Topic : JNDI Kaster Nurmukan

JNDI2(c)CDAC(Formerly NCST) What is JNDI? Naming and Directory Services Naming Concepts Issues JNDI Architecture Programming with JNDI Role of JNDI in J2EE

JNDI3(c)CDAC(Formerly NCST) Class.forName("com.microsoft.jdbc. sqlserver.SQLServerDriver"); cnn = DriverManager.getConnection ("jdbc:microsoft:sqlserver://siddh ant:1433",“username",“password");

JNDI4(c)CDAC(Formerly NCST) Context ctx = new InitialContext(); DataSource ds = (DataSource)ctx.lookup(“myname”); Connection con = ds.getConnection(“abc”,”***”);

JNDI5(c)CDAC(Formerly NCST) Java Naming and Directory Interface (JNDI) provides a standard interface for Java applications to access naming and directory services.

JNDI6(c)CDAC(Formerly NCST) Naming Service performs: – Binding: Associating names with objects – Lookup: Find an object based on a name. Examples: DNS and File systems Examples: – DNS – Filesystems

JNDI7(c)CDAC(Formerly NCST) Directory is a naming service that stores objects with attributes. – Usernames and passwords etc stored in attrs. Tree like structure

JNDI8(c)CDAC(Formerly NCST) Atomic name is a indivisible component of a name – in /etc/fstab, etc and fstab are atomic names. Compound name is zero or more atomic names put together. – /etc/fstab is a compound name

JNDI9(c)CDAC(Formerly NCST) Binding is an association of a name with an object. – Filename “autoexec.bat” has a binding to some file data on the disk. – “c:\windows” foldername is bound to a folder on your drive. Compound name such as /usr/people/ed/.cshrc consists of multiple bindings, one to usr, one to people, one to ed, and one to.cshrc.

JNDI10(c)CDAC(Formerly NCST) Contains zero or more bindings. – Each binding has a distinct atomic name. /etc contains files named mtab and exports. The /etc folder is a context containing bindings with atomic names mtab and exports. mtab and exports are each bound to a file on the disk.

JNDI11(c)CDAC(Formerly NCST) /usr – CONTEXT – /usr/people – SUB-CONTEXT – /usr/bin – SUB-CONTEXT – /usr/local – SUB-CONTEXT Each atomic name is bound to a sub-context the subfolder. Subcontext are full-fledged contexts Can contain more name-object bindings, such as other files or other folders.

JNDI12(c)CDAC(Formerly NCST) Naming system: A connected set of contexts. Namespace: all the names contained within that naming system.

JNDI13(c)CDAC(Formerly NCST) Starting point for exploring a namespace. Starting point for performing all naming and directory operations.

JNDI14(c)CDAC(Formerly NCST) Many naming and directory products. – Netscape Directory Server – MicrosoftActiveDirectory Various naming and directory protocols: Each directory standard has a different protocol for accessing the directory. – Lightweight Directory Access Protocol (LDAP) – Network Information System (NIS) – Novell’s Network Directory System (NDS) EveryDS has it’s ownAPI.

JNDI15(c)CDAC(Formerly NCST) Standard interface to interact with naming and directory systems. For Java programs. Provides common interface to disparate directories: Same API for LDAP and NIS NDS. Used in EJB, RMI-IIOP, JDBC for operations like locating entities i.e. Users, Machines (e.g. printer), Objects, Services (e.g. datasource) etc.

JNDI16(c)CDAC(Formerly NCST) The client API – Allow Java code to perform directory operations. The Service Provider: Driver The Service Provider Interface (SPI) – An interface to which naming and directory service vendors can plug in.

JNDI17(c)CDAC(Formerly NCST)

JNDI18(c)CDAC(Formerly NCST) The JNDI comprises of 5 packages javax.naming – Contains classes and interfaces for accessing naming services javax.naming.directory – Extends javax.naming and provides functionality to access directory services in addition to naming services

JNDI19(c)CDAC(Formerly NCST) javax.naming.event – Classes and interfaces for supporting event notification in naming and directory services javax.naming.ldap – Classes and interfaces for using features that are specific to LDAP v3 that are not already covered by the more generic javax.naming.directory javax.naming.spi – Vendors develop their naming/directory services conforming to SPI. Applications can then access these services through the JNDI API

JNDI20(c)CDAC(Formerly NCST) Used to acquire an initial context Implementation of the JNDI driver: Knows the specific semantics of a particular directory structure. bootstrapping. Necessary information for JNDI to acquire that initial context. – The IP address of the J2EE server – The port number that the J2EE server accepts – Any username/password necessary to use the J2EE server.

JNDI21(c)CDAC(Formerly NCST) javax.naming.Context ctx = new javax.naming.InitialContext (System.getProperties()); java -Djava.naming.factory.initial= com.sun.jndi.fscontext.RefFSContextFactory -Djava.naming.provider.url= file:c:\examples.InitCtx class of the JNDI driver provider URL: URL that the service provider accepts for bootstrapping.

JNDI22(c)CDAC(Formerly NCST) Methods invoked on a Context list() - list of contents available at the context. – names of objects bound to the JNDI tree – subcontexts. lookup() - look up objects bound to the JNDI tree – Return type is driver specific RMI-IIOP java.rmi.Remote file system java.io.File

JNDI23(c)CDAC(Formerly NCST) rename() - give a new name to a context – c:\temp to c:\tmp createSubcontext() - create a subcontext at the context – c:\foo\bar at the folder c:\foo. destroySubcontext() - destroy a subcontext of the context – Destroy c:\foo\bar from the folder c:\foo. bind() – associates a name to a content and stores it at the Context – JNDI drivers accept different parameters to bind() rebind() - forces a bind even if some object is already bound to the name.

JNDI24(c)CDAC(Formerly NCST) import javax.naming.*; public class Startup { public static void main(String args[]) throws Exception { AccountImpl acct_impl = new AccountImpl(); Context ctx = new InitialContext (System.getProperties()); ctx.rebind(“myname", acct_impl); }

JNDI25(c)CDAC(Formerly NCST) import javax.naming.*; import java.rmi.*; public class Client { public static void main (String[] args) throws Exception { Context ctx = new InitialContext (System.getProperties()); Object remoteObject = ctx.lookup(“myname"); Account account = (Account) javax.rmi.PortableRemoteObject.narrow ( remoteObject, Account.class); int b = account.method1(5));}}

JNDI26(c)CDAC(Formerly NCST) J2EE servers have a JNDI implementation. Used to Look up beans. Connect to resource factories – JDBC DataSource – Java Message Service (JMS) drivers Acquiring a reference to the Java Transaction API’s (JTA) UserTransaction interface.

JNDI27(c)CDAC(Formerly NCST) Mastering Enterprise JavaBeans by Ed Roman et. al. (Wiley) JNDI Tutorial on java.sun.com Java Server Programming J2EE Edition – Volume 1 – Wrox. Java Enterprise in a nutshell – David Flanagan et. Al. – O’reilly