Module java.base

Package java.nio.file.attribute

Class UserPrincipalLookupService

java.lang.Object

java.nio.file.attribute.UserPrincipalLookupService

public abstract class UserPrincipalLookupService
extends Object

An object to lookup user and group principals by name. A UserPrincipal represents an identity that may be used to determine access rights to objects in a file system. A GroupPrincipal represents a group identity. A UserPrincipalLookupService defines methods to lookup identities by name or group name (which are typically user or account names). Whether names and group names are case sensitive or not depends on the implementation. The exact definition of a group is implementation specific but typically a group represents an identity created for administrative purposes so as to determine the access rights for the members of the group. In particular it is implementation specific if the namespace for names and groups is the same or is distinct. To ensure consistent and correct behavior across platforms it is recommended that this API be used as if the namespaces are distinct. In other words, the lookupPrincipalByName should be used to lookup users, and lookupPrincipalByGroupName should be used to lookup groups.

Since:

1.7

See Also:

• FileSystem.getUserPrincipalLookupService()

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	UserPrincipalLookupService()	Initializes a new instance of this class.

Method Summary

Modifier and Type	Method	Description
abstract GroupPrincipal	lookupPrincipalByGroupName(String group)	Lookup a group principal by group name.
abstract UserPrincipal	lookupPrincipalByName(String name)	Lookup a user principal by name.

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

UserPrincipalLookupService

protected UserPrincipalLookupService()

Initializes a new instance of this class.

Method Details

lookupPrincipalByName

public abstract UserPrincipal lookupPrincipalByName(String name)
                                             throws IOException

Lookup a user principal by name.

Parameters:

name - the string representation of the user principal to lookup

Returns:

a user principal

Throws:

UserPrincipalNotFoundException - the principal does not exist

IOException - if an I/O error occurs

SecurityException - In the case of the default provider, and a security manager is installed, it checks RuntimePermission("lookupUserInformation")

lookupPrincipalByGroupName

public abstract GroupPrincipal lookupPrincipalByGroupName(String group)
                                                   throws IOException

Lookup a group principal by group name.

Where an implementation does not support any notion of group then this method always throws UserPrincipalNotFoundException. Where the namespace for user accounts and groups is the same, then this method is identical to invoking lookupPrincipalByName.

Parameters:

group - the string representation of the group to lookup

Returns:

a group principal

Throws:

UserPrincipalNotFoundException - the principal does not exist or is not a group

IOException - if an I/O error occurs

SecurityException - In the case of the default provider, and a security manager is installed, it checks RuntimePermission("lookupUserInformation")