Tractate Makhshirin - Chapter 3 - Mishnah 6 מכשירין פרק ג׳ משנה ו׳

If his olives were put on the roof and rain came down upon them and he was glad of it, it comes under the law of ‘if water be put’. Rabbi Judah said: one cannot help being glad of it. Rather, [it comes under the law] only if he plugged up the gutter or if he shook the water [onto the olives].