No court of the United States shall have jurisdiction to issue a temporary or permanent injunction in any case involving or growing out of a labor dispute, as defined in this chapter, except after hearing the testimony of witnesses in open court (with opportunity for cross-examination) in support of the allegations of a complaint made under oath, and testimony in opposition thereto, if offered, and except after findings of fact by the court, to the effect—
((a)) That unlawful acts have been threatened and will be committed unless restrained or have been committed and will be continued unless restrained, but no injunction or temporary restraining order shall be issued on account of any threat or unlawful act excepting against the person or persons, association, or organization making the threat or committing the unlawful act or actually authorizing or ratifying the same after actual knowledge thereof;
((b)) That substantial and irreparable injury to complainant’s property will follow;
((c)) That as to each item of relief granted greater injury will be inflicted upon complainant by the denial of relief than will be inflicted upon defendants by the granting of relief;
((d)) That complainant has no adequate remedy at law; and
((e)) That the public officers charged with the duty to protect complainant’s property are unable or unwilling to furnish adequate protection.