/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements. See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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.apache.logging.log4j.core.appender.db.jdbc;
  
  import java.sql.DriverManager;
  import java.sql.SQLException;
  import java.util.concurrent.TimeUnit;
  
  import org.apache.commons.dbcp2.ConnectionFactory;
  import org.apache.commons.dbcp2.DriverManagerConnectionFactory;
  import org.apache.commons.dbcp2.PoolableConnection;
  import org.apache.commons.dbcp2.PoolableConnectionFactory;
  import org.apache.commons.dbcp2.PoolingDriver;
  import org.apache.commons.pool2.ObjectPool;
  import org.apache.commons.pool2.impl.GenericObjectPool;
  import org.apache.logging.log4j.core.Core;
  import org.apache.logging.log4j.core.config.Property;
  import org.apache.logging.log4j.core.config.plugins.Plugin;
  import org.apache.logging.log4j.core.config.plugins.PluginBuilderFactory;
  
  /**
   * A {@link ConnectionSource} that uses a JDBC connection string, a user name, and a password to call
   * {@link DriverManager#getConnection(String, String, String)}. The connections are served from an
   * <a href="http://commons.apache.org/proper/commons-dbcp/">Apache Commons DBCP</a> pooling driver.
   */
  @Plugin(name = "PoolingDriver", category = Core.CATEGORY_NAME, elementType = "connectionSource", printObject = true)
  public final class PoolingDriverConnectionSource extends AbstractDriverManagerConnectionSource {
  
      /**
       * Builds PoolingDriverConnectionSource instances.
       *
       * @param <B>
       *            This builder type or a subclass.
       */
      public static class Builder<B extends Builder<B>> extends AbstractDriverManagerConnectionSource.Builder<B>
      implements org.apache.logging.log4j.core.util.Builder<PoolingDriverConnectionSource> {
  
          public static final String DEFAULT_POOL_NAME = "example";
          private String poolName = DEFAULT_POOL_NAME;
  
          @Override
          public PoolingDriverConnectionSource build() {
              try {
                  return new PoolingDriverConnectionSource(getDriverClassName(), getConnectionString(), getUserName(),
                          getPassword(), getProperties(), poolName);
              } catch (final SQLException e) {
                  getLogger().error("Exception constructing {} to '{}'", getClass(), getConnectionString(), e);
                  return null;
              }
          }
  
          public B setPoolName(final String poolName) {
              this.poolName = poolName;
              return asBuilder();
          }
      }
  
      public static final String URL_PREFIX = "jdbc:apache:commons:dbcp:";
  
      // This method is not named newBuilder() to make the compiler happy.
      @PluginBuilderFactory
      public static <B extends Builder<B>> B newPoolingDriverConnectionSourceBuilder() {
          return new Builder<B>().asBuilder();
      }
  
      private final String poolingDriverClassName = "org.apache.commons.dbcp2.PoolingDriver";
  
      private final String poolName;
  
      public PoolingDriverConnectionSource(final String driverClassName, final String connectionString,
              final char[] userName, final char[] password, final Property[] properties, final String poolName)
              throws SQLException {
          super(driverClassName, connectionString, URL_PREFIX + poolName, userName, password, properties);
          this.poolName = poolName;
          setupDriver(connectionString);
      }
  
      @Override
      public String getActualConnectionString() {
          // TODO Auto-generated method stub
          return super.getActualConnectionString();
      }
  
      private PoolingDriver getPoolingDriver() throws SQLException {
          final PoolingDriver driver = (PoolingDriver) DriverManager.getDriver(URL_PREFIX);
         if (driver == null) {
             getLogger().error("No JDBC driver for '{}'", URL_PREFIX);
         }
         return driver;
     }
 
     private void setupDriver(final String connectionString) throws SQLException {
         //
         // First, we'll create a ConnectionFactory that the
         // pool will use to create Connections.
         // We'll use the DriverManagerConnectionFactory,
         // using the connect string passed in the command line
         // arguments.
         //
         final ConnectionFactory connectionFactory = new DriverManagerConnectionFactory(connectionString, null);
 
         //
         // Next, we'll create the PoolableConnectionFactory, which wraps
         // the "real" Connections created by the ConnectionFactory with
         // the classes that implement the pooling functionality.
         //
         final PoolableConnectionFactory poolableConnectionFactory = new PoolableConnectionFactory(connectionFactory,
                 null);
 
         //
         // Now we'll need a ObjectPool that serves as the
         // actual pool of connections.
         //
         // We'll use a GenericObjectPool instance, although
         // any ObjectPool implementation will suffice.
         //
         @SuppressWarnings("resource")
         // This GenericObjectPool will be closed on shutown
         final ObjectPool<PoolableConnection> connectionPool = new GenericObjectPool<>(poolableConnectionFactory);
 
         // Set the factory's pool property to the owning pool
         poolableConnectionFactory.setPool(connectionPool);
 
         loadDriver(poolingDriverClassName);
         final PoolingDriver driver = getPoolingDriver();
         if (driver != null) {
             getLogger().debug("Registering DBCP pool '{}'", poolName);
             driver.registerPool(poolName, connectionPool);
         }
         //
         // Now we can just use the connect string "jdbc:apache:commons:dbcp:example"
         // to access our pool of Connections.
         //
     }
 
     @Override
     public boolean stop(long timeout, TimeUnit timeUnit) {
         try {
             final PoolingDriver driver = getPoolingDriver();
             if (driver != null) {
                 getLogger().debug("Closing DBCP pool '{}'", poolName);
                 driver.closePool(poolName);
             }
             return true;
         } catch (Exception e) {
             getLogger().error("Exception stopping connection source for '{}' → '{}'", getConnectionString(),
                     getActualConnectionString(), e);
             return false;
         }
     }
 }