org.osgi.service.dmt

Class Acl

java.lang.Object

org.osgi.service.dmt.Acl

public final class Acl
extends Object

Acl is an immutable class representing structured access to DMT ACLs. Under OMA DM the ACLs are defined as strings with an internal syntax.

The methods of this class taking a principal as parameter accept remote server IDs (as passed to DmtAdmin.getSession), as well as " * " indicating any principal.

The syntax for valid remote server IDs:

<server-identifier> ::= All printable characters except '=', '&', '*', '+' or white-space characters.

Field Summary

Fields

Modifier and Type	Field and Description
static int	ADD Principals holding this permission can issue ADD commands on the node having this ACL.
static int	ALL_PERMISSION Principals holding this permission can issue any command on the node having this ACL.
static int	DELETE Principals holding this permission can issue DELETE commands on the node having this ACL.
static int	EXEC Principals holding this permission can issue EXEC commands on the node having this ACL.
static int	GET Principals holding this permission can issue GET command on the node having this ACL.
static int	REPLACE Principals holding this permission can issue REPLACE commands on the node having this ACL.

Constructor Summary

Constructors

Constructor and Description
Acl(String acl) Create an instance of the ACL from its canonical string representation.
Acl(String[] principals, int[] permissions) Creates an instance with a specified list of principals and the permissions they hold.

Method Summary

Methods

Modifier and Type	Method and Description
Acl	addPermission(String principal, int permissions) Create a new Acl instance from this Acl with the given permission added for the given principal.
Acl	deletePermission(String principal, int permissions) Create a new Acl instance from this Acl with the given permission revoked from the given principal.
boolean	equals(Object obj) Checks whether the given object is equal to this Acl instance.
int	getPermissions(String principal) Get the permissions associated to a given principal.
String[]	getPrincipals() Get the list of principals who have any kind of permissions on this node.
int	hashCode() Returns the hash code for this ACL instance.
boolean	isPermitted(String principal, int permissions) Check whether the given permissions are granted to a certain principal.
Acl	setPermission(String principal, int permissions) Create a new Acl instance from this Acl where all permissions for the given principal are overwritten with the given permissions.
String	toString() Give the canonical string representation of this ACL.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

GET

public static final int GET

Principals holding this permission can issue GET command on the node having this ACL.

See Also:

Constant Field Values

ADD

public static final int ADD

Principals holding this permission can issue ADD commands on the node having this ACL.

See Also:

Constant Field Values

REPLACE

public static final int REPLACE

Principals holding this permission can issue REPLACE commands on the node having this ACL.

See Also:

Constant Field Values

DELETE

public static final int DELETE

Principals holding this permission can issue DELETE commands on the node having this ACL.

See Also:

Constant Field Values

EXEC

public static final int EXEC

Principals holding this permission can issue EXEC commands on the node having this ACL.

See Also:

Constant Field Values

ALL_PERMISSION

public static final int ALL_PERMISSION

Principals holding this permission can issue any command on the node having this ACL. This permission is the logical OR of ADD, DELETE, EXEC, GET and REPLACE permissions.

See Also:

Constant Field Values

Constructor Detail

Acl

public Acl(String acl)

Create an instance of the ACL from its canonical string representation.

Parameters:

acl - The string representation of the ACL as defined in OMA DM. If null or empty then it represents an empty list of principals with no permissions.

Throws:

IllegalArgumentException - if acl is not a valid OMA DM ACL string

Acl

public Acl(String[] principals,
   int[] permissions)

Creates an instance with a specified list of principals and the permissions they hold. The two arrays run in parallel, that is principals[i] will hold permissions[i] in the ACL.

A principal name may not appear multiple times in the 'principals' argument. If the "*" principal appears in the array, the corresponding permissions will be granted to all principals (regardless of whether they appear in the array or not).

Parameters:

principals - The array of principals

permissions - The array of permissions

Throws:

IllegalArgumentException - if the length of the two arrays are not the same, if any array element is invalid, or if a principal appears multiple times in the principals array

Method Detail

equals

public boolean equals(Object obj)

Checks whether the given object is equal to this Acl instance. Two Acl instances are equal if they allow the same set of permissions for the same set of principals.

Overrides:

equals in class Object

Parameters:

obj - the object to compare with this Acl instance

Returns:

true if the parameter represents the same ACL as this instance

hashCode

public int hashCode()

Returns the hash code for this ACL instance. If two Acl instances are equal according to the equals(Object) method, then calling this method on each of them must produce the same integer result.

Overrides:

hashCode in class Object

Returns:

hash code for this ACL

addPermission

public Acl addPermission(String principal,
                int permissions)

Create a new Acl instance from this Acl with the given permission added for the given principal. The already existing permissions of the principal are not affected.

Parameters:

principal - The entity to which permissions should be granted, or "*" to grant permissions to all principals.

permissions - The permissions to be given. The parameter can be a logical or of more permission constants defined in this class.

Returns:

a new Acl instance

Throws:

IllegalArgumentException - if principal is not a valid principal name or if permissions is not a valid combination of the permission constants defined in this class

deletePermission

public Acl deletePermission(String principal,
                   int permissions)

Create a new Acl instance from this Acl with the given permission revoked from the given principal. Other permissions of the principal are not affected.

Note, that it is not valid to revoke a permission from a specific principal if that permission is granted globally to all principals.

Parameters:

principal - The entity from which permissions should be revoked, or "*" to revoke permissions from all principals.

permissions - The permissions to be revoked. The parameter can be a logical or of more permission constants defined in this class.

Returns:

a new Acl instance

Throws:

IllegalArgumentException - if principal is not a valid principal name, if permissions is not a valid combination of the permission constants defined in this class, or if a globally granted permission would have been revoked from a specific principal

getPermissions

public int getPermissions(String principal)

Get the permissions associated to a given principal.

Parameters:

principal - The entity whose permissions to query, or "*" to query the permissions that are granted globally, to all principals

Returns:

The permissions of the given principal. The returned int is a bitmask of the permission constants defined in this class

Throws:

IllegalArgumentException - if principal is not a valid principal name

isPermitted

public boolean isPermitted(String principal,
                  int permissions)

Check whether the given permissions are granted to a certain principal. The requested permissions are specified as a bitfield, for example (Acl.ADD | Acl.DELETE | Acl.GET).

Parameters:

principal - The entity to check, or "*" to check whether the given permissions are granted to all principals globally

permissions - The permissions to check

Returns:

true if the principal holds all the given permissions

Throws:

IllegalArgumentException - if principal is not a valid principal name or if permissions is not a valid combination of the permission constants defined in this class

setPermission

public Acl setPermission(String principal,
                int permissions)

Create a new Acl instance from this Acl where all permissions for the given principal are overwritten with the given permissions.

Note, that when changing the permissions of a specific principal, it is not allowed to specify a set of permissions stricter than the global set of permissions (that apply to all principals).

Parameters:

principal - The entity to which permissions should be granted, or "*" to globally grant permissions to all principals.

permissions - The set of permissions to be given. The parameter is a bitmask of the permission constants defined in this class.

Returns:

a new Acl instance

Throws:

IllegalArgumentException - if principal is not a valid principal name, if permissions is not a valid combination of the permission constants defined in this class, or if a globally granted permission would have been revoked from a specific principal

getPrincipals

public String[] getPrincipals()

Get the list of principals who have any kind of permissions on this node. The list only includes those principals that have been explicitly assigned permissions (so "*" is never returned), globally set permissions naturally apply to all other principals as well.

Returns:

The array of principals having permissions on this node.

toString

public String toString()

Give the canonical string representation of this ACL. The operations are in the following order: {Add, Delete, Exec, Get, Replace}, principal names are sorted alphabetically.

Overrides:

toString in class Object

Returns:

The string representation as defined in OMA DM.