/*
* Copyright 2002-2009 the original author or authors.
*
* Licensed 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.springframework.jndi;
import java.util.Hashtable;
import java.util.Properties;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NameNotFoundException;
import javax.naming.NamingException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.util.CollectionUtils;
/**
* 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.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @see JndiCallback
* @see #execute
*/
public class JndiTemplate {
protected final Log logger = LogFactory.getLog(getClass());
private Properties environment;
/**
* Create a new JndiTemplate instance.
*/
public JndiTemplate() {
}
/**
* Create a new JndiTemplate instance, using the given environment.
*/
public JndiTemplate(Properties environment) {
this.environment = environment;
}
/**
* Set the environment for the JNDI InitialContext.
*/
public void setEnvironment(Properties environment) {
this.environment = environment;
}
/**
* Return the environment for the JNDI InitialContext, if any.
*/
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 <T> T execute(JndiCallback<T> contextCallback) throws NamingException {
Context ctx = getContext();
try {
return contextCallback.doInContext(ctx);
}
finally {
releaseContext(ctx);
}
}
/**
* Obtain a JNDI context corresponding to this template's configuration.
* Called by {@link #execute}; may also be called directly.
* <p>The default implementation delegates to {@link #createInitialContext()}.
* @return the JNDI context (never <code>null</code>)
* @throws NamingException if context retrieval failed
* @see #releaseContext
*/
public Context getContext() throws NamingException {
return createInitialContext();
}
/**
* Release a JNDI context as obtained from {@link #getContext()}.
* @param ctx the JNDI context to release (may be <code>null</code>)
* @see #getContext
*/
public void releaseContext(Context ctx) {
if (ctx != null) {
try {
ctx.close();
}
catch (NamingException ex) {
logger.debug("Could not close JNDI InitialContext", ex);
}
}
}
/**
* Create a new JNDI initial context. Invoked by {@link #getContext}.
* <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
*/
protected Context createInitialContext() throws NamingException {
Hashtable icEnv = null;
Properties env = getEnvironment();
if (env != null) {
icEnv = new Hashtable(env.size());
CollectionUtils.mergePropertiesIntoMap(env, icEnv);
}
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 (logger.isDebugEnabled()) {
logger.debug("Looking up JNDI object with name [" + name + "]");
}
return execute(new JndiCallback<Object>() {
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
*/
@SuppressWarnings("unchecked")
public <T> T lookup(String name, Class<T> requiredType) throws NamingException {
Object jndiObject = lookup(name);
if (requiredType != null && !requiredType.isInstance(jndiObject)) {
throw new TypeMismatchNamingException(
name, requiredType, (jndiObject != null ? jndiObject.getClass() : null));
}
return (T) 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 (logger.isDebugEnabled()) {
logger.debug("Binding JNDI object with name [" + name + "]");
}
execute(new JndiCallback<Object>() {
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 (logger.isDebugEnabled()) {
logger.debug("Rebinding JNDI object with name [" + name + "]");
}
execute(new JndiCallback<Object>() {
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 (logger.isDebugEnabled()) {
logger.debug("Unbinding JNDI object with name [" + name + "]");
}
execute(new JndiCallback<Object>() {
public Object doInContext(Context ctx) throws NamingException {
ctx.unbind(name);
return null;
}
});
}
}
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