Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ package org.jsecurity.jndi; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import javax.naming.Context; import javax.naming.InitialContext; import javax.naming.NameNotFoundException; import javax.naming.NamingException; import java.util.Enumeration; import java.util.Hashtable; import java.util.Properties; /** * Helper class that simplifies JNDI operations. It provides methods to lookup and * bind objects, and allows implementations of the {@link JndiCallback} interface * to perform any operation they like with a JNDI naming context provided. * * <p>Note that this implementation is an almost exact copy of the Spring Framework's identically named class from * their 2.5.4 distribution - we didn't want to re-invent the wheel, but not require a full dependency on the * Spring framework, nor does Spring make available only its JNDI classes in a small jar, or we would have used that. * Since JSecurity is also Apache 2.0 licensed, all regular licenses and conditions and authors have remained in tact. * * @author Rod Johnson * @author Juergen Hoeller * @see JndiCallback * @see #execute */ public class JndiTemplate { private static final Log log = LogFactory.getLog(JndiTemplate.class); private Properties environment; /** * Create a new JndiTemplate instance. */ public JndiTemplate() { } /** * Create a new JndiTemplate instance, using the given environment. * * @param environment the Properties to initialize with */ public JndiTemplate(Properties environment) { this.environment = environment; } /** * Set the environment for the JNDI InitialContext. * * @param environment the Properties to initialize with */ public void setEnvironment(Properties environment) { this.environment = environment; } /** * Return the environment for the JNDI InitialContext, or <code>null</code> if none should be used. * * @return the environment for the JNDI InitialContext, or <code>null</code> if none should be used. */ public Properties getEnvironment() { return this.environment; } /** * Execute the given JNDI context callback implementation. * * @param contextCallback JndiCallback implementation * @return a result object returned by the callback, or <code>null</code> * @throws NamingException thrown by the callback implementation * @see #createInitialContext */ public Object execute(JndiCallback contextCallback) throws NamingException { Context ctx = createInitialContext(); try { return contextCallback.doInContext(ctx); } finally { try { ctx.close(); } catch (NamingException ex) { log.debug("Could not close JNDI InitialContext", ex); } } } /** * Create a new JNDI initial context. Invoked by {@link #execute}. * <p>The default implementation use this template's environment settings. * Can be subclassed for custom contexts, e.g. for testing. * * @return the initial Context instance * @throws NamingException in case of initialization errors */ @SuppressWarnings({ "unchecked" }) protected Context createInitialContext() throws NamingException { Properties env = getEnvironment(); Hashtable icEnv = null; if (env != null) { icEnv = new Hashtable(env.size()); for (Enumeration en = env.propertyNames(); en.hasMoreElements();) { String key = (String) en.nextElement(); icEnv.put(key, env.getProperty(key)); } } return new InitialContext(icEnv); } /** * Look up the object with the given name in the current JNDI context. * * @param name the JNDI name of the object * @return object found (cannot be <code>null</code>; if a not so well-behaved * JNDI implementations returns null, a NamingException gets thrown) * @throws NamingException if there is no object with the given * name bound to JNDI */ public Object lookup(final String name) throws NamingException { if (log.isDebugEnabled()) { log.debug("Looking up JNDI object with name [" + name + "]"); } return execute(new JndiCallback() { public Object doInContext(Context ctx) throws NamingException { Object located = ctx.lookup(name); if (located == null) { throw new NameNotFoundException( "JNDI object with [" + name + "] not found: JNDI implementation returned null"); } return located; } }); } /** * Look up the object with the given name in the current JNDI context. * * @param name the JNDI name of the object * @param requiredType type the JNDI object must match. Can be an interface or * superclass of the actual class, or <code>null</code> for any match. For example, * if the value is <code>Object.class</code>, this method will succeed whatever * the class of the returned instance. * @return object found (cannot be <code>null</code>; if a not so well-behaved * JNDI implementations returns null, a NamingException gets thrown) * @throws NamingException if there is no object with the given * name bound to JNDI */ public Object lookup(String name, Class requiredType) throws NamingException { Object jndiObject = lookup(name); if (requiredType != null && !requiredType.isInstance(jndiObject)) { String msg = "Jndi object acquired under name '" + name + "' is of type [" + jndiObject.getClass().getName() + "] and not assignable to the required type [" + requiredType.getName() + "]."; throw new NamingException(msg); } return jndiObject; } /** * Bind the given object to the current JNDI context, using the given name. * * @param name the JNDI name of the object * @param object the object to bind * @throws NamingException thrown by JNDI, mostly name already bound */ public void bind(final String name, final Object object) throws NamingException { if (log.isDebugEnabled()) { log.debug("Binding JNDI object with name [" + name + "]"); } execute(new JndiCallback() { public Object doInContext(Context ctx) throws NamingException { ctx.bind(name, object); return null; } }); } /** * Rebind the given object to the current JNDI context, using the given name. * Overwrites any existing binding. * * @param name the JNDI name of the object * @param object the object to rebind * @throws NamingException thrown by JNDI */ public void rebind(final String name, final Object object) throws NamingException { if (log.isDebugEnabled()) { log.debug("Rebinding JNDI object with name [" + name + "]"); } execute(new JndiCallback() { public Object doInContext(Context ctx) throws NamingException { ctx.rebind(name, object); return null; } }); } /** * Remove the binding for the given name from the current JNDI context. * * @param name the JNDI name of the object * @throws NamingException thrown by JNDI, mostly name not found */ public void unbind(final String name) throws NamingException { if (log.isDebugEnabled()) { log.debug("Unbinding JNDI object with name [" + name + "]"); } execute(new JndiCallback() { public Object doInContext(Context ctx) throws NamingException { ctx.unbind(name); return null; } }); } }