Dream interpretation (pentakwilan mimpi) doesn't have an exact science (and we will never have one, because it is of the matters of ruh; and Allah SWT said regarding the matters of ruh, "They ask you [O Prophet] about ruh; say, 'Its nature is known only to my Lord, and you [O humanity] have been given but little knowledge'" [Quran, 17:85],) however, we do have 17 general guidelines from the Qur'an and Sunnah:
1. There are 3 types of dream that we common people (non-prophets) see, baik Muslim baik non-Muslim:
i. Dreams from Allah SWT - (1) these type of dreams are generally good and positive; (2) they come true; (3) they could be visions of the future (could be of tomorrow, next year, or 10 years down the line); and (4) they never terrify you
ii. Dreams from Shaytan - (1) they terrify you (nightmares); (2) they are never true - so don't act upon them; and (3) we should not tell anybody of the dream
iii. Dreams from our own imagination; (1) the sign of this dream is that it vanishes from our memory after a short while - after a few minutes or hours or days.
Sebagaimana sabda Nabi SAW, "Mimpi itu ada tiga macam: (1) Mimpi yang baik adalah khabar gembira (glad tidings) dari Allah. (2) Mimpi yang menakutkan atau menyedihkan datangnya dari syaitan. (3) Mimpi yang timbul kerana ilusi angan-angan, atau khayal seseorang. Maka kerana itu, jika kamu bermimpi yang tidak kamu senangi, bangunlah, kemudian solat, dan jangan menceritakannya kepada orang lain." [Sahih Muslim, Jilid 4, No.2111]
Atau dalam hadith lain, baginda SAW bersabda, "Mimpi yang baik itu dari Allah, sedang mimpi yang tak tentu itu dari syaitan. Kalau seseorang bermimpi dengan mimpi yang tak tentu, hendaklah ia berlindung (kepada Allah) dari mimpi itu (dengan berta'awudz) dan hendaklah meludah (meniup) ke sebelah kirinya, kerananya mimpi buruk itu tidak akan berbahaya kepadanya." [Sahih Bukhari, Jilid 4, No.1849]
As for the prophets, of course their dreams were all wahyu from Allah SWT.
And yes, even non-Muslims see true dreams. E.g. the dream of the Egyptian King during the time of Nabi Yusuf AS, the dreams of the two prisoners, both found in Surah Yusuf [12:36 & 12:43]; the dream of Atikah, the aunt of the Prophet SAW about the after-effects of the Battle of Badr (Perang Badar); and the dream of the grandfather of the Prophet SAW about the location of the Well of Zamzam; etc. They were all non-Muslims.
