Except where otherwise provided by this chapter, a permanent injunction may be granted to prevent the breach of an obligation existing in favor of the applicant:
(1) Where pecuniary compensation would not afford adequate relief;
(2) Where it would be extremely difficult to ascertain the amount of compensation which would afford adequate relief;
(3) Where the restraint is necessary to prevent a multiplicity of judicial proceedings; or
(4) Where the obligation arises from a trust.