Merge pull request #6 from LinkedDataFragments/master

merging in latest changes from origin

src/org/linkeddatafragments/datasource/AbstractRequestProcessor.java

@@ -1,7 +1,7 @@
 package org.linkeddatafragments.datasource;
 
-import org.linkeddatafragments.fragments.LinkedDataFragment;
-import org.linkeddatafragments.fragments.LinkedDataFragmentRequest;
+import org.linkeddatafragments.fragments.ILinkedDataFragment;
+import org.linkeddatafragments.fragments.ILinkedDataFragmentRequest;
 
 /**
  * Base class for implementations of {@link IFragmentRequestProcessor}.
@@ -15,28 +15,28 @@ abstract public class AbstractRequestProcessor
     public void close() {}
 
     @Override
-    final public LinkedDataFragment createRequestedFragment(
-            final LinkedDataFragmentRequest request )
+    final public ILinkedDataFragment createRequestedFragment(
+            final ILinkedDataFragmentRequest request )
                     throws IllegalArgumentException
     {
         return getWorker( request ).createRequestedFragment();
     }
 
     abstract protected Worker getWorker(
-            final LinkedDataFragmentRequest request )
+            final ILinkedDataFragmentRequest request )
                     throws IllegalArgumentException;
 
 
     abstract static protected class Worker
     {
-        public final LinkedDataFragmentRequest request;
+        public final ILinkedDataFragmentRequest request;
 
-        public Worker( final LinkedDataFragmentRequest request )
+        public Worker( final ILinkedDataFragmentRequest request )
         {
             this.request = request;
         }
 
-        abstract public LinkedDataFragment createRequestedFragment()
+        abstract public ILinkedDataFragment createRequestedFragment()
                                                throws IllegalArgumentException;
 
     } // end of class Worker

src/org/linkeddatafragments/datasource/AbstractRequestProcessorForTriplePatterns.java

@@ -2,91 +2,97 @@
 
 import com.hp.hpl.jena.rdf.model.Model;
 
-import org.linkeddatafragments.fragments.LinkedDataFragment;
-import org.linkeddatafragments.fragments.LinkedDataFragmentRequest;
-import org.linkeddatafragments.fragments.tpf.TriplePatternElement;
-import org.linkeddatafragments.fragments.tpf.TriplePatternFragment;
+import org.linkeddatafragments.fragments.ILinkedDataFragment;
+import org.linkeddatafragments.fragments.ILinkedDataFragmentRequest;
+import org.linkeddatafragments.fragments.tpf.ITriplePatternElement;
+import org.linkeddatafragments.fragments.tpf.ITriplePatternFragment;
 import org.linkeddatafragments.fragments.tpf.TriplePatternFragmentImpl;
-import org.linkeddatafragments.fragments.tpf.TriplePatternFragmentRequest;
+import org.linkeddatafragments.fragments.tpf.ITriplePatternFragmentRequest;
 
 /**
  * Base class for implementations of {@link IFragmentRequestProcessor} that
- * process {@link TriplePatternFragmentRequest}s.
+ * process {@link ITriplePatternFragmentRequest}s.
  *
- * @param <TermType> type for representing RDF terms in triple patterns 
- * @param <VarType> type for representing specific variables in triple patterns
+ * @param <CTT>
+ *          type for representing constants in triple patterns (i.e., URIs and
+ *          literals)
+ * @param <NVT>
+ *          type for representing named variables in triple patterns
+ * @param <AVT>
+ *          type for representing anonymous variables in triple patterns (i.e.,
+ *          variables denoted by a blank node)
  *
  * @author <a href="http://olafhartig.de">Olaf Hartig</a>
  */
 public abstract class
-    AbstractRequestProcessorForTriplePatterns<TermType,VarType>
+    AbstractRequestProcessorForTriplePatterns<CTT,NVT,AVT>
         extends AbstractRequestProcessor
 {
     @Override
-    protected final Worker<TermType,VarType> getWorker(
-            final LinkedDataFragmentRequest request )
+    protected final Worker<CTT,NVT,AVT> getWorker(
+            final ILinkedDataFragmentRequest request )
                                                 throws IllegalArgumentException
     {
-        if ( request instanceof TriplePatternFragmentRequest<?,?> ) {
+        if ( request instanceof ITriplePatternFragmentRequest<?,?,?> ) {
             @SuppressWarnings("unchecked")
-            final TriplePatternFragmentRequest<TermType,VarType> tpfRequest =
-                      (TriplePatternFragmentRequest<TermType,VarType>) request;
+            final ITriplePatternFragmentRequest<CTT,NVT,AVT> tpfRequest =
+                      (ITriplePatternFragmentRequest<CTT,NVT,AVT>) request;
             return getTPFSpecificWorker( tpfRequest );
         }
         else
             throw new IllegalArgumentException( request.getClass().getName() );
     }
 
-    abstract protected Worker<TermType,VarType> getTPFSpecificWorker(
-            final TriplePatternFragmentRequest<TermType,VarType> request )
+    abstract protected Worker<CTT,NVT,AVT> getTPFSpecificWorker(
+            final ITriplePatternFragmentRequest<CTT,NVT,AVT> request )
                     throws IllegalArgumentException;
 
 
-    abstract static protected class Worker<TermType,VarType>
+    abstract static protected class Worker<CTT,NVT,AVT>
         extends AbstractRequestProcessor.Worker
     {        
         public Worker(
-                 final TriplePatternFragmentRequest<TermType,VarType> request )
+                 final ITriplePatternFragmentRequest<CTT,NVT,AVT> request )
         {
             super( request );
         }
 
         @Override
-        public LinkedDataFragment createRequestedFragment()
+        public ILinkedDataFragment createRequestedFragment()
                                                 throws IllegalArgumentException
         {
-            final long limit = LinkedDataFragmentRequest.TRIPLESPERPAGE;
+            final long limit = ILinkedDataFragmentRequest.TRIPLESPERPAGE;
             final long offset;
             if ( request.isPageRequest() )
                 offset = limit * ( request.getPageNumber() - 1L );
             else
                 offset = 0L;
 
             @SuppressWarnings("unchecked")
-            final TriplePatternFragmentRequest<TermType,VarType> tpfRequest =
-                      (TriplePatternFragmentRequest<TermType,VarType>) request;
+            final ITriplePatternFragmentRequest<CTT,NVT,AVT> tpfRequest =
+                      (ITriplePatternFragmentRequest<CTT,NVT,AVT>) request;
 
             return createFragment( tpfRequest.getSubject(),
                                    tpfRequest.getPredicate(),
                                    tpfRequest.getObject(),
                                    offset, limit );
         }
 
-        abstract protected LinkedDataFragment createFragment(
-                            final TriplePatternElement<TermType,VarType> subj,
-                            final TriplePatternElement<TermType,VarType> pred,
-                            final TriplePatternElement<TermType,VarType> obj,
+        abstract protected ILinkedDataFragment createFragment(
+                            final ITriplePatternElement<CTT,NVT,AVT> subj,
+                            final ITriplePatternElement<CTT,NVT,AVT> pred,
+                            final ITriplePatternElement<CTT,NVT,AVT> obj,
                             final long offset,
                             final long limit )
                                                throws IllegalArgumentException;
 
-        protected TriplePatternFragment createEmptyTriplePatternFragment()
+        protected ITriplePatternFragment createEmptyTriplePatternFragment()
         {
             return new TriplePatternFragmentImpl( request.getFragmentURL(),
                                                   request.getDatasetURL() );
         }
 
-        protected TriplePatternFragment createTriplePatternFragment(
+        protected ITriplePatternFragment createTriplePatternFragment(
                                                      final Model triples,
                                                      final long totalSize,
                                                      final boolean isLastPage )

src/org/linkeddatafragments/datasource/DataSource.java → src/org/linkeddatafragments/datasource/DataSourceBase.java

@@ -5,11 +5,11 @@
  * @author mielvandersande
  * @author Bart Hanssens
  */
-public abstract class DataSource implements IDataSource {
+public abstract class DataSourceBase implements IDataSource {
     protected String title;
     protected String description; 
 
-    public DataSource(String title, String description) {
+    public DataSourceBase(String title, String description) {
         this.title = title;
         this.description = description;
     }

src/org/linkeddatafragments/datasource/DataSourceFactory.java

@@ -1,7 +1,7 @@
 package org.linkeddatafragments.datasource;
 
 import com.google.gson.JsonObject;
-import org.linkeddatafragments.exceptions.DataSourceException;
+import org.linkeddatafragments.exceptions.DataSourceCreationException;
 import org.linkeddatafragments.exceptions.UnknownDataSourceTypeException;
 
 /**
@@ -16,9 +16,9 @@ public class DataSourceFactory {
      * 
      * @param config
      * @return datasource interface
-     * @throws DataSourceException 
+     * @throws DataSourceCreationException 
      */
-    public static IDataSource create(JsonObject config) throws DataSourceException {
+    public static IDataSource create(JsonObject config) throws DataSourceCreationException {
         String title = config.getAsJsonPrimitive("title").getAsString();
         String description = config.getAsJsonPrimitive("description").getAsString();
         String typeName = config.getAsJsonPrimitive("type").getAsString();

src/org/linkeddatafragments/datasource/IDataSourceType.java

@@ -1,6 +1,6 @@
 package org.linkeddatafragments.datasource;
 
-import org.linkeddatafragments.exceptions.DataSourceException;
+import org.linkeddatafragments.exceptions.DataSourceCreationException;
 
 import com.google.gson.JsonObject;
 
@@ -28,5 +28,5 @@ public interface IDataSourceType
     IDataSource createDataSource( final String title,
                                   final String description,
                                   final JsonObject settings )
-                                                    throws DataSourceException;
+                                                    throws DataSourceCreationException;
 }

src/org/linkeddatafragments/datasource/IFragmentRequestProcessor.java

@@ -2,18 +2,20 @@
 
 import java.io.Closeable;
 
-import org.linkeddatafragments.fragments.LinkedDataFragment;
-import org.linkeddatafragments.fragments.LinkedDataFragmentRequest;
+import org.linkeddatafragments.fragments.ILinkedDataFragment;
+import org.linkeddatafragments.fragments.ILinkedDataFragment;
+import org.linkeddatafragments.fragments.ILinkedDataFragmentRequest;
+import org.linkeddatafragments.fragments.ILinkedDataFragmentRequest;
 
 /**
- * Processes {@link LinkedDataFragmentRequest}s and returns
- * the requested {@link LinkedDataFragment}s.
+ * Processes {@link ILinkedDataFragmentRequest}s and returns
+ * the requested {@link ILinkedDataFragment}s.
  *
  * @author <a href="http://olafhartig.de">Olaf Hartig</a>
  */
 public interface IFragmentRequestProcessor extends Closeable
 {
-    LinkedDataFragment createRequestedFragment(
-            final LinkedDataFragmentRequest request )
+    ILinkedDataFragment createRequestedFragment(
+            final ILinkedDataFragmentRequest request )
                     throws IllegalArgumentException;
 }

src/org/linkeddatafragments/datasource/hdt/HdtBasedRequestProcessorForTPFs.java

@@ -4,9 +4,9 @@
 
 import org.linkeddatafragments.datasource.AbstractRequestProcessorForTriplePatterns;
 import org.linkeddatafragments.datasource.IFragmentRequestProcessor;
-import org.linkeddatafragments.fragments.LinkedDataFragment;
-import org.linkeddatafragments.fragments.tpf.TriplePatternElement;
-import org.linkeddatafragments.fragments.tpf.TriplePatternFragmentRequest;
+import org.linkeddatafragments.fragments.ILinkedDataFragment;
+import org.linkeddatafragments.fragments.tpf.ITriplePatternElement;
+import org.linkeddatafragments.fragments.tpf.ITriplePatternFragmentRequest;
 import org.rdfhdt.hdt.enums.TripleComponentRole;
 import org.rdfhdt.hdt.hdt.HDT;
 import org.rdfhdt.hdt.hdt.HDTManager;
@@ -21,13 +21,13 @@
 
 /**
  * Implementation of {@link IFragmentRequestProcessor} that processes
- * {@link TriplePatternFragmentRequest}s over data stored in HDT.
+ * {@link ITriplePatternFragmentRequest}s over data stored in HDT.
  *
  * @author Ruben Verborgh
  * @author <a href="http://olafhartig.de">Olaf Hartig</a>
  */
 public class HdtBasedRequestProcessorForTPFs
-    extends AbstractRequestProcessorForTriplePatterns<RDFNode,String>
+    extends AbstractRequestProcessorForTriplePatterns<RDFNode,String,String>
 {
     protected final HDT datasource;
     protected final NodeDictionary dictionary;
@@ -46,38 +46,40 @@ public HdtBasedRequestProcessorForTPFs( String hdtFile ) throws IOException
 
     @Override
     protected Worker getTPFSpecificWorker(
-            final TriplePatternFragmentRequest<RDFNode,String> request )
+            final ITriplePatternFragmentRequest<RDFNode,String,String> request )
                                                 throws IllegalArgumentException
     {
         return new Worker( request );
     }
 
 
     protected class Worker
-       extends AbstractRequestProcessorForTriplePatterns.Worker<RDFNode,String>
+       extends AbstractRequestProcessorForTriplePatterns.Worker<RDFNode,String,String>
     {
-        public Worker( final TriplePatternFragmentRequest<RDFNode,String> req )
+        public Worker(
+                final ITriplePatternFragmentRequest<RDFNode,String,String> req )
         {
             super( req );
         }
 
         @Override
-        protected LinkedDataFragment createFragment(
-                          final TriplePatternElement<RDFNode,String> subject,
-                          final TriplePatternElement<RDFNode,String> predicate,
-                          final TriplePatternElement<RDFNode,String> object,
-                          final long offset,
-                          final long limit )
+        protected ILinkedDataFragment createFragment(
+                   final ITriplePatternElement<RDFNode,String,String> subject,
+                   final ITriplePatternElement<RDFNode,String,String> predicate,
+                   final ITriplePatternElement<RDFNode,String,String> object,
+                   final long offset,
+                   final long limit )
         {
             // FIXME: The following algorithm is incorrect for cases in which
             //        the requested triple pattern contains a specific variable
-            //        multiple times (e.g., ?x foaf:knows ?x ).
+            //        multiple times;
+            //        e.g., (?x foaf:knows ?x ) or (_:bn foaf:knows _:bn)
             // see https://github.com/LinkedDataFragments/Server.Java/issues/23
 
             // look up the result from the HDT datasource)
-            int subjectId = subject.isVariable() ? 0 : dictionary.getIntID(subject.asTerm().asNode(), TripleComponentRole.SUBJECT);
-            int predicateId = predicate.isVariable() ? 0 : dictionary.getIntID(predicate.asTerm().asNode(), TripleComponentRole.PREDICATE);
-            int objectId = object.isVariable() ? 0 : dictionary.getIntID(object.asTerm().asNode(), TripleComponentRole.OBJECT);
+            int subjectId = subject.isVariable() ? 0 : dictionary.getIntID(subject.asConstantTerm().asNode(), TripleComponentRole.SUBJECT);
+            int predicateId = predicate.isVariable() ? 0 : dictionary.getIntID(predicate.asConstantTerm().asNode(), TripleComponentRole.PREDICATE);
+            int objectId = object.isVariable() ? 0 : dictionary.getIntID(object.asConstantTerm().asNode(), TripleComponentRole.OBJECT);
 
             if (subjectId < 0 || predicateId < 0 || objectId < 0) {
                 return createEmptyTriplePatternFragment();

src/org/linkeddatafragments/datasource/hdt/HdtDataSource.java

@@ -2,7 +2,7 @@
 
 import java.io.IOException;
 
-import org.linkeddatafragments.datasource.DataSource;
+import org.linkeddatafragments.datasource.DataSourceBase;
 import org.linkeddatafragments.datasource.IFragmentRequestProcessor;
 import org.linkeddatafragments.fragments.IFragmentRequestParser;
 import org.linkeddatafragments.fragments.tpf.TPFRequestParserForJenaBackends;
@@ -13,7 +13,7 @@
  * @author Ruben Verborgh
  * @author <a href="http://olafhartig.de">Olaf Hartig</a>
  */
-public class HdtDataSource extends DataSource {
+public class HdtDataSource extends DataSourceBase {
 
     protected final HdtBasedRequestProcessorForTPFs requestProcessor;
 

src/org/linkeddatafragments/datasource/hdt/HdtDataSourceType.java

@@ -5,7 +5,7 @@
 
 import org.linkeddatafragments.datasource.IDataSource;
 import org.linkeddatafragments.datasource.IDataSourceType;
-import org.linkeddatafragments.exceptions.DataSourceException;
+import org.linkeddatafragments.exceptions.DataSourceCreationException;
 
 import com.google.gson.JsonObject;
 
@@ -20,15 +20,15 @@ public class HdtDataSourceType implements IDataSourceType
     public IDataSource createDataSource( final String title,
                                          final String description,
                                          final JsonObject settings )
-                                                     throws DataSourceException
+                                                     throws DataSourceCreationException
     {
         final String fname = settings.getAsJsonPrimitive("file").getAsString();
         final File file = new File( fname );
 
         try {
             return new HdtDataSource(title, description, file.getAbsolutePath());
         } catch (IOException ex) {
-            throw new DataSourceException(ex);
+            throw new DataSourceCreationException(ex);
         }
     }
 

src/org/linkeddatafragments/datasource/index/IndexDataSource.java

@@ -2,7 +2,7 @@
 
 import java.util.HashMap;
 
-import org.linkeddatafragments.datasource.DataSource;
+import org.linkeddatafragments.datasource.DataSourceBase;
 import org.linkeddatafragments.datasource.IDataSource;
 import org.linkeddatafragments.datasource.IFragmentRequestProcessor;
 import org.linkeddatafragments.fragments.IFragmentRequestParser;
@@ -14,7 +14,7 @@
  * @author Miel Vander Sande
  * @author <a href="http://olafhartig.de">Olaf Hartig</a>
  */
-public class IndexDataSource extends DataSource {
+public class IndexDataSource extends DataSourceBase {
 
     protected final IndexRequestProcessorForTPFs requestProcessor;