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

説明を見る。

package org.objectweb.cjdbc.controller.connection;

import java.io.Serializable;
import java.sql.Connection;
import java.util.EmptyStackException;

import org.objectweb.cjdbc.common.exceptions.UnreachableBackendException;
import org.objectweb.cjdbc.common.i18n.Translate;
import org.objectweb.cjdbc.common.xml.DatabasesXmlTags;

public class FailFastPoolConnectionManager
    extends
      AbstractPoolConnectionManager implements Serializable
{

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

  public Connection getConnection() throws UnreachableBackendException
  {
    if (!initialized)
    {
      logger.error(Translate.get("connection.request.not.initialized"));
      return null;
    }

    try
    { // Both freeConnections and activeConnections are synchronized
      Connection c = (Connection) freeConnections.pop();
      activeConnections.add(c);
      return c;
    }
    catch (EmptyStackException e)
    {
      synchronized (this)
      {
        int missing = poolSize
            - (activeConnections.size() + freeConnections.size());
        if (missing > 0)
        { // Re-allocate missing connections
          logger.info(Translate.get("connection.reallocate.missing", missing));
          Connection connectionToBeReturned = null;
          while (missing > 0)
          {
            Connection c = getConnectionFromDriver();
            if (c == null)
            {
              if (missing == poolSize)
              {
                logger.error(Translate.get("connection.backend.unreachable",
                    backendName));
                throw new UnreachableBackendException();
              }
              logger.warn(Translate
                  .get("connection.reallocate.failed", missing));
              break;
            }
            else
            {
              if (connectionToBeReturned == null)
                connectionToBeReturned = c;
              else
                freeConnections.add(c);
            }
            missing--;
          }
          return connectionToBeReturned;
        }
      }
      if (logger.isWarnEnabled())
        logger.warn(Translate.get("connection.backend.out.of.connections",
            new String[]{backendName, String.valueOf(poolSize)}));
      return null;
    }
  }

  public synchronized void releaseConnection(Connection c)
  {
    if (!initialized)
      return; // We probably have been disabled

    if (activeConnections.remove(c))
      freeConnections.push(c);
    else
      logger.error(Translate.get("connection.release.failed", c.toString()));
  }

  public synchronized void deleteConnection(Connection c)
  {
    if (!initialized)
      return; // We probably have been disabled

    if (activeConnections.remove(c))
    {
      Connection newConnection = getConnectionFromDriver();
      if (newConnection == null)
      {
        if (logger.isDebugEnabled())
          logger.error(Translate
              .get("connection.replaced.failed", c.toString()));
      }
      else
      {
        freeConnections.push(newConnection);
        if (logger.isDebugEnabled())
          logger.debug(Translate.get("connection.replaced.success", c
              .toString()));
      }
    }
    else
      logger.error(Translate.get("connection.replaced.failed.exception", c
          .toString()));
  }

  public String getXmlImpl()
  {
    StringBuffer info = new StringBuffer();
    info.append("<" + DatabasesXmlTags.ELT_FailFastPoolConnectionManager + " "
        + DatabasesXmlTags.ATT_poolSize + "=\"" + poolSize / 1000 + "\"/>");
    return info.toString();
  }

  protected Object clone() throws CloneNotSupportedException
  {
    return new FailFastPoolConnectionManager(backendUrl, backendName, rLogin,
        rPassword, driverPath, driverClassName, poolSize);
  }
}

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