java.security
Class Policy
This is an abstract class for representing the system security policy for
a Java application environment (specifying which permissions are available
for code from various sources). That is, the security policy is represented
by a
Policy
subclass providing an implementation of the abstract
methods in this
Policy
class.
There is only one
Policy
object in effect at any given time.
The source location for the policy information utilized by the
Policy
object is up to the
Policy
implementation.
The policy configuration may be stored, for example, as a flat ASCII file, as
a serialized binary file of the
Policy
class, or as a database.
The currently-installed
Policy
object can be obtained by
calling the
getPolicy()
method, and it can be changed by a call
to the
setPolicy()
method (by code with permission to reset the
Policy
).
The
refresh()
method causes the policy object to refresh /
reload its current configuration.
This is implementation-dependent. For example, if the policy object stores
its policy in configuration files, calling
refresh()
will cause
it to re-read the configuration policy files. The refreshed policy may not
have an effect on classes in a particular
ProtectionDomain
. This is
dependent on the
Policy
provider's implementation of the
implies()
method and the
PermissionCollection
caching
strategy.
The default
Policy
implementation can be changed by setting
the value of the
"policy.provider"
security property (in the
Java security properties file) to the fully qualified name of the desired
Policy
implementation class. The Java security properties file
is located in the file named
<JAVA_HOME>/lib/security/java.security
, where
<JAVA_HOME>
refers to the directory where the
SDK was installed.
IMPLEMENTATION NOTE: This implementation attempts to read the
System property named
policy.provider
to find the concrete
implementation of the
Policy
. If/when this fails, it falls back
to a default implementation, which
allows everything.
Policy() - Constructs a new
Policy object.
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clone , equals , finalize , getClass , hashCode , notify , notifyAll , toString , wait , wait , wait |
Policy
public Policy()
Constructs a new Policy
object.
getPermissions
public abstract PermissionCollection getPermissions(CodeSource codesource)
Evaluates the global policy and returns a
PermissionCollection
object specifying the set of permissions allowed for code from the
specified code source.
codesource
- the CodeSource
associated with the caller. This
encapsulates the original location of the code (where the code came from)
and the public key(s) of its signer.
- the set of permissions allowed for code from codesource according
to the policy. The returned set of permissions must be a new mutable
instance and it must support heterogeneous
Permission
types.
getPermissions
public PermissionCollection getPermissions(ProtectionDomain domain)
Evaluates the global policy and returns a
PermissionCollection
object specifying the set of permissions allowed given the characteristics
of the protection domain.
- the set of permissions allowed for the domain according to the
policy. The returned set of permissions must be a new mutable instance and
it must support heterogeneous
Permission
types.
getPolicy
public static Policy getPolicy()
Returns the installed
Policy
object. This value should not be
cached, as it may be changed by a call to
setPolicy()
. This
method first calls
SecurityManager.checkPermission(Permission)
with
a
SecurityPermission("getPolicy")
permission to ensure it's ok
to get the
Policy
object.
SecurityException
- if a security manager exists and its
checkPermission()
method doesn't allow getting the
Policy
object.
refresh
public abstract void refresh()
Refreshes/reloads the policy configuration. The behavior of this method
depends on the implementation. For example, calling refresh on a file-based
policy will cause the file to be re-read.
setPolicy
public static void setPolicy(Policy policy)
policy
- the new system Policy
object.
SecurityException
- if a security manager exists and its
checkPermission()
method doesn't allow setting the
Policy
.
Policy.java --- Policy Manager Class
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