[sdk] Tweak UnindexReport interface and fix error file count

- provide clearer methods to collect the counts
  of files which were not unindexed successfully

dicoogle/src/main/java/pt/ua/dicoogle/server/web/servlets/management/UnindexServlet.java

@@ -121,8 +121,8 @@ protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws S
             for (Task<UnindexReport> task: tasks) {
                 try {
                     UnindexReport report = task.get();
-                    indexed = uris.size() - report.errorCount();
-                    failed = report.getUnindexFailures().size();
+                    indexed = uris.size() - report.notUnindexedFileCount();
+                    failed = report.failedFileCount();
                     notfound = report.getNotFound().size();
                 } catch (Exception ex) {
                     logger.error("Task to unindex items in {} failed", providers.get(i), ex);

sdk/src/main/java/pt/ua/dicoogle/sdk/datastructs/UnindexReport.java

@@ -130,10 +130,30 @@ public Collection<URI> getNotFound() {
         return Collections.unmodifiableCollection(this.notFound);
     }
 
-    /** Returns the total count of errors reported during unindexing
-     * due to either not having been found or other failures.
+    /** Returns the total count of failures reported during unindexing.
+     *
+     * Note that this does not necessarily correspond to
+     * the number of files affected,
+     * and does not include files which were not found.
+     */
+    public long failureCount() {
+        return this.failures.size();
+    }
+
+    /** Returns the total count of files which were not unindexed,
+     * whether because they were not found
+     * or could not be unindexed for other reasons.
+     */
+    public long notUnindexedFileCount() {
+        return this.notFound.size() + failedFileCount();
+    }
+
+    /** Returns the total count of files which failed to unindexed
+     * for reasons other than the files not being found.
      */
-    public long errorCount() {
-        return this.failures.size() + this.notFound.size();
+    public long failedFileCount() {
+        return this.failures.stream()
+                .mapToLong(f -> f.urisAffected.size())
+                .sum();
     }
 }