fix RDF preview

fadmaa · Nov 25, 2014 · a6d8367 · a6d8367
1 parent d66b996
commit a6d8367
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Showing 2 changed files with 52 additions and 54 deletions.
diff --git a/src/org/deri/grefine/rdf/commands/PreviewRdfCommand.java b/src/org/deri/grefine/rdf/commands/PreviewRdfCommand.java
@@ -1,32 +1,28 @@
 package org.deri.grefine.rdf.commands;
 
-import java.io.IOException;
-import java.io.StringWriter;
-
-import javax.servlet.ServletException;
-import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpServletResponse;
-
+import com.google.refine.browsing.Engine;
+import com.google.refine.commands.Command;
+import com.google.refine.model.Project;
+import com.google.refine.model.Row;
+import com.google.refine.util.ParsingUtilities;
 import org.deri.grefine.rdf.Node;
 import org.deri.grefine.rdf.RdfSchema;
 import org.deri.grefine.rdf.exporters.RdfExporter;
 import org.deri.grefine.rdf.exporters.RdfExporter.RdfRowVisitor;
 import org.deri.grefine.rdf.vocab.Vocabulary;
 import org.json.JSONObject;
 import org.json.JSONWriter;
-import org.openrdf.repository.Repository;
-import org.openrdf.repository.RepositoryConnection;
 import org.openrdf.repository.RepositoryException;
 import org.openrdf.rio.RDFFormat;
 import org.openrdf.rio.RDFHandlerException;
 import org.openrdf.rio.RDFWriter;
 import org.openrdf.rio.Rio;
 
-import com.google.refine.browsing.Engine;
-import com.google.refine.commands.Command;
-import com.google.refine.model.Project;
-import com.google.refine.model.Row;
-import com.google.refine.util.ParsingUtilities;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.io.StringWriter;
 
 public class PreviewRdfCommand extends Command {
 
@@ -43,8 +39,10 @@ public void doPost(HttpServletRequest request, HttpServletResponse response)
             String jsonString = request.getParameter("schema");
             JSONObject json = ParsingUtilities.evaluateJsonStringToObject(jsonString);
             final RdfSchema schema = RdfSchema.reconstruct(json);
-
-            RdfRowVisitor visitor = new RdfRowVisitor(schema) {
+
+	        StringWriter sw = new StringWriter();
+	        RDFWriter w = Rio.createWriter(RDFFormat.TURTLE, sw);
+	        RdfRowVisitor visitor = new RdfRowVisitor(schema, w) {
             	final int limit = 10;
             	int _count;
 				@Override
@@ -56,29 +54,26 @@ public boolean visit(Project project, int rowIndex, Row row) {
 						root.createNode(baseUri, factory, con, project, row, rowIndex,blanks);
 					}
 		            _count +=1;
+
+					try {
+						flushStatements();
+					} catch (RepositoryException e) {
+						e.printStackTrace();
+						return true;
+					} catch (RDFHandlerException e) {
+						e.printStackTrace();
+						return true;
+					}
+
 		            return false;
 				}
 			};
 
-            Repository model = RdfExporter.buildModel(project, engine, visitor);
-            StringWriter sw = new StringWriter();
-            try{
-            	RepositoryConnection con = model.getConnection();
-            	try{
-            		RDFWriter w = Rio.createWriter(RDFFormat.TURTLE, sw);
-            		for(Vocabulary v:schema.getPrefixesMap().values()){
-            			w.handleNamespace(v.getName(), v.getUri());
-            		}
-            		con.export(w);
-    			}finally{
-            		con.close();
-            	}
-            }catch(RepositoryException ex){
-            	throw new RuntimeException(ex);
-            }catch(RDFHandlerException ex){
-            	throw new RuntimeException(ex);
-            }
-
+	        for(Vocabulary v:schema.getPrefixesMap().values()){
+		        w.handleNamespace(v.getName(), v.getUri());
+	        }
+	        RdfExporter.buildModel(project, engine, visitor);
+
             JSONWriter writer = new JSONWriter(response.getWriter());
             writer.object();
             writer.key("v");

diff --git a/src/org/deri/grefine/rdf/exporters/RdfExporter.java b/src/org/deri/grefine/rdf/exporters/RdfExporter.java
@@ -88,30 +88,13 @@ public boolean visit(Project project, int rowIndex, Row row) {
 				for(Node root:roots){
 					root.createNode(baseUri, factory, con, project, row, rowIndex,blanks);
 				}
-				try {
-					List<Resource> resourceList = con.getContextIDs().asList();
-					Resource[] resources = resourceList.toArray(new Resource[resourceList.size()]);
-
-					// Export statements
-					CloseableIteration<? extends Statement, RepositoryException> stIter =
-							con.getStatements(null, null, null, false, resources);
-
-					try {
-						while (stIter.hasNext()) {
-							this.writer.handleStatement(stIter.next());
-						}
-					} finally {
-						stIter.close();
-					}
 
-					// empty the repository
-					con.clear();
+				try {
+					flushStatements();
 				} catch (RepositoryException e) {
 					e.printStackTrace();
-					return true;
 				} catch (RDFHandlerException e) {
 					e.printStackTrace();
-					return true;
 				}
 
 				return false;
@@ -218,6 +201,26 @@ public void start(Project project) {
 	        }
         }
 
+	    protected void flushStatements() throws RepositoryException, RDFHandlerException{
+		    List<Resource> resourceList = con.getContextIDs().asList();
+		    Resource[] resources = resourceList.toArray(new Resource[resourceList.size()]);
+
+		    // Export statements
+		    CloseableIteration<? extends Statement, RepositoryException> stIter =
+				    con.getStatements(null, null, null, false, resources);
+
+		    try {
+			    while (stIter.hasNext()) {
+				    this.writer.handleStatement(stIter.next());
+			    }
+		    } finally {
+			    stIter.close();
+		    }
+
+		    // empty the repository
+		    con.clear();
+	    }
+
         abstract public boolean visit(Project project, int rowIndex, Row row);
         public RdfSchema getRdfSchema(){
         	return schema;