The ornamental design for a rollerapplicator, as shown and described.
FIG. 1 is a front left perspective view of a roller applicator showing my new design;
FIG. 2 is a right side view thereof;
FIG. 3 is a left side view thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a rear view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The dotted broken lines immediately adjacent to the shaded areas of the roller applicator represent unclaimed boundaries of the claimed design. The dotted broken lines showing the remainder of the roller applicator are for illustrative purposes only and form no part of the claimed design.