double getNumber(StreamTokenizer st) throws IOException
    {
        if (st.nextToken() != StreamTokenizer.TT_NUMBER) {
            System.err.println("ERROR: number expected in line "+st.lineno());
            throw new IOException(st.toString());
        }
        return st.nval;
    }

    void ReadInput(InputStream is) throws IOException
    {
	    StreamTokenizer st = new StreamTokenizer(is);
    	st.commentChar('#');
        scan: while (true) {
	        switch (st.nextToken()) {
	          default:
		        break scan;
	          case StreamTokenizer.TT_WORD:
	            if (st.sval.equals("sphere")) {
                    Vector3D v = new Vector3D((float) getNumber(st), (float) getNumber(st), (float) getNumber(st));
		            float r = (float) getNumber(st);
		            objectList.addElement(new Sphere(currentSurface, v, r));
			    } else
			    if (st.sval.equals("eye")) {
		            eye = new Vector3D((float) getNumber(st), (float) getNumber(st), (float) getNumber(st));
			    } else
			    if (st.sval.equals("lookat")) {
		            lookat = new Vector3D((float) getNumber(st), (float) getNumber(st), (float) getNumber(st));
			    } else
			    if (st.sval.equals("up")) {
		            up = new Vector3D((float) getNumber(st), (float) getNumber(st), (float) getNumber(st));
			    } else
			    if (st.sval.equals("fov")) {
                    fov = (float) getNumber(st);
			    } else
			    if (st.sval.equals("background")) {
                    background = new Color((float) getNumber(st), (float) getNumber(st), (float) getNumber(st));
			    } else
			    if (st.sval.equals("light")) {
			        float r = (float) getNumber(st);
			        float g = (float) getNumber(st);
			        float b = (float) getNumber(st);
		            if (st.nextToken() != StreamTokenizer.TT_WORD) {
                        throw new IOException(st.toString());
                    }
		            if (st.sval.equals("ambient")) {
		                lightList.addElement(new Light(Light.AMBIENT, null, r, g, b));
		            } else
		            if (st.sval.equals("directional")) {
		                Vector3D v = new Vector3D((float) getNumber(st), (float) getNumber(st), (float) getNumber(st));
		                lightList.addElement(new Light(Light.DIRECTIONAL, v, r, g, b));
		            } else
		            if (st.sval.equals("point")) {
		                Vector3D v = new Vector3D((float) getNumber(st), (float) getNumber(st), (float) getNumber(st));
		                lightList.addElement(new Light(Light.POINT, v, r, g, b));
		            } else {
		                System.err.println("ERROR: in line "+st.lineno()+" at "+st.sval);
		                throw new IOException(st.toString());
		            }
			    } else
			    if (st.sval.equals("surface")) {
			        float r = (float) getNumber(st);
			        float g = (float) getNumber(st);
			        float b = (float) getNumber(st);
		            float ka = (float) getNumber(st);
		            float kd = (float) getNumber(st);
		            float ks = (float) getNumber(st);
		            float ns = (float) getNumber(st);
		            float kr = (float) getNumber(st);
		            float kt = (float) getNumber(st);
		            float index = (float) getNumber(st);
		            currentSurface = new Surface(r, g, b, ka, kd, ks, ns, kr, kt, index);
			    }
			    break;
	        }
	    }
        is.close();
	    if (st.ttype != StreamTokenizer.TT_EOF)
	        throw new IOException(st.toString());
	}

An example input file:

eye 0 3 10
lookat 0 -1 0
up 0 1 0
fov 30
background 0.2 0.8 0.9
light 1 1 1 ambient
light 1 1 1 directional -1 -2 -1
light 0.5 0.5 0.5 point -1 2 -1

surface 0.7 0.2 0.8 0.5 0.4 0.2 10.0 0.0 0.0 1.0
sphere -2 -3 -2 1.5
sphere  0 -3 -2 1.5
sphere  2 -3 -2 1.5
sphere -1 -3 -1 1.5
sphere  1 -3 -1 1.5
sphere -2 -3  0 1.5
sphere  0 -3  0 1.5
sphere  2 -3  0 1.5
sphere -1 -3  1 1.5
sphere  1 -3  1 1.5
sphere -2 -3  2 1.5
sphere  0 -3  2 1.5
sphere  2 -3  2 1.5

surface 0.7 0.2 0.2 0.5 0.4 0.2 3.0 0.0 0.0 1.0
sphere -1 -3 -2 1.5
sphere  1 -3 -2 1.5
sphere -2 -3 -1 1.5
sphere  0 -3 -1 1.5
sphere  2 -3 -1 1.5
sphere -1 -3  0 1.5
sphere  1 -3  0 1.5
sphere -2 -3  1 1.5
sphere  0 -3  1 1.5
sphere  2 -3  1 1.5
sphere -1 -3  2 1.5
sphere  1 -3  2 1.5

surface 0.4 0.4 0.4 0.1 0.1 0.6 100.0 0.8 0.0 1.0
sphere  0 0 0 1