 @@
-/* $This file is distributed under the terms of the license in /doc/license.txt$ */
-
-package edu.cornell.mannlib.vitro.webapp.triplesource.impl;
-
-import com.hp.hpl.jena.rdf.model.Model;
-import com.hp.hpl.jena.rdf.model.ModelFactory;
-
-import edu.cornell.mannlib.vitro.webapp.modules.tripleSource.TripleStoreQuirks;
-
-/**
- * The behavior for non-quirky TripleSource implementations.
- */
-public class DefaultTripleStoreQuirks implements TripleStoreQuirks {
-
-	@Override
-	public boolean hasFileGraphChanged(Model fromFile, Model previous,
-			String graphURI) {
-		/**
-		 * The test for isomorphism involves a large number of ASK queries. It
-		 * appears to be faster to read the previous graph data into memory than
-		 * to run those queries against the RDFService.
-		 */
-		return !fromFile.isIsomorphicWith(ModelFactory.createDefaultModel()
-				.add(previous));
-	}
-
-}

webapp/src/edu/cornell/mannlib/vitro/webapp/triplesource/impl/sdb/ContentTripleSourceSDB.java

@@ -38,13 +38,11 @@ import edu.cornell.mannlib.vitro.webapp.modelaccess.ontmodels.UnionModelsOntMode
 import edu.cornell.mannlib.vitro.webapp.modules.Application;
 import edu.cornell.mannlib.vitro.webapp.modules.ComponentStartupStatus;
 import edu.cornell.mannlib.vitro.webapp.modules.tripleSource.ContentTripleSource;
-import edu.cornell.mannlib.vitro.webapp.modules.tripleSource.TripleStoreQuirks;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.RDFService;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.RDFServiceFactory;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.impl.jena.sdb.RDFServiceFactorySDB;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.impl.logging.LoggingRDFServiceFactory;
 import edu.cornell.mannlib.vitro.webapp.servlet.setup.JenaDataSourceSetupBase;
-import edu.cornell.mannlib.vitro.webapp.triplesource.impl.DefaultTripleStoreQuirks;
 import edu.cornell.mannlib.vitro.webapp.utils.logging.ToString;
 
 /**
@@ -79,8 +77,6 @@ public class ContentTripleSourceSDB extends ContentTripleSource {
 	static final boolean DEFAULT_TESTONBORROW = true;
 	static final boolean DEFAULT_TESTONRETURN = true;
 	
-	private final TripleStoreQuirks quirks = new DefaultTripleStoreQuirks();
-
 	private ServletContext ctx;
 	private ComboPooledDataSource ds;
 	private RDFServiceFactory rdfServiceFactory;
@@ -209,11 +205,6 @@ public class ContentTripleSourceSDB extends ContentTripleSource {
 		return new UnionModelsOntModelsCache(combinedCache, CONTENT_UNIONS);
 	}
 
-	@Override
-	public TripleStoreQuirks getQuirks() {
-		return quirks;
-	}
-
 	@Override
 	public String toString() {
 		return "ContentTripleSourceSDB[" + ToString.hashHex(this) + "]";

webapp/src/edu/cornell/mannlib/vitro/webapp/triplesource/impl/sparql/ContentTripleSourceSPARQL.java

@@ -13,13 +13,11 @@ import edu.cornell.mannlib.vitro.webapp.modelaccess.ontmodels.OntModelCache;
 import edu.cornell.mannlib.vitro.webapp.modules.Application;
 import edu.cornell.mannlib.vitro.webapp.modules.ComponentStartupStatus;
 import edu.cornell.mannlib.vitro.webapp.modules.tripleSource.ContentTripleSource;
-import edu.cornell.mannlib.vitro.webapp.modules.tripleSource.TripleStoreQuirks;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.RDFService;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.RDFServiceFactory;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.impl.RDFServiceFactorySingle;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.impl.logging.LoggingRDFServiceFactory;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.impl.sparql.RDFServiceSparql;
-import edu.cornell.mannlib.vitro.webapp.triplesource.impl.DefaultTripleStoreQuirks;
 import edu.cornell.mannlib.vitro.webapp.utils.configuration.Property;
 import edu.cornell.mannlib.vitro.webapp.utils.configuration.Validation;
 import edu.cornell.mannlib.vitro.webapp.utils.logging.ToString;
@@ -38,8 +36,6 @@ public class ContentTripleSourceSPARQL extends ContentTripleSource {
 	private String endpointURI;
 	private String updateEndpointURI; // Optional
 	
-	private final TripleStoreQuirks quirks = new DefaultTripleStoreQuirks();
-
 	private RDFService rdfService;
 	private RDFServiceFactory rdfServiceFactory;
 	private Dataset dataset;
@@ -136,11 +132,6 @@ public class ContentTripleSourceSPARQL extends ContentTripleSource {
 		return longTermOntModelCache;
 	}
 
-	@Override
-	public TripleStoreQuirks getQuirks() {
-		return quirks;
-	}
-
 	@Override
 	public String toString() {
 		return "ContentTripleSourceSPARQL[" + ToString.hashHex(this)

webapp/src/edu/cornell/mannlib/vitro/webapp/triplesource/impl/tdb/ConfigurationTripleSourceTDB.java

@@ -18,7 +18,6 @@ import edu.cornell.mannlib.vitro.webapp.modelaccess.ontmodels.OntModelCache;
 import edu.cornell.mannlib.vitro.webapp.modules.Application;
 import edu.cornell.mannlib.vitro.webapp.modules.ComponentStartupStatus;
 import edu.cornell.mannlib.vitro.webapp.modules.tripleSource.ConfigurationTripleSource;
-import edu.cornell.mannlib.vitro.webapp.modules.tripleSource.TripleStoreQuirks;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.RDFService;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.RDFServiceFactory;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.impl.RDFServiceFactorySingle;
@@ -42,8 +41,6 @@ import edu.cornell.mannlib.vitro.webapp.utils.logging.ToString;
 public class ConfigurationTripleSourceTDB extends ConfigurationTripleSource {
 	private static final String DIRECTORY_TDB = "tdbModels";
 
-	private final TripleStoreQuirks quirks = new TDBTripleStoreQuirks();
-
 	private volatile RDFService rdfService;
 	private RDFServiceFactory rdfServiceFactory;
 	private RDFService unclosableRdfService;
@@ -114,11 +111,6 @@ public class ConfigurationTripleSourceTDB extends ConfigurationTripleSource {
 		return longTermOntModelCache;
 	}
 
-	@Override
-	public TripleStoreQuirks getQuirks() {
-		return quirks;
-	}
-
 	@Override
 	public String toString() {
 		return "ConfigurationTripleSourceTDB[" + ToString.hashHex(this) + "]";

webapp/src/edu/cornell/mannlib/vitro/webapp/triplesource/impl/tdb/ContentTripleSourceTDB.java

@@ -16,7 +16,6 @@ import edu.cornell.mannlib.vitro.webapp.modelaccess.ontmodels.OntModelCache;
 import edu.cornell.mannlib.vitro.webapp.modules.Application;
 import edu.cornell.mannlib.vitro.webapp.modules.ComponentStartupStatus;
 import edu.cornell.mannlib.vitro.webapp.modules.tripleSource.ContentTripleSource;
-import edu.cornell.mannlib.vitro.webapp.modules.tripleSource.TripleStoreQuirks;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.RDFService;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.RDFServiceFactory;
 import edu.cornell.mannlib.vitro.webapp.rdfservice.impl.RDFServiceFactorySingle;
@@ -40,8 +39,6 @@ import edu.cornell.mannlib.vitro.webapp.utils.logging.ToString;
  * Memory-map the small content models, and add the standard decorators.
  */
 public class ContentTripleSourceTDB extends ContentTripleSource {
-	private final TripleStoreQuirks quirks = new TDBTripleStoreQuirks();
-
 	private String tdbPath;
 
 	private volatile RDFService rdfService;
@@ -127,11 +124,6 @@ public class ContentTripleSourceTDB extends ContentTripleSource {
 		return longTermOntModelCache;
 	}
 
-	@Override
-	public TripleStoreQuirks getQuirks() {
-		return quirks;
-	}
-
 	@Override
 	public String toString() {
 		return "ContentTripleSourceTDB[" + ToString.hashHex(this) + "]";

webapp/src/edu/cornell/mannlib/vitro/webapp/triplesource/impl/tdb/TDBTripleStoreQuirks.java

@@ -1,71 +0,0 @@
-/* $This file is distributed under the terms of the license in /doc/license.txt$ */
-
-package edu.cornell.mannlib.vitro.webapp.triplesource.impl.tdb;
-
-import static com.hp.hpl.jena.datatypes.xsd.XSDDatatype.XSDinteger;
-import static com.hp.hpl.jena.datatypes.xsd.XSDDatatype.XSDnonNegativeInteger;
-
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
-import java.io.InputStream;
-
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
-
-import com.hp.hpl.jena.rdf.model.Model;
-import com.hp.hpl.jena.rdf.model.ModelFactory;
-
-import edu.cornell.mannlib.vitro.webapp.triplesource.impl.DefaultTripleStoreQuirks;
-
-/**
- * TDB has some odd behaviors to deal with.
- */
-public class TDBTripleStoreQuirks extends DefaultTripleStoreQuirks {
-	private static final Log log = LogFactory
-			.getLog(TDBTripleStoreQuirks.class);
-
-	/**
-	 * When the file graph was previously written to the TDB store, TDB mangled
-	 * some of the literal types: any type of XMLSchema#nonNegativeInteger was
-	 * changed to XMLSchema#integer.
-	 * 
-	 * We need to mangle our new model in the same way before comparing to the
-	 * previous one.
-	 */
-	@Override
-	public boolean hasFileGraphChanged(Model fromFile, Model previous,
-			String graphURI) {
-		try {
-			ByteArrayOutputStream buffer = new ByteArrayOutputStream();
-			fromFile.write(buffer, "N-TRIPLE");
-			String fromString = buffer.toString("UTF-8");
-
-			String mangleString = fromString.replace(
-					XSDnonNegativeInteger.getURI(), XSDinteger.getURI());
-			InputStream mangleStream = new ByteArrayInputStream(
-					mangleString.getBytes("UTF-8"));
-			Model mangled = ModelFactory.createDefaultModel();
-			mangled.read(mangleStream, null, "N-TRIPLE");
-
-			return !isIsomorphic(previous, mangled);
-		} catch (Exception e) {
-			log.warn("Failed to test for changes in filegraph. "
-					+ "Change assumed.", e);
-			return true;
-		}
-	}
-
-	/**
-	 * If we check isomorphism with a dbModel directly, we issue many ASK
-	 * queries against the underlying RDFService.
-	 * 
-	 * It's faster to read the entire model from the RDFService and then issue
-	 * all of those ASKs against a memory-resident model.
-	 */
-	private boolean isIsomorphic(Model previous, Model mangled) {
-		Model previousInMemory = ModelFactory.createDefaultModel()
-				.add(previous);
-		return mangled.isIsomorphicWith(previousInMemory);
-	}
-
-}