Java™ Platform
Standard Ed. 6

java.security.acl
Interface Acl

All Superinterfaces:
Owner

public interface Acl
extends Owner

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:

The 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:
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<AclEntry> entries()
          Returns an enumeration of the entries in this ACL.
 String getName()
          Returns the name of this ACL.
 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).
 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

setName

void setName(Principal caller,
             String name)
             throws NotOwnerException
Sets the name of this ACL.

Parameters:
caller - the principal invoking this method. It must be an owner of this ACL.
name - the name to be given to this ACL.
Throws:
NotOwnerException - if the caller principal is not an owner of this ACL.
See Also:
getName()

getName

String getName()
Returns the name of this ACL.

Returns:
the name of this ACL.
See Also:
setName(java.security.Principal, java.lang.String)

addEntry

boolean addEntry(Principal caller,
                 AclEntry entry)
                 throws NotOwnerException
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 - the principal invoking this method. It must be an owner of this ACL.
entry - the ACL entry to be added to this ACL.
Returns:
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.

removeEntry

boolean removeEntry(Principal caller,
                    AclEntry entry)
                    throws NotOwnerException
Removes an ACL entry from this ACL.

Parameters:
caller - the principal invoking this method. It must be an owner of this ACL.
entry - the ACL entry to be removed from this ACL.
Returns:
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.

getPermissions

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:

Parameters:
user - the principal whose permission set is to be returned.
Returns:
the permission set specifying the permissions the principal is allowed.

entries

Enumeration<AclEntry> entries()
Returns an enumeration of the entries in this ACL. Each element in the enumeration is of type AclEntry.

Returns:
an enumeration of the entries in this ACL.

checkPermission

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 - the principal, assumed to be a valid authenticated Principal.
permission - the permission to be checked for.
Returns:
true if the principal has the specified permission, false otherwise.
See Also:
getPermissions(java.security.Principal)

toString

String toString()
Returns a string representation of the ACL contents.

Overrides:
toString in class Object
Returns:
a string representation of the ACL contents.

Java™ Platform
Standard Ed. 6

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For further API reference and developer documentation, see Java SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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