Uses all possible identifiers to generate URIs.

This commit enables dspace-rdf to use all PersistentIdentifiers minted
by DSpace and not only handles. It makes advantage of the changes
introduced to DSpace by DS-1990. Persistent Identifers should and will
be used as fully functional http URIs only (e.g. a DOI will be used in
the form http://dx.doi.org/<doi> and not as doi:<doi>).

dspace-rdf/src/main/java/org/dspace/rdf/RDFConsumer.java

@@ -111,7 +111,7 @@ public class RDFConsumer implements Consumer
                 Item[] items = b.getItems();
                 for (Item i : items)
                 {
-                    DSOIdentifier id = new DSOIdentifier(i);
+                    DSOIdentifier id = new DSOIdentifier(i, ctx);
                     if (!this.toDelete.contains(id) && !this.toConvert.contains(id))
                     {
                         this.toConvert.addLast(id);
@@ -156,7 +156,7 @@ public class RDFConsumer implements Consumer
             Item[] items = bundle.getItems();
             for (Item i : items)
             {
-                DSOIdentifier id = new DSOIdentifier(i);
+                DSOIdentifier id = new DSOIdentifier(i, ctx);
                 if (!this.toDelete.contains(id) && !this.toConvert.contains(id))
                 {
                     this.toConvert.addLast(id);
@@ -191,7 +191,7 @@ public class RDFConsumer implements Consumer
         if (event.getEventType() == Event.DELETE)
         {
             DSOIdentifier id = new DSOIdentifier(event.getSubjectType(), 
-                    event.getSubjectID(), event.getDetail());
+                    event.getSubjectID(), event.getDetail(), event.getIdentifiers());
             
             if (this.toConvert.contains(id))
             {
@@ -222,7 +222,7 @@ public class RDFConsumer implements Consumer
                         + "event with the type REMOVE.");
                 return;
             }
-            DSOIdentifier id = new DSOIdentifier(dso);
+            DSOIdentifier id = new DSOIdentifier(dso, ctx);
 
             // If an item gets withdrawn, a MODIFIY event is fired. We have to
             // delete the item from the triple store instead of converting it.
@@ -260,7 +260,7 @@ public class RDFConsumer implements Consumer
                 || event.getEventType() == Event.REMOVE)
         {
             DSOIdentifier id = new DSOIdentifier(Constants.SITE,
-                    Site.SITE_ID, Site.getSiteHandle());
+                    Site.SITE_ID, Site.getSiteHandle(), new String[] {Site.getSiteHandle()});
             if (!this.toConvert.contains(id)) this.toConvert.add(id);
             return;
         }
@@ -393,12 +393,12 @@ public class RDFConsumer implements Consumer
             throws SQLException {
         try
         {
-            RDFUtil.delete(context, id.type, id.id, id.handle);
+            RDFUtil.delete(context, id.type, id.id, id.handle, id.identifiers);
         }
         catch (RDFMissingIdentifierException ex)
         {
             log.warn("Cannot delete " + Constants.typeText[id.type] + " " 
-                    + Integer.toString(id.id) + " (handle " + id.handle + "): " 
+                    + Integer.toString(id.id) + ": " 
                     + ex.getMessage(), ex);
         }
     }
@@ -416,15 +416,17 @@ public class RDFConsumer implements Consumer
         int type;
         int id;
         String handle;
+        String[] identifiers;
         
-        DSOIdentifier(int type, int id, String handle)
+        DSOIdentifier(int type, int id, String handle, String[] identifiers)
         {
             this.type = type;
             this.id = id;
             this.handle = handle;
+            this.identifiers = identifiers;
         }
         
-        DSOIdentifier(DSpaceObject dso)
+        DSOIdentifier(DSpaceObject dso, Context ctx)
         {
             if (dso.getType() != Constants.SITE 
                     && dso.getType() != Constants.COMMUNITY
@@ -437,6 +439,7 @@ public class RDFConsumer implements Consumer
             this.type = dso.getType();
             this.id = dso.getID();
             this.handle = dso.getHandle();
+            this.identifiers = dso.getIdentifiers(ctx);
         }
         
         @Override

dspace-rdf/src/main/java/org/dspace/rdf/RDFUtil.java

@@ -81,10 +81,11 @@ public class RDFUtil {
      *         identifier assigned to the provided DSO.
      */
     public static String generateIdentifier(Context context, int type, int id,
-            String handle) throws SQLException
+            String handle, String[] identifier)
+            throws SQLException
     {
         return RDFConfiguration.getURIGenerator().generateIdentifier(context, 
-                type, id, handle);
+                type, id, handle, identifier);
     }
     /**
      * Converts the the provided DSpaceObject into RDF and returns the model.
@@ -281,11 +282,11 @@ public class RDFUtil {
      * @throws SQLException
      * @throws RDFMissingIdentifierException In case that no Identifier could be generated.
      */
-    public static void delete(Context ctx, int type, int id, String handle)
+    public static void delete(Context ctx, int type, int id, String handle, String[] identifiers)
             throws SQLException, RDFMissingIdentifierException
     {
         String uri = RDFConfiguration.getURIGenerator().generateIdentifier(ctx,
-                        type, id, handle);
+                        type, id, handle, identifiers);
         if (uri != null)
         {
             RDFConfiguration.getRDFStorage().delete(uri);

dspace-rdf/src/main/java/org/dspace/rdf/storage/DOIHandleURIGenerator.java

@@ -0,0 +1,22 @@
+/**
+ * The contents of this file are subject to the license and copyright
+ * detailed in the LICENSE and NOTICE files at the root of the source
+ * tree and available online at
+ *
+ * http://www.dspace.org/license/
+ */
+
+package org.dspace.rdf.storage;
+
+/**
+ * Extends the DOIURIGenerator but uses handles as fallback to DOIs.
+ * @author pbecker
+ */
+public class DOIHandleURIGenerator
+extends DOIURIGenerator
+implements URIGenerator
+{
+
+    protected final static URIGenerator fallback = new HandleURIGenerator();
+    
+}

dspace-rdf/src/main/java/org/dspace/rdf/storage/DOIURIGenerator.java

@@ -0,0 +1,70 @@
+/**
+ * The contents of this file are subject to the license and copyright
+ * detailed in the LICENSE and NOTICE files at the root of the source
+ * tree and available online at
+ *
+ * http://www.dspace.org/license/
+ */
+
+package org.dspace.rdf.storage;
+
+import org.apache.log4j.Logger;
+import org.dspace.content.DSpaceObject;
+import org.dspace.core.Constants;
+import org.dspace.core.Context;
+import org.dspace.identifier.DOI;
+import org.dspace.identifier.IdentifierException;
+
+import java.sql.SQLException;
+
+/**
+ *
+ * @author pbecker
+ */
+public class DOIURIGenerator
+implements URIGenerator
+{
+    private static final Logger log = Logger.getLogger(DOIURIGenerator.class);
+
+    /*
+     * Currently (August 31 2014, in preparation of DSpace 5.0) DSpace supports DOIs for items only. This fallback
+     * will be used to generate an URI, whenever no DOI was found that could be used to.
+     */
+    protected final static URIGenerator fallback = new LocalURIGenerator();
+    
+    @Override
+    public String generateIdentifier(Context context, int type, int id, String handle, String[] identifiers) throws SQLException {
+        if (type != Constants.SITE
+                && type != Constants.COMMUNITY
+                && type != Constants.COLLECTION
+                && type != Constants.ITEM)
+        {
+            return null;
+        }
+
+        String doi = null;
+        for (String identifier : identifiers)
+        {
+            try
+            {
+                doi = DOI.DOIToExternalForm(identifier);
+            } catch (IdentifierException ex) {
+                // identifier is not a DOI: no problem, keep on looking.
+            }
+        }
+        if (doi != null) {
+            return doi;
+        } else {
+            log.info("Didn't find a DOI for " + Constants.typeText[type] + ", id " + Integer.toString(id)
+                    + ", will use fallback URIGenerator.");
+            return fallback.generateIdentifier(context, type, id, handle, identifiers);
+        }
+    }
+
+    public String generateIdentifier(Context context, DSpaceObject dso)
+            throws SQLException
+    {
+        return generateIdentifier(context, dso.getType(), dso.getID(), dso.getHandle(), dso.getIdentifiers(context));
+    }
+    
+}

dspace-rdf/src/main/java/org/dspace/rdf/storage/HandleURIGenerator.java

@@ -24,7 +24,8 @@ import org.dspace.utils.DSpace;
 public class HandleURIGenerator implements URIGenerator {
     private static final Logger log = Logger.getLogger(HandleURIGenerator.class);
     
-    public String generateIdentifier(Context context, int type, int id, String handle)
+    public String generateIdentifier(Context context, int type, int id, 
+            String handle, String[] identifiers)
     {
         if (type == Constants.SITE)
         {
@@ -59,6 +60,7 @@ public class HandleURIGenerator implements URIGenerator {
             return null;
         }
         
-        return generateIdentifier(context, dso.getType(), dso.getID(), dso.getHandle());
+        return generateIdentifier(context, dso.getType(), dso.getID(), 
+                dso.getHandle(), dso.getIdentifiers(context));
     }
 }

dspace-rdf/src/main/java/org/dspace/rdf/storage/LocalURIGenerator.java

@@ -27,10 +27,10 @@ public class LocalURIGenerator implements URIGenerator {
     private static final Logger log = Logger.getLogger(LocalURIGenerator.class);
 
     @Override
-    public String generateIdentifier(Context context, int type, int id, String handle)
+    public String generateIdentifier(Context context, int type, int id, 
+            String handle, String[] identifiers)
             throws SQLException
     {
-        
         String urlPrefix = RDFConfiguration.getDSpaceRDFModuleURI() + "/resource/";
         
         if (type == Constants.SITE)
@@ -62,7 +62,7 @@ public class LocalURIGenerator implements URIGenerator {
             return null;
         }
         
-        return generateIdentifier(context, dso.getType(), dso.getID(), dso.getHandle());
+        return generateIdentifier(context, dso.getType(), dso.getID(), dso.getHandle(), dso.getIdentifiers(context));
     }
 
 }

dspace-rdf/src/main/java/org/dspace/rdf/storage/URIGenerator.java

@@ -40,7 +40,7 @@ public interface URIGenerator {
      * @return May return null, if no URI could be generated.
      * @see org.dspace.rdf.RDFUtil#generateIdentifier(Context, DSpaceObject)
      */
-    public String generateIdentifier(Context context, int type, int id, String handle)
+    public String generateIdentifier(Context context, int type, int id, String handle, String[] identifiers)
             throws SQLException;
     
     /**