97 lines
2.6 KiB
HTML
97 lines
2.6 KiB
HTML
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html>
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<head>
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<META http-equiv="Content-Type" content="text/html; charset=utf-8">
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<LINK rel="stylesheet" type="text/css" href="../../../rzahg/ic.css">
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<title>JNDI coding examples</title>
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</head>
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<BODY>
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<!-- Java sync-link -->
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<SCRIPT LANGUAGE="Javascript" SRC="../../../rzahg/synch.js" TYPE="text/javascript"></SCRIPT>
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<h6><a name="jndicchx"></a>JNDI coding examples</h6>
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<p>This Java code snippet demonstrates several techniques for controlling JNDI cache behavior, discussed in <a href="jndicchp.htm">JNDI cache properties</a>. Note that the caching discussed in this section pertains only to the WebSphere Application Server - Express implementation of the initial context factory. Assume that the property, java.naming.factory.initial, is set to "com.ibm.ejs.ns.WsnInitialContextFactory" as a java.lang.System property.</p>
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<pre>
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import java.util.Hashtable;
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import javax.naming.InitialContext;
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import javax.naming.Context;
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import com.ibm.websphere.naming.PROPS;
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// ... class declaration, method declaration code here ...
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Hashtable env;
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Context ctx;
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// To clear a cache:
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// ...class declaration, method declaration code here...
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try {
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env = new Hashtable();
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env.put(PROPS.JNDI_CACHE_OBJECT, PROPS.JNDI_CACHE_OBJECT_CLEARED);
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ctx = new InitialContext(env);
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}
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catch(javax.naming.NamingException e) {
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// error-handling code
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}
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// To set a cache's maximum cache lifetime to 60 minutes:
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try {
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env = new Hashtable();
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env.put(PROPS.JNDI_CACHE_MAX_LIFE, "60");
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ctx = new InitialContext(env);
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}
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catch(javax.naming.NamingException e) {
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// error-handling code
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}
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// To turn caching off:
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try {
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env = new Hashtable();
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env.put(PROPS.JNDI_CACHE_OBJECT, PROPS.JNDI_CACHE_OBJECT_NONE);
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ctx = new InitialContext(env);
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}
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catch(javax.naming.NamingException e) {
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// error-handling code
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}
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// To use caching and no caching:
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try {
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env = new Hashtable();
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env.put(PROPS.JNDI_CACHE_OBJECT, PROPS.JNDI_CACHE_OBJECT_POPULATED);
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ctx = new InitialContext(env);
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env.put(PROPS.JNDI_CACHE_OBJECT, PROPS.JNDI_CACHE_OBJECT_NONE);
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Context noCacheCtx = new InitialContext(env);
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}
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catch(javax.naming.NamingException e) {
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// error-handling code
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}
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try {
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Object o;
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// Use caching to look up the datasource, since it should rarely change.
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o = ctx.lookup("java:comp/env/jdbc/MyDataSource");
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// Narrow, etc. ...
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// Do not use cache if data is volatile.
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o = noCacheCtx.lookup("com/mycom/VolatileObject");
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// ...
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}
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catch(javax.naming.NamingException e) {
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// error-handling code
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}
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</pre>
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</body>
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</html>
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