org.springframework.jndi.JndiObjectTargetSource Maven / Gradle / Ivy
/*
* Copyright 2002-2017 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 javax.naming.NamingException;
import org.springframework.aop.TargetSource;
import org.springframework.lang.Nullable;
/**
* AOP {@link org.springframework.aop.TargetSource} that provides
* configurable JNDI lookups for {@code getTarget()} calls.
*
* Can be used as alternative to {@link JndiObjectFactoryBean}, to allow for
* relocating a JNDI object lazily or for each operation (see "lookupOnStartup"
* and "cache" properties). This is particularly useful during development, as it
* allows for hot restarting of the JNDI server (for example, a remote JMS server).
*
*
Example:
*
*
* <bean id="queueConnectionFactoryTarget" class="org.springframework.jndi.JndiObjectTargetSource">
* <property name="jndiName" value="JmsQueueConnectionFactory"/>
* <property name="lookupOnStartup" value="false"/>
* </bean>
*
* <bean id="queueConnectionFactory" class="org.springframework.aop.framework.ProxyFactoryBean">
* <property name="proxyInterfaces" value="javax.jms.QueueConnectionFactory"/>
* <property name="targetSource" ref="queueConnectionFactoryTarget"/>
* </bean>
*
* A {@code createQueueConnection} call on the "queueConnectionFactory" proxy will
* cause a lazy JNDI lookup for "JmsQueueConnectionFactory" and a subsequent delegating
* call to the retrieved QueueConnectionFactory's {@code createQueueConnection}.
*
* Alternatively, use a {@link JndiObjectFactoryBean} with a "proxyInterface".
* "lookupOnStartup" and "cache" can then be specified on the JndiObjectFactoryBean,
* creating a JndiObjectTargetSource underneath (instead of defining separate
* ProxyFactoryBean and JndiObjectTargetSource beans).
*
* @author Juergen Hoeller
* @since 1.1
* @see #setLookupOnStartup
* @see #setCache
* @see org.springframework.aop.framework.ProxyFactoryBean#setTargetSource
* @see JndiObjectFactoryBean#setProxyInterface
*/
public class JndiObjectTargetSource extends JndiObjectLocator implements TargetSource {
private boolean lookupOnStartup = true;
private boolean cache = true;
@Nullable
private Object cachedObject;
@Nullable
private Class targetClass;
/**
* Set whether to look up the JNDI object on startup. Default is "true".
*
Can be turned off to allow for late availability of the JNDI object.
* In this case, the JNDI object will be fetched on first access.
* @see #setCache
*/
public void setLookupOnStartup(boolean lookupOnStartup) {
this.lookupOnStartup = lookupOnStartup;
}
/**
* Set whether to cache the JNDI object once it has been located.
* Default is "true".
*
Can be turned off to allow for hot redeployment of JNDI objects.
* In this case, the JNDI object will be fetched for each invocation.
* @see #setLookupOnStartup
*/
public void setCache(boolean cache) {
this.cache = cache;
}
@Override
public void afterPropertiesSet() throws NamingException {
super.afterPropertiesSet();
if (this.lookupOnStartup) {
Object object = lookup();
if (this.cache) {
this.cachedObject = object;
}
else {
this.targetClass = object.getClass();
}
}
}
@Override
@Nullable
public Class getTargetClass() {
if (this.cachedObject != null) {
return this.cachedObject.getClass();
}
else if (this.targetClass != null) {
return this.targetClass;
}
else {
return getExpectedType();
}
}
@Override
public boolean isStatic() {
return (this.cachedObject != null);
}
@Override
@Nullable
public Object getTarget() {
try {
if (this.lookupOnStartup || !this.cache) {
return (this.cachedObject != null ? this.cachedObject : lookup());
}
else {
synchronized (this) {
if (this.cachedObject == null) {
this.cachedObject = lookup();
}
return this.cachedObject;
}
}
}
catch (NamingException ex) {
throw new JndiLookupFailureException("JndiObjectTargetSource failed to obtain new target object", ex);
}
}
@Override
public void releaseTarget(Object target) {
}
}