This class
represents a security policy that determines the permissions granted
to code based on its source and signers, and, in Java 1.4 and later,
based on the user on whose behalf that code is running. There is only
a single Policy in effect at any one time. Obtain
the system policy by calling the static getPolicy(
) method. Code that has appropriate permissions can specify
a new system policy by calling setPolicy( ). The
refresh( ) method is a request to a
Policy object to update its state (for example, by
rereading its configuration file). The Policy
class is used primarily by system-level code. Applications should not
need to use this class unless they implement some kind of custom
access-control mechanism.Prior to Java 1.4, this class provides a mapping from
CodeSource objects to
PermissionCollection objects.
getPermissions( ) is
the central Policy method; it evaluates the
Policy for a given CodeSource
and returns an appropriate PermissionCollection
representing the static set of permissions available to code from
that source.As of Java 1.4, you can use a ProtectionDomain
object to encapsulate a CodeSource and a set of
users on whose behalf the code is running. In this release, there is
a new getPermissions( ) method that returns a
PermissionsCollection appropriate for the
specified ProtectionDomain. In addition, there is
a new implies( ) method that dynamically queries
the Policy to see if the specified permission is
granted to the specific ProtectionDomain.public abstract class Policy {
// Public Constructors
public Policy ( );
// Public Class Methods
public static java.security.Policy getPolicy ( );
public static void setPolicy (java.security.Policy p );
// Public Instance Methods
public abstract PermissionCollection getPermissions (CodeSource codesource );
1.4 public PermissionCollection getPermissions (ProtectionDomain domain );
1.4 public boolean implies (ProtectionDomain domain , Permission permission );
public abstract void refresh ( );
}
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