| author | ohair |
| Wed, 26 May 2010 20:28:04 -0700 | |
| changeset 5551 | 327690766109 |
| parent 5506 | 202f599c92aa |
| child 23712 | d46a902c1aed |
| permissions | -rw-r--r-- |
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> |
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Copyright (c) 1999, 2006, Oracle and/or its affiliates. All rights reserved. |
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DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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This code is free software; you can redistribute it and/or modify it |
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under the terms of the GNU General Public License version 2 only, as |
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published by the Free Software Foundation. Oracle designates this |
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particular file as subject to the "Classpath" exception as provided |
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by Oracle in the LICENSE file that accompanied this code. |
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This code is distributed in the hope that it will be useful, but WITHOUT |
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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version 2 for more details (a copy is included in the LICENSE file that |
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accompanied this code). |
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You should have received a copy of the GNU General Public License version |
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2 along with this work; if not, write to the Free Software Foundation, |
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Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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327690766109
6956202: Fix a few missed rebranding issues, please contact lines etc.
ohair
parents:
5506
diff
changeset
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Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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327690766109
6956202: Fix a few missed rebranding issues, please contact lines etc.
ohair
parents:
5506
diff
changeset
|
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or visit www.oracle.com if you need additional information or have any |
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327690766109
6956202: Fix a few missed rebranding issues, please contact lines etc.
ohair
parents:
5506
diff
changeset
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questions. |
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--> |
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</head> |
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<body bgcolor="white"> |
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Provides the classes and interfaces for accessing naming services. |
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<p> |
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This package defines the naming operations of the Java Naming and |
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Directory Interface<font size=-2><sup>TM</sup></font> (JNDI). |
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JNDI provides naming and directory functionality to applications |
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written in the Java programming language. It is designed to be |
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independent of any specific naming or directory service |
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implementation. Thus a variety of services--new, emerging, and |
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already deployed ones--can be accessed in a common way. |
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<h4>Context</h4> |
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<p> |
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This package defines the notion of a <em>context</em>, represented |
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by the <tt>Context</tt> interface. |
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A context consists of a set of name-to-object <em>bindings</em>. |
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<tt>Context</tt> is the core interface for looking up, binding, unbinding, |
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and renaming objects, and for creating and destroying subcontexts. |
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<p> |
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<tt>lookup()</tt> is the most commonly used operation. |
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You supply <tt>lookup()</tt> |
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the name of the object you want |
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to look up, and it returns the object bound to that name. |
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For example, the following code fragment looks up |
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a printer and sends a document to the printer object |
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to be printed: |
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<blockquote> |
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<pre> |
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Printer printer = (Printer)ctx.lookup("treekiller");
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printer.print(report); |
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</pre> |
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</blockquote> |
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<h4>Names</h4> |
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<p> |
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Every naming method in the <tt>Context</tt> |
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interface has two |
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overloads: one that accepts a |
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<tt>Name</tt> argument and one that accepts a string name. |
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<tt>Name</tt> is an interface that represents a generic |
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name--an ordered sequence of zero of more components. |
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For these methods, <tt>Name</tt> can be used to represent a |
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<em>composite name</em> (<tt>CompositeName</tt>) |
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so that you can name an object using a name which spans multiple namespaces. |
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<p> |
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The overloads that accept <tt>Name</tt> |
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are useful for applications that need to manipulate names: composing |
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them, comparing components, and so on. |
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The overloads that accept string names are likely to be more useful |
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for simple applications, such as those that simply read in a name |
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and look up the corresponding object. |
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<p> |
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<h4>Bindings</h4> |
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The <tt>Binding</tt> class represents a name-to-object binding. |
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It is a tuple containing the name of the bound object, |
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the name of the object's class, and the object itself. |
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<p> |
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The <tt>Binding</tt> class is actually a subclass of |
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<tt>NameClassPair</tt>, which consists |
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simply of the object's name and the object's class name. |
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The <tt>NameClassPair</tt> is useful when you only want |
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information about the object's class and do not want to |
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pay the extra cost of getting the object. |
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<h4>References</h4> |
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Objects are stored in naming and directory services in different ways. |
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If an object store supports storing Java objects, |
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it might support storing an object in its serialized form. |
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However, some naming and directory services do not support the |
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storing of Java objects. Furthermore, for some |
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objects in the directory, Java programs are but one group of applications |
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that access them. In this case, a serialized Java object might |
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not be the most appropriate representation. |
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JNDI defines a <em>reference</em>, represented by the <tt>Reference</tt> |
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class, which contains information on how to construct a copy of the object. |
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JNDI will attempt to turn references looked up from the directory |
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into the Java objects they represent, so that |
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JNDI clients have the illusion that what |
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is stored in the directory are Java objects. |
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<h4>The Initial Context</h4> |
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In JNDI, all naming and directory operations are performed relative |
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to a context. There are no absolute roots. |
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Therefore JNDI defines an <em>initial context</em>, |
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<tt>InitialContext</tt>, |
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which provides a starting point for naming and directory operations. |
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Once you have an initial context, you can use it to |
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look up other contexts and objects. |
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<h4>Exceptions</h4> |
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JNDI defines a class hierarchy for exceptions that can be thrown in |
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the course of performing naming and directory operations. The root of |
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this class hierarchy is <tt>NamingException</tt>. |
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Programs interested in dealing with a particular exception |
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can catch the corresponding subclass of the exception. |
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Otherwise, programs should catch <tt>NamingException</tt>. |
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<h2>Package Specification</h2> |
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The JNDI API Specification and related documents can be found in the |
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<a href="../../../technotes/guides/jndi/index.html">JNDI documentation</a>. |
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@since 1.3 |
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</body> |
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</html> |