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Diffstat (limited to 'libjava/classpath/java/security/Permission.java')
-rw-r--r-- | libjava/classpath/java/security/Permission.java | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/libjava/classpath/java/security/Permission.java b/libjava/classpath/java/security/Permission.java new file mode 100644 index 00000000000..48f4d52a18c --- /dev/null +++ b/libjava/classpath/java/security/Permission.java @@ -0,0 +1,187 @@ +/* Permission.java -- The superclass for all permission objects + Copyright (C) 1998, 2001, 2002, 2005 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + +package java.security; + +import java.io.Serializable; + +/** + * This class is the abstract superclass of all classes that implement + * the concept of a permission. A permission consists of a permission name + * and optionally a list of actions that relate to the permission. The + * actual meaning of the name of the permission is defined only in the + * context of a subclass. It may name a resource to which access permissions + * are granted (for example, the name of a file) or it might represent + * something else entirely. Similarly, the action list only has meaning + * within the context of a subclass. Some permission names may have no + * actions associated with them. That is, you either have the permission + * or you don't. + * + * <p>The most important method in this class is <code>implies</code>. This + * checks whether if one has this permission, then the specified + * permission is also implied. As a conceptual example, consider the + * permissions "Read All Files" and "Read File foo". The permission + * "Read All Files" implies that the caller has permission to read the + * file foo. + * + * <p><code>Permission</code>'s must be immutable - do not change their + * state after creation. + * + * @author Aaron M. Renn (arenn@urbanophile.com) + * @see Permissions + * @see PermissionCollection + * @since 1.1 + * @status updated to 1.4 + */ +public abstract class Permission implements Guard, Serializable +{ + /** + * Compatible with JDK 1.1+. + */ + private static final long serialVersionUID = -5636570222231596674L; + + /** + * This is the name assigned to this permission object. + * + * @serial the name of the permission + */ + private String name; + + /** + * Create an instance with the specified name. + * + * @param name the permission name + */ + public Permission(String name) + { + this.name = name; + } + + /** + * This method implements the <code>Guard</code> interface for this class. + * It calls the <code>checkPermission</code> method in + * <code>SecurityManager</code> with this <code>Permission</code> as its + * argument. This method returns silently if the security check succeeds + * or throws an exception if it fails. + * + * @param obj the <code>Object</code> being guarded - ignored by this class + * @throws SecurityException if the security check fails + * @see GuardedObject + * @see SecurityManager#checkPermission(Permission) + */ + public void checkGuard(Object obj) + { + SecurityManager sm = System.getSecurityManager(); + if (sm != null) + sm.checkPermission(this); + } + + /** + * This method tests whether this <code>Permission</code> implies that the + * specified <code>Permission</code> is also granted. + * + * @param perm the <code>Permission</code> to test against + * @return true if perm is implied by this + */ + public abstract boolean implies(Permission perm); + + /** + * Check to see if this object equals obj. Use <code>implies</code>, rather + * than <code>equals</code>, when making access control decisions. + * + * @param obj the object to compare to + */ + public abstract boolean equals(Object obj); + + /** + * This method returns a hash code for this <code>Permission</code>. It + * must satisfy the contract of <code>Object.hashCode</code>: it must be + * the same for all objects that equals considers to be the same. + * + * @return a hash value + */ + public abstract int hashCode(); + + /** + * Get the name of this <code>Permission</code>. + * + * @return the name + */ + public final String getName() + { + return name; + } + + /** + * This method returns the list of actions for this <code>Permission</code> + * as a <code>String</code>. The string should be in canonical order, for + * example, both <code>new FilePermission(f, "write,read")</code> and + * <code>new FilePermission(f, "read,write")</code> have the action list + * "read,write". + * + * @return the action list for this <code>Permission</code> + */ + public abstract String getActions(); + + /** + * This method returns an empty <code>PermissionCollection</code> object + * that can store permissions of this type, or <code>null</code> if no + * such collection is defined. Subclasses must override this to provide + * an appropriate collection when one is needed to accurately calculate + * <code>implies</code>. + * + * @return a new <code>PermissionCollection</code> + */ + public PermissionCollection newPermissionCollection() + { + return null; + } + + /** + * This method returns a <code>String</code> representation of this + * <code>Permission</code> object. This is in the format: + * <code>'(' + getClass().getName() + ' ' + getName() + ' ' + getActions + * + ')'</code>. + * + * @return this object as a <code>String</code> + */ + public String toString() + { + return '(' + getClass().getName() + ' ' + getName() + ' ' + + getActions() + ')'; + } +} // class Permission |