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本文主要研究一下LettucePoolingConnectionProvider
LettucePoolingConnectionProvider
spring-data-redis-2.0.10.RELEASE-sources.jar!/org/springframework/data/redis/connection/lettuce/LettucePoolingConnectionProvider.java
/**
* {@link LettuceConnectionProvider} with connection pooling support. This connection provider holds multiple pools (one
* per connection type) for contextualized connection allocation.
* <p />
* Each allocated connection is tracked and to be returned into the pool which created the connection. Instances of this
* class require {@link #destroy() disposal} to de-allocate lingering connections that were not returned to the pool and
* to close the pools.
*
* @author Mark Paluch
* @author Christoph Strobl
* @since 2.0
* @see #getConnection(Class)
*/
class LettucePoolingConnectionProvider implements LettuceConnectionProvider, RedisClientProvider, DisposableBean {
private final static Log log = LogFactory.getLog(LettucePoolingConnectionProvider.class);
private final LettuceConnectionProvider connectionProvider;
private final GenericObjectPoolConfig poolConfig;
private final Map<StatefulConnection<?, ?>, GenericObjectPool<StatefulConnection<?, ?>>> poolRef = new ConcurrentHashMap<>(
32);
private final Map<Class<?>, GenericObjectPool<StatefulConnection<?, ?>>> pools = new ConcurrentHashMap<>(32);
LettucePoolingConnectionProvider(LettuceConnectionProvider connectionProvider,
LettucePoolingClientConfiguration clientConfiguration) {
Assert.notNull(connectionProvider, "ConnectionProvider must not be null!");
Assert.notNull(clientConfiguration, "ClientConfiguration must not be null!");
this.connectionProvider = connectionProvider;
this.poolConfig = clientConfiguration.getPoolConfig();
}
/*
* (non-Javadoc)
* @see org.springframework.data.redis.connection.lettuce.LettuceConnectionProvider#getConnection(java.lang.Class)
*/
@Override
public <T extends StatefulConnection<?, ?>> T getConnection(Class<T> connectionType) {
GenericObjectPool<StatefulConnection<?, ?>> pool = pools.computeIfAbsent(connectionType, poolType -> {
return ConnectionPoolSupport.createGenericObjectPool(() -> connectionProvider.getConnection(connectionType),
poolConfig, false);
});
try {
StatefulConnection<?, ?> connection = pool.borrowObject();
poolRef.put(connection, pool);
return connectionType.cast(connection);
} catch (Exception e) {
throw new PoolException("Could not get a resource from the pool", e);
}
}
/*
* (non-Javadoc)
* @see org.springframework.data.redis.connection.lettuce.RedisClientProvider#getRedisClient()
*/
@Override
public AbstractRedisClient getRedisClient() {
if (connectionProvider instanceof RedisClientProvider) {
return ((RedisClientProvider) connectionProvider).getRedisClient();
}
throw new IllegalStateException(
String.format("Underlying connection provider %s does not implement RedisClientProvider!",
connectionProvider.getClass().getName()));
}
/*
* (non-Javadoc)
* @see org.springframework.data.redis.connection.lettuce.LettuceConnectionProvider#release(io.lettuce.core.api.StatefulConnection)
*/
@Override
public void release(StatefulConnection<?, ?> connection) {
GenericObjectPool<StatefulConnection<?, ?>> pool = poolRef.remove(connection);
if (pool == null) {
throw new PoolException("Returned connection " + connection
+ " was either previously returned or does not belong to this connection provider");
}
pool.returnObject(connection);
}
/*
* (non-Javadoc)
* @see org.springframework.beans.factory.DisposableBean#destroy()
*/
@Override
public void destroy() throws Exception {
if (!poolRef.isEmpty()) {
log.warn("LettucePoolingConnectionProvider contains unreleased connections");
poolRef.forEach((connection, pool) -> pool.returnObject(connection));
poolRef.clear();
}
pools.forEach((type, pool) -> pool.close());
pools.clear();
}
}
- 这个provider与普通的连接不同，它区分了不同类型的连接池，因而pools是map结构的，而且还多了poolRef这个map来维护每个连接所在连接池
- pools主要是用于根据连接类型获取对应连接池，用于连接的借用场景，而poolRef主要是用于连接的归还场景
- 这里采用了ConcurrentHashMap的computeIfAbsent方法，对于key不存在的则触发创建并返回，对于key存在的则直接返回
小结
- lettuce 4.0版本引入了StatefulConnection，它会维护登录、事务、所选数据库，读写等状态
- StatefulConnection有几个类型，分别是StatefulRedisConnection(
StatefulRedisPubSubConnection、StatefulRedisMasterSlaveConnection)、StatefulRedisSentinelConnection、StatefulRedisClusterConnection - LettucePoolingConnectionProvider维护了多类型的连接的连接池，因而采用map的数据结构，不然单一类型的连接直接使用GenericObjectPool即可
