  We show that the complex absorbing potential (CAP) method for computing
scattering resonances applies to an abstractly defined class of black box
perturbations of the Laplacian in $\mathbb{R}^n$ which can be analytically
extended from $\mathbb{R}^n$ to a conic neighborhood in $\mathbb{C}^n$ near
infinity. The black box setting allows a unifying treatment of diverse problems
ranging from obstacle scattering to scattering on finite volume surfaces.
