程序包 java.security

类 Permissions

java.lang.Object

java.security.PermissionCollection

java.security.Permissions

所有已实现的接口:

Serializable

public final class Permissions
extends PermissionCollection
implements Serializable

This class represents a heterogeneous collection of Permissions. That is, it contains different types of Permission objects, organized into PermissionCollections. For example, if any java.io.FilePermission objects are added to an instance of this class, they are all stored in a single PermissionCollection. It is the PermissionCollection returned by a call to the newPermissionCollection method in the FilePermission class. Similarly, any java.lang.RuntimePermission objects are stored in the PermissionCollection returned by a call to the newPermissionCollection method in the RuntimePermission class. Thus, this class represents a collection of PermissionCollections.

When the add method is called to add a Permission, the Permission is stored in the appropriate PermissionCollection. If no such collection exists yet, the Permission object's class is determined and the newPermissionCollection method is called on that class to create the PermissionCollection and add it to the Permissions object. If newPermissionCollection returns null, then a default PermissionCollection that uses a hashtable will be created and used. Each hashtable entry stores a Permission object as both the key and the value.

Enumerations returned via the elements method are not fail-fast. Modifications to a collection should not be performed while enumerating over that collection.

另请参阅:

Permission, PermissionCollection, AllPermission

构造器概要

构造器

构造器	说明
Permissions()	Creates a new Permissions object containing no PermissionCollections.

方法概要

限定符和类型	方法	说明
void	add(Permission permission)	Adds a permission object to the PermissionCollection for the class the permission belongs to.
Enumeration<Permission>	elements()	Returns an enumeration of all the Permission objects in all the PermissionCollections in this Permissions object.
boolean	implies(Permission permission)	Checks to see if this object's PermissionCollection for permissions of the specified permission's class implies the permissions expressed in the permission object.

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

从类继承的方法 java.security.PermissionCollection

isReadOnly, setReadOnly

构造器详细资料

Permissions

public Permissions()

Creates a new Permissions object containing no PermissionCollections.

方法详细资料

add

public void add(Permission permission)

Adds a permission object to the PermissionCollection for the class the permission belongs to. For example, if permission is a FilePermission, it is added to the FilePermissionCollection stored in this Permissions object. This method creates a new PermissionCollection object (and adds the permission to it) if an appropriate collection does not yet exist.

指定者:

add 在类中 PermissionCollection

参数:

permission - the Permission object to add.

抛出:

SecurityException - if this Permissions object is marked as readonly.

另请参阅:

PermissionCollection.isReadOnly()

implies

public boolean implies(Permission permission)

Checks to see if this object's PermissionCollection for permissions of the specified permission's class implies the permissions expressed in the permission object. Returns true if the combination of permissions in the appropriate PermissionCollection (e.g., a FilePermissionCollection for a FilePermission) together imply the specified permission.

For example, suppose there is a FilePermissionCollection in this Permissions object, and it contains one FilePermission that specifies "read" access for all files in all subdirectories of the "/tmp" directory, and another FilePermission that specifies "write" access for all files in the "/tmp/scratch/foo" directory. Then if the implies method is called with a permission specifying both "read" and "write" access to files in the "/tmp/scratch/foo" directory, true is returned.

Additionally, if this PermissionCollection contains the AllPermission, this method will always return true.

指定者:

implies 在类中 PermissionCollection

参数:

permission - the Permission object to check.

返回:

true if "permission" is implied by the permissions in the PermissionCollection it belongs to, false if not.

elements

public Enumeration<Permission> elements()

Returns an enumeration of all the Permission objects in all the PermissionCollections in this Permissions object.

指定者:

elements 在类中 PermissionCollection

返回:

an enumeration of all the Permissions.