SpringManagedTransaction.java

/**
 *    Copyright 2010-2015 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.
 */
package org.mybatis.spring.transaction;

import static org.springframework.util.Assert.notNull;

import java.sql.Connection;
import java.sql.SQLException;

import javax.sql.DataSource;

import org.apache.ibatis.logging.Log;
import org.apache.ibatis.logging.LogFactory;
import org.apache.ibatis.transaction.Transaction;
import org.springframework.jdbc.datasource.DataSourceUtils;

/**
 * {@code SpringManagedTransaction} handles the lifecycle of a JDBC connection.
 * It retrieves a connection from Spring's transaction manager and returns it back to it
 * when it is no longer needed.
 * <p>
 * If Spring's transaction handling is active it will no-op all commit/rollback/close calls
 * assuming that the Spring transaction manager will do the job.
 * <p>
 * If it is not it will behave like {@code JdbcTransaction}.
 *
 * @author Hunter Presnall
 * @author Eduardo Macarron
 * 
 * @version $Id$
 */
public class SpringManagedTransaction implements Transaction {

  private static final Log LOGGER = LogFactory.getLog(SpringManagedTransaction.class);

  private final DataSource dataSource;

  private Connection connection;

  private boolean isConnectionTransactional;

  private boolean autoCommit;

  public SpringManagedTransaction(DataSource dataSource) {
    notNull(dataSource, "No DataSource specified");
    this.dataSource = dataSource;
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public Connection getConnection() throws SQLException {
    if (this.connection == null) {
      openConnection();
    }
    return this.connection;
  }

  /**
   * Gets a connection from Spring transaction manager and discovers if this
   * {@code Transaction} should manage connection or let it to Spring.
   * <p>
   * It also reads autocommit setting because when using Spring Transaction MyBatis
   * thinks that autocommit is always false and will always call commit/rollback
   * so we need to no-op that calls.
   */
  private void openConnection() throws SQLException {
    this.connection = DataSourceUtils.getConnection(this.dataSource);
    this.autoCommit = this.connection.getAutoCommit();
    this.isConnectionTransactional = DataSourceUtils.isConnectionTransactional(this.connection, this.dataSource);

    if (LOGGER.isDebugEnabled()) {
      LOGGER.debug(
          "JDBC Connection ["
              + this.connection
              + "] will"
              + (this.isConnectionTransactional ? " " : " not ")
              + "be managed by Spring");
    }
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public void commit() throws SQLException {
    if (this.connection != null && !this.isConnectionTransactional && !this.autoCommit) {
      if (LOGGER.isDebugEnabled()) {
        LOGGER.debug("Committing JDBC Connection [" + this.connection + "]");
      }
      this.connection.commit();
    }
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public void rollback() throws SQLException {
    if (this.connection != null && !this.isConnectionTransactional && !this.autoCommit) {
      if (LOGGER.isDebugEnabled()) {
        LOGGER.debug("Rolling back JDBC Connection [" + this.connection + "]");
      }
      this.connection.rollback();
    }
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public void close() throws SQLException {
    DataSourceUtils.releaseConnection(this.connection, this.dataSource);
  }

}