[WIP] CODENVY-627 Check for reserved usernames on user creation

wsmaster/che-core-api-user/src/main/java/org/eclipse/che/api/user/server/UserManager.java

@@ -10,6 +10,9 @@
  *******************************************************************************/
 package org.eclipse.che.api.user.server;
 
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Sets;
+
 import org.eclipse.che.api.core.ConflictException;
 import org.eclipse.che.api.core.NotFoundException;
 import org.eclipse.che.api.core.ServerException;
@@ -22,9 +25,12 @@
 import org.slf4j.LoggerFactory;
 
 import javax.inject.Inject;
+import javax.inject.Named;
 
+import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Set;
 
 import static com.google.common.base.MoreObjects.firstNonNull;
 import static java.lang.String.format;
@@ -45,15 +51,17 @@ public class UserManager {
     private final UserDao        userDao;
     private final UserProfileDao profileDao;
     private final PreferenceDao  preferenceDao;
-
+    private final Set<String>    reservedNames;
 
     @Inject
     public UserManager(UserDao userDao,
                        UserProfileDao profileDao,
-                       PreferenceDao preferenceDao) {
+                       PreferenceDao preferenceDao,
+                       @Named("user.reserved_names") String[] reservedNames) {
         this.userDao = userDao;
         this.profileDao = profileDao;
         this.preferenceDao = preferenceDao;
+        this.reservedNames = Sets.newHashSet(reservedNames);
     }
 
 
@@ -68,6 +76,9 @@ public UserManager(UserDao userDao,
      *         when any other error occurs
      */
     public void create(User user, boolean isTemporary) throws ConflictException, ServerException {
+        if (isNameReserved(user.getName())) {
+            throw new ConflictException("Username is reserved");
+        }
         user.withId(generate("user", ID_LENGTH))
             .withPassword(firstNonNull(user.getPassword(), generate("", PASSWORD_LENGTH)));
         userDao.create(user);
@@ -164,4 +175,8 @@ public User getByName(String userName) throws NotFoundException, ServerException
     public void remove(String id) throws NotFoundException, ServerException, ConflictException {
         userDao.remove(id);
     }
+
+    private boolean isNameReserved(String name) {
+        return reservedNames.contains(name);
+    }
 }