Module java.base
Package java.security

Class Permissions

  • All Implemented Interfaces:
    Serializable

    public final classPermissionsextendsPermissionCollectionimplementsSerializable
    This class represents a heterogeneous collection of Permissions. That is, it contains different types of Permission objects, organized into PermissionCollections. For example, if anyjava.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 thenewPermissionCollection method in the FilePermission class. Similarly, anyjava.lang.RuntimePermission objects are stored in the PermissionCollection returned by a call to thenewPermissionCollection method in the RuntimePermission class. Thus, this class represents a collection of PermissionCollections.

    When theadd 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 thenewPermissionCollection method is called on that class to create the PermissionCollection and add it to the Permissions object. IfnewPermissionCollection 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 theelements method are notfail-fast. Modifications to a collection should not be performed while enumerating over that collection.

    See Also:
    Permission,PermissionCollection,AllPermission

    • Constructor Detail

      • Permissions

        public Permissions()
        Creates a new Permissions object containing no PermissionCollections.

    • Method Detail

      • add

        public void add(Permission permission)
        Adds a permission object to the PermissionCollection for the class the permission belongs to. For example, ifpermission 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.
        Specified by:
        add in class PermissionCollection
        Parameters:
        permission - the Permission object to add.
        Throws:
        SecurityException - if this Permissions object is marked as readonly.
        See Also:
        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 thepermission 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 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 this PermissionCollection contains the AllPermission, this method will always return true.

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