This is the interface used for representing one entry in an Access
Control List (ACL).
An ACL can be thought of as a data structure with multiple ACL entry
objects. Each ACL entry object 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. Each principal can have at most one positive ACL entry
and one negative entry; that is, multiple positive or negative ACL
entries are not allowed for any principal.
Note: ACL entries are by default positive. An entry becomes a
negative entry only if the setNegativePermissions
method is called on it.
Specifies the principal for which permissions are granted or denied
by this ACL entry. If a principal was already set for this ACL entry,
false is returned, otherwise true is returned.
Parameters:
user - the principal to be set for this entry.
Returns:
true if the principal is set, false if there was
already a principal set for this entry.
Sets this ACL entry to be a negative one. That is, the associated
principal (e.g., a user or a group) will be denied the permission set
specified in the entry.
Note: ACL entries are by default positive. An entry becomes a
negative entry only if this setNegativePermissions
method is called on it.