| CONTENTS | PREV | NEXT |
Directory services play a vital role in Intranets and Internets by providing access to a variety of information about users, machines, networks, services, and applications. By its very nature, a directory service incorporates a naming facility for providing human understandable namespaces that characterize the arrangement and identification of the various entities.
The computing environment of an enterprise typically consists of several naming facilities often representing different parts of a composite namespace. For example, the Internet Domain Name System (DNS) might be used as the top-level naming facility for different organizations within an enterprise. The organizations themselves might use a directory service such as LDAP or NDS or NIS. From a user's perspective, there is one namespace consisting of composite names. URLs are examples of composite names because they span namespaces of multiple naming facilities. Applications which use directory services must support this user perspective.
Many Java application developers can benefit from a directory service API that is not only independent of the particular directory or naming service implementation, but also enables seamless access to directory objects through multiple naming facilities. In fact, any application can attach its own objects to the namespace. Such a facility enables any Java application to discover and retrieve objects of any type.
End users can benefit from logical namespaces that allow easier discovery and identification of the objects in the network.
Directory service developers can benefit from a service-provider capability that enables them to incorporate their respective implementations without requiring changes to the client.
Java Naming and Directory Interface (JNDI) is an API that provides directory and naming functionality to Java applications. It is defined to be independent of any specific directory service implementation. Thus, a variety of directories can be accessed in a common way.
Here are two examples to briefly illustrate some of the more commonly used features of JNDI.
An application that wants to access a printer needs the corresponding printer object. This is simply done as follows:
prt = (Printer) building7.lookup("puffin");
prt.print(document);
JNDI does all the work of locating the information needed to construct the printer object.
An application that wants to find a person's phone numbers, which are stored in the organization's directory, can simply do:
String[] attrs = {"workPhone", "cellPhone", "faxNumber"};
bobsPhones = directory.getAttributes("cn=Bob, o=Widget, c=US", attrs);
If there may be several Bobs in the Widget organization, the application can search the organization's directory to find the right Bob as follows:
bob = directory.search("o=Widget, c=US", "(cn=Bob)", searchctls);
This document describes the architecture and interfaces of JNDI.
