jndi
Product: xTier™/LWC 2.3 Whitepaper: n/a	support@fitechlabs.com  Download  Buy
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Description
The 'jndi' service provides an "umbrella" API and uniform configuration for any native JNDI implementation. This service provides implementation for some well-known JNDI usage patterns. Note that the JNDI kernel service does not implement the JNDI SPI directly but rather provides a vendor-independent configuration and access API, as well as additional utility methods on top of Context APIs. This, among other things, greatly benefits code portability with the ability to redeploy code utilizing the 'jndi' service with different underlying JNDI implementations with no code changes.

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Configuration
Configuration of the service is specified in the xtier_jndi.xml xTier™ configuration file. This file follows the standard xTier™ service configuration pattern and is illustrated by the following complete example of these object definition:

1		<xtier-jndi>
2		<region name="examples">
3		<!--
4		Specifyes the authoritativeness of
5		the service requested.
6		-->
7		<authoritative>true</authoritative>
8
9		<!--
10		Batch size to use when returning data via
11		the service's protocol.
12		-->
13		<batchsize>50</batchsize>
14
15		<!--
16		DNS host and domain names to use for
17		the JNDI URL context.
18		-->
19		<dns-url>dns://somehost/wiz.com</dns-url>
20
21		<!-- Initial context factory. -->
22		<init-context-factory>
23		com.sun.jndi.rmi.registry.RegistryContextFactory
24		</init-context-factory>
25
26		<!--
27		Preferred language to use with the service.
28		-->
29		<language>en:de:ru</language>
30
31		<!-- List of object factories to use. -->
32		<obj-factories>
33		com.foo.someFactory:com.foo.anotherFactory
34		</obj-factories>
35
36		<!-- Information for the service provider to use. -->
37		<provider-url>rmi://localhost:1099</provider-url>
38
39		<!--
40		Specifyes how referrals encountered by the service
41		provider are to be processed.
42		-->
43		<referral>follow</referral>
44
45		<!--
46		Security level to use. Its value is one of the
47		following strings: "none", "simple", "strong".
48		-->
49		<authentication>simple</authentication>
50
51		<!--
52		Identity of the principal for authenticating the
53		caller to the service. The format of the principal
54		depends on the authentication scheme.
55		-->
56		<credentials>777</credentials>
57
58		<!-- Security protocol to use. -->
59		<protocol>ssl</protocol>
60
61		<!--
62		List of state factories to use.
63		-->
64		<factories>com.foo.stateFactory</factories>
65
66		<!--
67		List of package prefixes to use when loading
68		in URL context factories.
69		-->
70		<url-pkg-prefixes>com.foo</url-pkg-prefixes>
71		</region>
72		</xtier-jndi>

Formal specification for this configuration file can be found in the xtier_jndi.dtd DTD file in the ${XTIER_ROOT}/config/dtd folder. The following table provides explanations for the configuration elements:

authentication	Corresponds to Context.SECURITY_AUTHENTICATION.
authoritative	Corresponds to Context.AUTHORITATIVE.
batchsize	Corresponds to Context.BATCHSIZE.
credentials	Corresponds to Context.SECURITY_PRINCIPAL.
dns-url	Corresponds to Context.DNS_URL.
factories	Corresponds to Context.STATE_FACTORIES.
init-context-factory	Corresponds to Context.INITIAL_CONTEXT_FACTORY.
language	Corresponds to Context.LANGUAGE.
obj-factories	Corresponds to Context.OBJECT_FACTORIES.
protocol	Corresponds to Context.SECURITY_PROTOCOL.
provider-url	Corresponds to Context.PROVIDER_URL.
referral	Corresponds to Context.REFERRAL.
url-pkg-prefixes	Corresponds to Context.URL_PKG_PREFIXES.

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Examples
The usage of the 'jndi' service follows the standard pattern of using an xTier™ service: you need to obtain an instance of the xTier™ kernel that serves as a service registry. Once you have the xTier™ kernel you can get an instance of any service, in our case the 'jndi' service.

1		// Get the instance of xTier kernel.
2		XtierKernel xtier = XtierKernel.getInstance();
3
4		// Get the instance of 'jndi' service.
5		JndiService jndi = xtier.jndi();
6
7		InitialContext ctx = jndi.getInitialContext();
8
9		Hashtable env = ctx.getEnvironment();
10
11		// Print out the JNDI settings.
12		for (Enumeration enum = env.keys(); enum.hasMoreElements() == true;) {
13		Object key = enum.nextElement();
14
15		System.out.println(key + " = " + env.get(key));
16		}
17
18		try {
19		jndi.bindEx(JNDI_NAME, new RefObj(), true);
20
21		jndi.unbindEx(JNDI_NAME);
22		}
23		catch (NamingException e) {
24		// ...
25		}
26
27		// Stop the xTier kernel.
28		xtier.stop();

Note also that every utility method comes in four versions:

• Method that takes Context and JNDI name as a String
• Method that does not take Context and takes JNDI name as a String
• Method that takes Context and JNDI name as a Name
• Method that does not take Context and takes JNDI name as a Name

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