3422. Except where otherwise provided by this Title, a final 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.
(Enacted 1872.)