Class Permissions

java.lang.Object
java.security.PermissionCollection
java.security.Permissions
All Implemented Interfaces:
Serializable
public final classPermissionsextendsPermissionCollectionimplementsSerializable
This class represents a heterogeneous collection of permissions. That is, it contains different types ofPermission objects, organized intoPermissionCollection objects. For example, if anyjava.io.FilePermission objects are added to an instance of this class, they are all stored in a singlePermissionCollection. It is thePermissionCollection returned by a call to thenewPermissionCollection method in theFilePermission class. Similarly, anyjava.lang.RuntimePermission objects are stored in thePermissionCollection returned by a call to thenewPermissionCollection method in theRuntimePermission class. Thus, this class represents a collection ofPermissionCollection objects.

When theadd method is called to add aPermission, thePermission is stored in the appropriatePermissionCollection. If no such collection exists yet, thePermission object's class is determined and thenewPermissionCollection method is called on that class to create thePermissionCollection and add it to thePermissions object. IfnewPermissionCollection returnsnull, then a defaultPermissionCollection that uses a hashtable will be created and used. Each hashtable entry stores aPermission object as both the key and the value.

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

Since:
1.2
See Also:

  • Constructor Details

    • Permissions

      public Permissions()
      Creates a newPermissions object containing noPermissionCollection objects.

  • Method Details

    • add

      public void add(Permission permission)
      Adds aPermission object to thePermissionCollection for the class the permission belongs to. For example, ifpermission is aFilePermission, it is added to theFilePermissionCollection stored in thisPermissions object. This method creates a newPermissionCollection object (and adds the permission to it) if an appropriate collection does not yet exist.
      Specified by:
      add in class PermissionCollection
      Parameters:
      permission - thePermission object to add.
      Throws:
      SecurityException - if thisPermissions object is marked as readonly.
      See Also:

    • implies

      public boolean implies(Permission permission)
      Checks to see if this object'sPermissionCollection for permissions of the specified permission's class implies the permissions expressed in thepermission object. Returnstrue if the combination of permissions in the appropriatePermissionCollection (e.g., aFilePermissionCollection for aFilePermission) together imply the specified permission.

      For example, suppose there is aFilePermissionCollection in thisPermissions object, and it contains oneFilePermission that specifies "read" access for all files in all subdirectories of the "/tmp" directory, and anotherFilePermission that specifies "write" access for all files in the "/tmp/scratch/foo" directory. Then if theimplies 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 thisPermissionCollection contains theAllPermission, this method will always returntrue.

      Specified by:
      implies in class PermissionCollection
      Parameters:
      permission - thePermission object to check.
      Returns:
      true if "permission" is implied by the permissions in thePermissionCollection it belongs to,false if not.

    • elements

      public Enumeration<Permission> elements()
      Returns an enumeration of all thePermission objects in all thePermissionCollection objects in thisPermissions object.
      Specified by:
      elements in class PermissionCollection
      Returns:
      an enumeration of all thePermission objects.
      See Also: