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- All Superinterfaces:
- AttributeView,- FileAttributeView,- FileOwnerAttributeView
 
 public interface AclFileAttributeView extends FileOwnerAttributeView A file attribute view that supports reading or updating a file's Access Control Lists (ACL) or file owner attributes.ACLs are used to specify access rights to file system objects. An ACL is an ordered list of access-control-entries, each specifying aUserPrincipaland the level of access for that user principal. This file attribute view defines thegetAcl, andsetAclmethods to read and write ACLs based on the ACL model specified in RFC 3530: Network File System (NFS) version 4 Protocol. This file attribute view is intended for file system implementations that support the NFSv4 ACL model or have a well-defined mapping between the NFSv4 ACL model and the ACL model used by the file system. The details of such mapping are implementation dependent and are therefore unspecified.This class also extends FileOwnerAttributeViewso as to define methods to get and set the file owner.When a file system provides access to a set of file-systemsthat are not homogeneous then only some of the file systems may support ACLs. ThesupportsFileAttributeViewmethod can be used to test if a file system supports ACLs.InteroperabilityRFC 3530 allows for special user identities to be used on platforms that support the POSIX defined access permissions. The special user identities are "OWNER@", "GROUP@", and "EVERYONE@". When both theAclFileAttributeViewand thePosixFileAttributeVieware supported then these special user identities may be included in ACLentriesthat are read or written. The file system'sUserPrincipalLookupServicemay be used to obtain aUserPrincipalto represent these special identities by invoking thelookupPrincipalByNamemethod.Usage Example: Suppose we wish to add an entry to an existing ACL to grant "joe" access: // lookup "joe" UserPrincipal joe = file.getFileSystem().getUserPrincipalLookupService() .lookupPrincipalByName("joe"); // get view AclFileAttributeView view = Files.getFileAttributeView(file, AclFileAttributeView.class); // create ACE to give "joe" read access AclEntry entry = AclEntry.newBuilder() .setType(AclEntryType.ALLOW) .setPrincipal(joe) .setPermissions(AclEntryPermission.READ_DATA, AclEntryPermission.READ_ATTRIBUTES) .build(); // read ACL, insert ACE, re-write ACL List<AclEntry> acl = view.getAcl(); acl.add(0, entry); // insert before any DENY entries view.setAcl(acl);Dynamic AccessWhere dynamic access to file attributes is required, the attributes supported by this attribute view are as follows: Name Type "acl" List<AclEntry>"owner" UserPrincipalThe getAttributemethod may be used to read the ACL or owner attributes as if by invoking thegetAclorgetOwnermethods.The setAttributemethod may be used to update the ACL or owner attributes as if by invoking thesetAclorsetOwnermethods.Setting the ACL when creating a fileImplementations supporting this attribute view may also support setting the initial ACL when creating a file or directory. The initial ACL may be provided to methods such as createFileorcreateDirectoryas anFileAttributewithname"acl:acl"and avaluethat is the list ofAclEntryobjects.Where an implementation supports an ACL model that differs from the NFSv4 defined ACL model then setting the initial ACL when creating the file must translate the ACL to the model supported by the file system. Methods that create a file should reject (by throwing IOException) any attempt to create a file that would be less secure as a result of the translation.- Since:
- 1.7
 
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Method SummaryAll Methods Instance Methods Abstract Methods Modifier and Type Method Description List<AclEntry>getAcl()Reads the access control list.Stringname()Returns the name of the attribute view.voidsetAcl(List<AclEntry> acl)Updates (replace) the access control list.- 
Methods declared in interface java.nio.file.attribute.FileOwnerAttributeViewgetOwner, setOwner
 
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Method Detail- 
nameString name() Returns the name of the attribute view. Attribute views of this type have the name"acl".- Specified by:
- namein interface- AttributeView
- Specified by:
- namein interface- FileOwnerAttributeView
- Returns:
- the name of the attribute view
 
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getAclList<AclEntry> getAcl() throws IOException Reads the access control list.When the file system uses an ACL model that differs from the NFSv4 defined ACL model, then this method returns an ACL that is the translation of the ACL to the NFSv4 ACL model. The returned list is modifiable so as to facilitate changes to the existing ACL. The setAclmethod is used to update the file's ACL attribute.- Returns:
- an ordered list of entriesrepresenting the ACL
- Throws:
- IOException- if an I/O error occurs
- SecurityException- In the case of the default provider, a security manager is installed, and it denies- RuntimePermission- ("accessUserInformation")or its- checkReadmethod denies read access to the file.
 
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setAclvoid setAcl(List<AclEntry> acl) throws IOException Updates (replace) the access control list.Where the file system supports Access Control Lists, and it uses an ACL model that differs from the NFSv4 defined ACL model, then this method must translate the ACL to the model supported by the file system. This method should reject (by throwing IOException) any attempt to write an ACL that would appear to make the file more secure than would be the case if the ACL were updated. Where an implementation does not support a mapping ofAclEntryType.AUDITorAclEntryType.ALARMentries, then this method ignores these entries when writing the ACL.If an ACL entry contains a user-principalthat is not associated with the same provider as this attribute view thenProviderMismatchExceptionis thrown. Additional validation, if any, is implementation dependent.If the file system supports other security related file attributes (such as a file access-permissionsfor example), the updating the access control list may also cause these security related attributes to be updated.- Parameters:
- acl- the new access control list
- Throws:
- IOException- if an I/O error occurs or the ACL is invalid
- SecurityException- In the case of the default provider, a security manager is installed, it denies- RuntimePermission- ("accessUserInformation")or its- checkWritemethod denies write access to the file.
 
 
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