1 /* 2 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 package examples; 25 26 /** 27 * Two-dimensional coordinates that can be represented 28 * in either Cartesian or polar form. 29 */ 30 public interface Coords { 31 32 /** 33 * Returns the Cartesian x-coordinate. 34 * 35 * @return the Cartesian x-coordinate 36 */ 37 public double x(); 38 39 /** 40 * Returns the Cartesian y-coordinate. 41 * 42 * @return the Cartesian y-coordinate 43 */ 44 public double y(); 45 46 /** 47 * Returns the polar r-coordinate, or radius. 48 * 49 * @return the polar r-coordinate 50 */ 51 public double r(); 52 53 /** 54 * Returns the polar theta-coordinate, or angle. 55 * 56 * @return the polar theta-coordinate 57 */ 58 public double theta(); 59 60 /** 61 * Cartesian coordinates. 62 * 63 * @param x the x-coordinate 64 * @param y the y-coordinate 65 */ 66 public record Cartesian(double x, double y) implements Coords { 67 @Override 68 public double r() { 69 return Math.sqrt(x * x + y * y); 70 } 71 72 @Override 73 public double theta() { 74 return (x == 0) ? Math.PI / 2.d : Math.atan(y / x); 75 } 76 } 77 78 /** 79 * Polar coordinates. 80 * 81 * @param r the radius 82 * @param theta the angle 83 */ 84 public record Polar(double r, double theta) implements Coords { 85 @Override 86 public double x() { 87 return r * Math.cos(theta); 88 } 89 90 @Override 91 public double y() { 92 return r * Math.sin(theta); 93 } 94 } 95 }