Spring to implement Failover mechansim

<bean id="highAvailabilityBean" class="org.springframework.remoting.support.FailoverProxyFactoryBean">
  <property name="serviceInterface" value="com.x.MyInterface">  <property name="serviceBeans">   <list>   <!-- service beans are typically proxies to remote services  -->    <ref bean="primaryServiceProvider">    <ref bean="fallBackServiceProvider">   </ref>  </ref></list>
package org.springframework.remoting.support;import java.lang.reflect.InvocationTargetException;import java.util.Iterator;import java.util.List;import org.aopalliance.intercept.MethodInterceptor;import org.aopalliance.intercept.MethodInvocation;import org.springframework.aop.framework.ProxyFactory;import org.springframework.beans.factory.FactoryBean;import org.springframework.beans.factory.InitializingBean;import org.springframework.remoting.support.RemoteAccessor;/*** Factory bean for proxies to redundant services. Behaves like theproxied* service when used as bean reference, exposing the specified service* interface, but with transparent fail-over. All call to the proxy are* delegated to the first object in the list of service providers (@see* #setServiceProviders(List)). When this delegated call fails, thenext* provider in the list will be called, etc.** @author be324288**/public class FailoverProxyFactoryBean extends RemoteAccessor implementsMethodInterceptor,InitializingBean, FactoryBean {private Object serviceProxy;private List serviceProviders;/*** The list of (redundant) objects that implement the interfacespecified* with {@link RemoteAccessor#setServiceInterface(java.lang.Class)}** @return*/public List getServiceProviders() {return serviceProviders;}/*** @param serviceProviders*/public void setServiceProviders(List serviceProviders) {this.serviceProviders = serviceProviders;}public void afterPropertiesSet() throws Exception {if (getServiceInterface() == null) {throw new IllegalArgumentException("serviceInterface isrequired");}if (serviceProviders == null || serviceProviders.isEmpty()) {throw new IllegalArgumentException("serviceBeans isrequired");}for (Object o : serviceProviders) {if (!getServiceInterface().isInstance(o)) {throw new IllegalArgumentException(o.getClass()+ " does not implement the serviceInterface: "+getServiceInterface());}}this.serviceProxy =ProxyFactory.getProxy(getServiceInterface(), this);}public Object getObject() {return this.serviceProxy;}public Class getObjectType() {return getServiceInterface();}public boolean isSingleton() {return true;}public Object invoke(MethodInvocation mi) throws Throwable {Iterator iter = serviceProviders.iterator();while (iter.hasNext()) {Object bean = iter.next();try {returnbean.getClass().getMethod(mi.getMethod().getName(),(Class[])mi.getMethod().getParameterTypes()).invoke(bean,mi.getArguments());} catch (InvocationTargetException e) {// try next bean or throw exception if this is the lastbeanif (!iter.hasNext()) {throw e.getCause();}}}return null;}}