Weak compactness in nice Musielak-Orlicz spaces

We prove two weak compactness criteria in Musielak-Orlicz spaces for $N$-functions satisfying the ${\mathrm{\Delta }}_2$-condition. They extend criteria from Andô for Orlicz spaces to this setting of non-symmetrical Banach function spaces. As consequences, we prove criteria for a sequence in a Musielak-Orlicz space to be weakly convergent, and show that Musielak-Orlicz spaces with the subsequence splitting property are weakly Banach-Saks. The study includes the case of Musielak-Orlicz sequence spaces.