spring-security/samples/chat-jc/src/main/java/sample/config/EmbeddedRedisConfig.java

package sample.config;
/*
 * Copyright 2002-2014 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.
 */

import java.io.IOException;
import java.net.ServerSocket;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import redis.embedded.RedisServer;

/**
 * Runs an embedded Redis instance. This is only necessary since we do not want
 * users to have to setup a Redis instance. In a production environment, this
 * would not be used since a Redis Server would be setup.
 *
 * @author Rob Winch
 */
@Configuration
public class EmbeddedRedisConfig {

    @Bean
    public static RedisServerBean redisServer() {
        return new RedisServerBean();
    }

    /**
     * Implements BeanDefinitionRegistryPostProcessor to ensure this Bean
     * is initialized before any other Beans. Specifically, we want to ensure
     * that the Redis Server is started before RedisHttpSessionConfiguration
     * attempts to enable Keyspace notifications.
     */
    static class RedisServerBean implements InitializingBean, DisposableBean, BeanDefinitionRegistryPostProcessor, RedisConnectionProperties {
        private RedisServer redisServer;

        public void afterPropertiesSet() throws Exception {
            redisServer = new RedisServer(getPort());
            redisServer.start();
        }

        public void destroy() throws Exception {
            if(redisServer != null) {
                redisServer.stop();
            }
        }

        public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {}

        public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {}

        private Integer availablePort;

        public int getPort() throws IOException {
            if(availablePort == null) {
                ServerSocket socket = new ServerSocket(0);
                availablePort = socket.getLocalPort();
                socket.close();
            }
            return availablePort;
        }
    }
}