src/org/objectweb/cjdbc/controller/connection/AbstractPoolConnectionManager.java

説明を見る。

package org.objectweb.cjdbc.controller.connection;

import java.io.Serializable;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Stack;
import java.util.Vector;

import org.objectweb.cjdbc.common.i18n.Translate;

public abstract class AbstractPoolConnectionManager
    extends
      AbstractConnectionManager implements Serializable
{
  /*
   * How the code is organized ? 1. Member variables 2. Constructor(s) 3.
   * Connection handling 4. Getter/Setter (possibly in alphabetical order)
   */

  protected transient Stack  freeConnections;

  protected transient Vector activeConnections;

  protected int              poolSize;

  /*
   * Constructor(s)
   */

  public AbstractPoolConnectionManager(String backendUrl, String backendName,
      String login, String password, String driverPath, String driverClassName,
      int poolSize)
  {
    super(backendUrl, backendName, login, password, driverPath, driverClassName);

    if (poolSize < 1)
      throw new IllegalArgumentException(
          "Illegal value for size of the pool connection manager: " + poolSize);

    this.poolSize = poolSize;
    this.freeConnections = new Stack();
    this.activeConnections = new Vector(poolSize);
    this.initialized = false;

    if (logger.isDebugEnabled())
      logger.debug(Translate.get("connection.backend.pool.created",
          new String[]{backendName, String.valueOf(poolSize)}));
  }

  /*
   * Connection handling
   */

  public synchronized void initializeConnections() throws SQLException
  {
    initializeConnections(poolSize);
  }

  public synchronized void initializeConnections(int initPoolSize)
      throws SQLException
  {
    if (initialized)
      throw new SQLException("Connection pool for backend '" + backendUrl
          + "' already initialized");

    if (initPoolSize > poolSize)
    {
      logger.warn(Translate.get("connection.max.poolsize.reached",
          new String[]{String.valueOf(initPoolSize), String.valueOf(poolSize),
              String.valueOf(poolSize)}));
      initPoolSize = poolSize;
    }

    Connection c = null;

    boolean connectionsAvailable = true;
    int i = 0;
    while ((i < initPoolSize) && connectionsAvailable)
    {
      c = getConnectionFromDriver();

      if (c == null)
        connectionsAvailable = false;

      if (!connectionsAvailable)
      {
        if (i > 0)
        {
          logger.warn(Translate.get("connection.limit.poolsize", i));
        }
        else
        {
          logger.warn(Translate.get("connection.initialize.pool.failed"));
          poolSize = 0;
        }
      }
      else
      {
        freeConnections.push(c);
        i++;
      }
    }

    poolSize = i;
    initialized = true;

    if (poolSize == 0) // Should never happen
      logger.error(Translate.get("connection.empty.pool"));
    if (logger.isDebugEnabled())
      logger.debug(Translate.get("connection.pool.initialized", new String[]{
          String.valueOf(initPoolSize), backendUrl}));

  }

  public synchronized void finalizeConnections() throws SQLException
  {
    if (!initialized)
    {
      String msg = Translate.get("connection.pool.not.initialized");
      logger.error(msg);
      throw new SQLException(msg);
    }

    Connection c;
    boolean error = false;

    // Close free connections
    initialized = false;
    int freed = 0;
    while (!freeConnections.isEmpty())
    {
      c = (Connection) freeConnections.pop();
      try
      {
        c.close();
      }
      catch (SQLException e)
      {
        error = true;
      }
      freed++;
    }
    if (logger.isInfoEnabled())
      logger.info(Translate.get("connection.freed.connection", new String[]{
          String.valueOf(freed), backendUrl}));

    // Close active connections
    int size = activeConnections.size();
    if (size > 0)
    {
      logger.warn(Translate.get("connection.connections.still.active", size));
      for (int i = 0; i < size; i++)
      {
        c = (Connection) activeConnections.get(i);
        try
        {
          c.close();
        }
        catch (SQLException e)
        {
          error = true;
        }
      }
    }

    // Clear connections to ensure that the eventually not closed connections
    // will be closed when the objects will be garbage collected
    freeConnections.clear();
    activeConnections.clear();

    if (error)
    {
      String msg = Translate.get("connection.free.connections.failed");
      logger.error(msg);
      throw new SQLException(msg);
    }
  }

  public int getCurrentNumberOfConnections()
  {
    return poolSize;
  }

}

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