GUACAMOLE-360: Add convenience function for testing user identity.

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/apache/guacamole/auth/jdbc/activeconnection/ActiveConnectionPermissionService.java

@@ -97,7 +97,7 @@ public class ActiveConnectionPermissionService
                 permissions.add(new ObjectPermission(ObjectPermission.Type.READ, identifier));
 
                 // If we're an admin, or the connection is ours, then we can DELETE
-                if (isAdmin || (targetEntity.isUser() && targetEntity.getIdentifier().equals(record.getUsername())))
+                if (isAdmin || targetEntity.isUser(record.getUsername()))
                     permissions.add(new ObjectPermission(ObjectPermission.Type.DELETE, identifier));
 
             }

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/apache/guacamole/auth/jdbc/base/ModeledPermissions.java

@@ -105,6 +105,21 @@ public abstract class ModeledPermissions<ModelType extends EntityModel>
         return getModel().getEntityType() == EntityType.USER;
     }
 
+    /**
+     * Returns whether the underlying entity represents a specific user having
+     * the given username.
+     *
+     * @param username
+     *     The username of a user.
+     *
+     * @return
+     *     true if the underlying entity is a user that has the given username,
+     *     false otherwise.
+     */
+    public boolean isUser(String username) {
+        return isUser() && getIdentifier().equals(username);
+    }
+
     /**
      * Returns whether the underlying entity is a user group. Entities may be
      * either users or user groups.

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/apache/guacamole/auth/jdbc/permission/AbstractPermissionService.java

@@ -101,7 +101,7 @@ public abstract class AbstractPermissionService<PermissionSetType extends Permis
             throws GuacamoleException {
 
         // A user can always read their own permissions
-        if (targetEntity.isUser() && user.getUser().getIdentifier().equals(targetEntity.getIdentifier()))
+        if (targetEntity.isUser(user.getUser().getIdentifier()))
             return true;
         
         // A system adminstrator can do anything