Discussion discussion =
this.discussionRepository()
.discussionOfId(new Tenant(aTenantId),
new DiscussionId(aDiscussionId));
Author author =
this.collaboratorService().authorFrom(new Tenant(aTenantId), anAuthorId);
Post post = discussion.post(this.forumIdentityService(), author, aSubject, aBodyText);
this.postRepository().save(post);