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154 lines
5.5 KiB
154 lines
5.5 KiB
/* |
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* Copyright 2002-2012 the original author or authors. |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* https://www.apache.org/licenses/LICENSE-2.0 |
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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package com.fr.third.springframework.ejb.access; |
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import com.fr.third.springframework.beans.factory.DisposableBean; |
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import org.aopalliance.intercept.MethodInvocation; |
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import javax.ejb.EJBObject; |
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import javax.naming.NamingException; |
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import java.lang.reflect.InvocationTargetException; |
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/** |
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* Basic invoker for a remote Stateless Session Bean. |
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* Designed for EJB 2.x, but works for EJB 3 Session Beans as well. |
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* |
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* <p>"Creates" a new EJB instance for each invocation, or caches the session |
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* bean instance for all invocations (see {@link #setCacheSessionBean}). |
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* See {@link com.fr.third.springframework.jndi.JndiObjectLocator} for info on |
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* how to specify the JNDI location of the target EJB. |
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* |
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* <p>In a bean container, this class is normally best used as a singleton. However, |
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* if that bean container pre-instantiates singletons (as do the XML ApplicationContext |
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* variants) you may have a problem if the bean container is loaded before the EJB |
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* container loads the target EJB. That is because by default the JNDI lookup will be |
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* performed in the init method of this class and cached, but the EJB will not have been |
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* bound at the target location yet. The best solution is to set the "lookupHomeOnStartup" |
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* property to "false", in which case the home will be fetched on first access to the EJB. |
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* (This flag is only true by default for backwards compatibility reasons). |
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* |
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* <p>This invoker is typically used with an RMI business interface, which serves |
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* as super-interface of the EJB component interface. Alternatively, this invoker |
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* can also proxy a remote SLSB with a matching non-RMI business interface, i.e. an |
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* interface that mirrors the EJB business methods but does not declare RemoteExceptions. |
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* In the latter case, RemoteExceptions thrown by the EJB stub will automatically get |
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* converted to Spring's unchecked RemoteAccessException. |
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* |
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* @author Rod Johnson |
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* @author Juergen Hoeller |
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* @since 09.05.2003 |
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* @see com.fr.third.springframework.remoting.RemoteAccessException |
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* @see AbstractSlsbInvokerInterceptor#setLookupHomeOnStartup |
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* @see AbstractSlsbInvokerInterceptor#setCacheHome |
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* @see AbstractRemoteSlsbInvokerInterceptor#setRefreshHomeOnConnectFailure |
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*/ |
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public class SimpleRemoteSlsbInvokerInterceptor extends AbstractRemoteSlsbInvokerInterceptor |
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implements DisposableBean { |
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private boolean cacheSessionBean = false; |
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private Object beanInstance; |
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private final Object beanInstanceMonitor = new Object(); |
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/** |
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* Set whether to cache the actual session bean object. |
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* <p>Off by default for standard EJB compliance. Turn this flag |
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* on to optimize session bean access for servers that are |
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* known to allow for caching the actual session bean object. |
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* @see #setCacheHome |
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*/ |
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public void setCacheSessionBean(boolean cacheSessionBean) { |
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this.cacheSessionBean = cacheSessionBean; |
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} |
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/** |
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* This implementation "creates" a new EJB instance for each invocation. |
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* Can be overridden for custom invocation strategies. |
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* <p>Alternatively, override {@link #getSessionBeanInstance} and |
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* {@link #releaseSessionBeanInstance} to change EJB instance creation, |
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* for example to hold a single shared EJB component instance. |
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*/ |
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@Override |
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protected Object doInvoke(MethodInvocation invocation) throws Throwable { |
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throw new UnsupportedOperationException(); |
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} |
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/** |
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* Return an EJB component instance to delegate the call to. |
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* <p>The default implementation delegates to {@link #newSessionBeanInstance}. |
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* @return the EJB component instance |
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* @throws NamingException if thrown by JNDI |
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* @throws InvocationTargetException if thrown by the create method |
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* @see #newSessionBeanInstance |
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*/ |
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protected Object getSessionBeanInstance() throws NamingException, InvocationTargetException { |
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if (this.cacheSessionBean) { |
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synchronized (this.beanInstanceMonitor) { |
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if (this.beanInstance == null) { |
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this.beanInstance = newSessionBeanInstance(); |
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} |
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return this.beanInstance; |
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} |
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} |
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else { |
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return newSessionBeanInstance(); |
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} |
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} |
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/** |
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* Release the given EJB instance. |
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* <p>The default implementation delegates to {@link #removeSessionBeanInstance}. |
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* @param ejb the EJB component instance to release |
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* @see #removeSessionBeanInstance |
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*/ |
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protected void releaseSessionBeanInstance(EJBObject ejb) { |
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if (!this.cacheSessionBean) { |
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removeSessionBeanInstance(ejb); |
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} |
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} |
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/** |
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* Reset the cached session bean instance, if necessary. |
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*/ |
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@Override |
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protected void refreshHome() throws NamingException { |
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super.refreshHome(); |
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if (this.cacheSessionBean) { |
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synchronized (this.beanInstanceMonitor) { |
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this.beanInstance = null; |
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} |
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} |
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} |
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/** |
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* Remove the cached session bean instance, if necessary. |
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*/ |
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@Override |
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public void destroy() { |
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if (this.cacheSessionBean) { |
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synchronized (this.beanInstanceMonitor) { |
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if (this.beanInstance instanceof EJBObject) { |
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removeSessionBeanInstance((EJBObject) this.beanInstance); |
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} |
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} |
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} |
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} |
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}
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