MyBatis actuator with an overview of the source code parsing

Tags (separated by spaces): Mybatis

Actuator overview

Wanted, like tomcat, Mybatis actuators also exist, but no less complex actuator tomcat.
Actuator provides query, modify, commit the transaction, roll back the transaction, clearing cache, FlashStatement interface.
An actuator corresponds to a SqlSession, created by Configuration.
Mybatis actuators using entrusting mode design, BaseExecutor, SimpleExecutor, ReuseExecutor, CachingExecutor its implementation class. CachingExecutor hold a delegate object is achieved by the implementation of its core functions.
CachingExecutor in BaseExecutor basis to achieve cache function.
In simple terms Executor to achieve the interaction with the database.

Source resolve

Let's look at the process of creation Executor of Mybatis

Mybatis creation process

Implementation process: openSessionFromDataSource is openSession () method inside of a child, Mybatis in the creation of SqlSession, new an Executor and put it in the DefaultSqlSession, we can also interpret it this way a SqlSession hold a Executor. And performing database connection pool where there is no association.

private SqlSession openSessionFromDataSource(ExecutorType execType, TransactionIsolationLevel level, boolean autoCommit) {
    Transaction tx = null;
    try {
      final Environment environment = configuration.getEnvironment();
      final TransactionFactory transactionFactory = getTransactionFactoryFromEnvironment(environment);
      tx = transactionFactory.newTransaction(environment.getDataSource(), level, autoCommit);
      final Executor executor = configuration.newExecutor(tx, execType);
      return new DefaultSqlSession(configuration, executor, autoCommit);
    } catch (Exception e) {
      closeTransaction(tx); // may have fetched a connection so lets call close()
      throw ExceptionFactory.wrapException("Error opening session.  Cause: " + e, e);
    } finally {
      ErrorContext.instance().reset();
    }
  }

newExecutor openSessionFromDataSource method code which is as follows:

  public Executor newExecutor(Transaction transaction, ExecutorType executorType) {
    executorType = executorType == null ? defaultExecutorType : executorType;
    executorType = executorType == null ? ExecutorType.SIMPLE : executorType;
    Executor executor;
    if (ExecutorType.BATCH == executorType) {
      executor = new BatchExecutor(this, transaction);
    } else if (ExecutorType.REUSE == executorType) {
      executor = new ReuseExecutor(this, transaction);
    } else {
      executor = new SimpleExecutor(this, transaction);
    }
    if (cacheEnabled) {
      executor = new CachingExecutor(executor);
    }
    executor = (Executor) interceptorChain.pluginAll(executor);
    return executor;
  }

newExecutor in the Configuration Method, according to the type of determination is to generate executorType BatchExecutor or ReuseExecutor, SimpleExecutord
, cacheEnabled indicates whether to enable two cache. There is CachingExecutor a delegate delegate object, there real implementation object, interceptorChain interceptor chain of responsibility, Executor done in pluginAll conversion method, the final executor is a proxy object.
PS: actuators, interceptor, the cache is the most important of the three parts Mybatis.

The following is a class diagram Mybatis actuator, it can be seen from the actuator's delegated mode.
FIG Mybatis performing class

MyBatis actuator with an overview of the source code parsing

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