public
interface
Acl
implements
Owner
| java.security.acl.Acl |
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:
Developers
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.
See also:
Public methods | |
|---|---|
abstract
boolean
|
addEntry(Principal caller, AclEntry entry)
Adds an ACL entry to this ACL. |
abstract
boolean
|
checkPermission(Principal principal, Permission permission)
Checks whether or not the specified principal has the specified permission. |
abstract
Enumeration<AclEntry>
|
entries()
Returns an enumeration of the entries in this ACL. |
abstract
String
|
getName()
Returns the name of this ACL. |
abstract
Enumeration<Permission>
|
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). |
abstract
boolean
|
removeEntry(Principal caller, AclEntry entry)
Removes an ACL entry from this ACL. |
abstract
void
|
setName(Principal caller, String name)
Sets the name of this ACL. |
abstract
String
|
toString()
Returns a string representation of the ACL contents. |
Inherited methods | |
|---|---|
 From
interface
java.security.acl.Owner
| |
boolean addEntry (Principal caller, AclEntry entry)
Adds an ACL entry to this ACL. An entry associates a principal (e.g., an individual or a group) with a set of permissions. Each principal can have at most one positive ACL entry (specifying permissions to be granted to the principal) and one negative ACL entry (specifying permissions to be denied). If there is already an ACL entry of the same type (negative or positive) already in the ACL, false is returned.
| Parameters | |
|---|---|
caller |
Principal:
the principal invoking this method. It must be an
owner of this ACL. |
entry |
AclEntry:
the ACL entry to be added to this ACL. |
| Returns | |
|---|---|
boolean |
true on success, false if an entry of the same type (positive or negative) for the same principal is already present in this ACL. |
| Throws | |
|---|---|
NotOwnerException |
if the caller principal is not an owner of this ACL. |
boolean checkPermission (Principal principal, Permission permission)
Checks whether or not the specified principal has the specified
permission. If it does, true is returned, otherwise false is returned.
More specifically, this method checks whether the passed permission
is a member of the allowed permission set of the specified principal.
The allowed permission set is determined by the same algorithm as is
used by the getPermissions method.
| Parameters | |
|---|---|
principal |
Principal:
the principal, assumed to be a valid authenticated
Principal. |
permission |
Permission:
the permission to be checked for. |
| Returns | |
|---|---|
boolean |
true if the principal has the specified permission, false otherwise. |
See also:
Enumeration<AclEntry> entries ()
Returns an enumeration of the entries in this ACL. Each element in the enumeration is of type AclEntry.
| Returns | |
|---|---|
Enumeration<AclEntry> |
an enumeration of the entries in this ACL. |
String getName ()
Returns the name of this ACL.
| Returns | |
|---|---|
String |
the name of this ACL. |
See also:
Enumeration<Permission> 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). This set of allowed permissions is calculated as follows:
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.
| Parameters | |
|---|---|
user |
Principal:
the principal whose permission set is to be returned. |
| Returns | |
|---|---|
Enumeration<Permission> |
the permission set specifying the permissions the principal is allowed. |
boolean removeEntry (Principal caller, AclEntry entry)
Removes an ACL entry from this ACL.
| Parameters | |
|---|---|
caller |
Principal:
the principal invoking this method. It must be an
owner of this ACL. |
entry |
AclEntry:
the ACL entry to be removed from this ACL. |
| Returns | |
|---|---|
boolean |
true on success, false if the entry is not part of this ACL. |
| Throws | |
|---|---|
NotOwnerException |
if the caller principal is not an owner of this Acl. |
void setName (Principal caller, String name)
Sets the name of this ACL.
| Parameters | |
|---|---|
caller |
Principal:
the principal invoking this method. It must be an
owner of this ACL. |
name |
String:
the name to be given to this ACL. |
| Throws | |
|---|---|
NotOwnerException |
if the caller principal is not an owner of this ACL. |
See also:
String toString ()
Returns a string representation of the ACL contents.
| Returns | |
|---|---|
String |
a string representation of the ACL contents. |