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JavaTM 2 Platform Std. Ed. v1.3.1 |
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Interface representing an Access Control List (ACL). An Access Control List is a data structure used to guard access to resources.
An ACL can be thought of as a data structure with multiple ACL entries. Each ACL entry, of interface type AclEntry, contains a set of permissions associated with a particular principal. (A principal represents an entity such as an individual user or a group). Additionally, each ACL entry is specified as being either positive or negative. If positive, the permissions are to be granted to the associated principal. If negative, the permissions are to be denied.
The ACL Entries in each ACL observe the following rules:
java.security.acl
package provides the
interfaces to the ACL and related data structures (ACL entries,
groups, permissions, etc.), and the sun.security.acl
classes provide a default implementation of the interfaces. For
example, java.security.acl.Acl
provides the
interface to an ACL and the sun.security.acl.AclImpl
class provides the default implementation of the interface.
The java.security.acl.Acl
interface extends the
java.security.acl.Owner
interface. The Owner
interface is used to maintain a list of owners for each ACL. Only
owners are allowed to modify an ACL. For example, only an owner can
call the ACL's addEntry
method to add a new ACL entry
to the ACL.
AclEntry
,
Owner
,
getPermissions(java.security.Principal)
Method Summary | |
boolean |
addEntry(Principal caller,
AclEntry entry)
Adds an ACL entry to this ACL. |
boolean |
checkPermission(Principal principal,
Permission permission)
Checks whether or not the specified principal has the specified permission. |
Enumeration |
entries()
Returns an enumeration of the entries in this ACL. |
String |
getName()
Returns the name of this ACL. |
Enumeration |
getPermissions(Principal user)
Returns an enumeration for the set of allowed permissions for the specified principal (representing an entity such as an individual or a group). |
boolean |
removeEntry(Principal caller,
AclEntry entry)
Removes an ACL entry from this ACL. |
void |
setName(Principal caller,
String name)
Sets the name of this ACL. |
String |
toString()
Returns a string representation of the ACL contents. |
Methods inherited from interface java.security.acl.Owner |
addOwner, deleteOwner, isOwner |
Method Detail |
public void setName(Principal caller, String name) throws NotOwnerException
caller
- the principal invoking this method. It must be an
owner of this ACL.name
- the name to be given to this ACL.NotOwnerException
- if the caller principal
is not an owner of this ACL.public String getName()
public boolean addEntry(Principal caller, AclEntry entry) throws NotOwnerException
caller
- the principal invoking this method. It must be an
owner of this ACL.entry
- the ACL entry to be added to this ACL.NotOwnerException
- if the caller principal
is not an owner of this ACL.public boolean removeEntry(Principal caller, AclEntry entry) throws NotOwnerException
caller
- the principal invoking this method. It must be an
owner of this ACL.entry
- the ACL entry to be removed from this ACL.NotOwnerException
- if the caller principal is not
an owner of this Acl.public Enumeration getPermissions(Principal user)
The individual positive and negative permission sets are also determined. The positive permission set contains the permissions specified in the positive ACL entry (if any) for the principal. Similarly, the negative permission set contains the permissions specified in the negative ACL entry (if any) for the principal. The individual positive (or negative) permission set is considered to be null if there is not a positive (negative) ACL entry for the principal in this ACL.
The set of permissions granted to the principal is then calculated using the simple rule that individual permissions always override the group permissions. That is, the principal's individual negative permission set (specific denial of permissions) overrides the group positive permission set, and the principal's individual positive permission set overrides the group negative permission set.
user
- the principal whose permission set is to be returned.public Enumeration entries()
public boolean checkPermission(Principal principal, Permission permission)
getPermissions
method.principal
- the principal, assumed to be a valid authenticated
Principal.permission
- the permission to be checked for.getPermissions(java.security.Principal)
public String toString()
toString
in class Object
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JavaTM 2 Platform Std. Ed. v1.3.1 |
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