TheHighScorePermissionclass defines the permission thatTerrysGameneeds to update the user's high score.All permission classes should subclass from either
java.security.Permissionorjava.security.BasicPermission. The basic difference between the two is thatjava.security.Permissiondefines more complex permissions that require names and actions. For example, ajava.io.FilePermissionextends fromjava.security.Permission, and requires a name (a filename), and actions allowed for that file (read/write/delete).In contrast,
java.security.BasicPermissiondefines simpler permissions that only require a name. For example,java.lang.RuntimePermissionextends fromjava.security.BasicPermissionand simply needs a name (like "exitVM"), which allows programs to exit the Java Virtual Machine.Our
HighScorePermissionis a simple permission, and hence can be extended fromjava.security.BasicPermission.Often, the method implementations in the
BasicPermissionclass itself do not need to be overridden by its subclasses. That is the case with ourHighScorePermission, so all we need to implement are the constructors, which just invoke the superclass constructors, as shown in thefollowing:
/* * Copyright (c) 1995 - 2008 Sun Microsystems, Inc. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * - Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * - Neither the name of Sun Microsystems nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ package com.scoredev.scores; import java.security.*; public final class HighScorePermission extends BasicPermission { public HighScorePermission(String name) { super(name); } // note that actions is ignored and not used, // but this constructor is still needed public HighScorePermission(String name, String actions) { super(name, actions); } }