@Override
    public void read(JmeImporter im) throws IOException {
        super.read(im);
        InputCapsule ic = im.getCapsule(this);
        light = (PointLight) ic.readSavable("light", null);
        init((int) shadowMapSize);
    }
sets the light to use for casting shadows with this processor

@param light the point light
jme3-core/src/main/java/com/jme3/shadow/PointLightShadowRenderer.java