[#33] Fix implementation of updateUser

- remove validation check if old and new institutions are the same
- use variable "original" to update the institution
- log trace level message about the update only if old and new institutions are different
- add method to check if HasUri entities are equal by URI
- add method to get the URI of HasUri entity

src/main/java/cz/cvut/kbss/study/rest/OidcUserController.java

@@ -3,6 +3,7 @@
 import cz.cvut.kbss.study.exception.NotFoundException;
 import cz.cvut.kbss.study.model.Institution;
 import cz.cvut.kbss.study.model.User;
+import cz.cvut.kbss.study.model.util.HasUri;
 import cz.cvut.kbss.study.rest.exception.BadRequestException;
 import cz.cvut.kbss.study.security.SecurityConstants;
 import cz.cvut.kbss.study.service.InstitutionService;
@@ -14,10 +15,9 @@
 import org.springframework.web.bind.annotation.*;
 
 import java.net.URI;
-import java.util.Arrays;
 import java.util.List;
 import java.util.Objects;
-import java.util.stream.Collectors;
+import java.util.Optional;
 
 /**
  * API for getting basic user info.
@@ -74,23 +74,35 @@ public void updateUser(@PathVariable("username") String username, @RequestBody U
         final User original = getByUsername(username);
 
         assert original != null;
+        Institution newInstitution = user.getInstitution();
+        Institution oldInstitution = original.getInstitution();
+        original.setInstitution(newInstitution);
+        userService.update(original, sendEmail, "profileUpdate");
 
-        // validate institution update is valid
-        List<URI> institutionURIs = Arrays.asList(user.getInstitution(), original.getInstitution())
-                .stream().map(i -> i != null ? i.getUri() : null).collect(Collectors.toList());
-        if (Objects.equals(institutionURIs.get(0), institutionURIs.get(1))){
-            LOG.warn("Ignoring attempt to add user {} to institution {} because it is already in institution {}.", user, institutionURIs.get(0), institutionURIs.get(1));
-            return;
+        if (LOG.isTraceEnabled() && ! equals(newInstitution, oldInstitution)) {
+            LOG.trace("Set user institution {} to institution {} successfully.", user, oldInstitution, newInstitution);
         }
+    }
 
-        // make sure only institution is updated
-        Institution newInstitution = user.getInstitution();
-        user = original.copy();
-        user.setInstitution(newInstitution);
-        userService.update(user, sendEmail, "profileUpdate");
-        if (LOG.isTraceEnabled()) {
-            LOG.trace("Added user {} to institution {} successfully.", user, user.getInstitution());
-        }
+    /**
+     * Input arguments can be null and getUri can be null.
+     * @param entity1
+     * @param entity2
+     * @return true if the URIs of the input arguments are equal, false otherwise.
+     */
+    private boolean equals(HasUri entity1, HasUri entity2){
+        URI u1 = getURI(entity1);
+        URI u2 = getURI(entity2);
+        return Objects.equals(u1, u2);
+    }
+
+    /**
+     * Retrieves the URI of entity argument. entity can be null.
+     * @param entity
+     * @return the URI of the entity or null if entity is null.
+     */
+    private URI getURI(HasUri entity){
+        return Optional.of(entity).map(HasUri::getUri).orElse(null);
     }
 
     private List<User> getByInstitution(String institutionKey) {