How to use

ConnectionCustomizer

in

org.eclipse.persistence.internal.databaseaccess

/**
* Clear and remove customizer if its session is the same as the passed one;
* in case prevCustomizer exists set it as a new customizer.
* Called when ClientSession releases write accessor:
* if the customizer was created by the ClientSession it's removed, and
* the previous customizer (that ConnectionPool had set) is brought back;
* otherwise the customizer (created by ConnectionPool) is kept.
* Ignored if there's no customizer. 
*/
public void releaseCustomizer(AbstractSession session) {
  if(customizer != null) {
    if(customizer.getSession() == session) {
      if(customizer.isActive()) {
        customizer.clear();
      }
      if(customizer.getPrevCustomizer() == null) {
        customizer = null;
      } else {
        setCustomizer(customizer.getPrevCustomizer());
      }
    }
  }
}

/**
 * Set customizer, customize the connection if it's available.
 */
protected void setCustomizer(ConnectionCustomizer newCustomizer) {
  this.customizer = newCustomizer;
  if(getDatasourceConnection() != null) {
    customizer.customize();
  }
}

/**
 * Clone the accessor.
 */
public Object clone() {
  try {
    DatasourceAccessor accessor = (DatasourceAccessor)super.clone();
    if(accessor.customizer != null) {
      accessor.customizer.setAccessor(accessor);
    }
    return accessor;
  } catch (CloneNotSupportedException exception) {
    throw new InternalError("clone not supported");
  }
}

/**
 * Clear customizer if it's active and set it to null.
 * Called by the same object that has created customizer (DatabaseSession, ConnectionPool) when
 * the latter is no longer required, typically before releasing the accessor.
 * Ignored if there's no customizer. 
 */
public void releaseCustomizer() {
  if(customizer != null) {
    if(customizer.isActive()) {
      customizer.clear();
    }
    customizer = null;
  }
}

if(customizer.getSession() == session) {
  return;
  if(customizer.isActive()) {
    customizer.clear();
  newCustomizer = ConnectionCustomizer.createEmptyCustomizer(session);
  newCustomizer.setPrevCustomizer(customizer);
    if(customizer.isActive()) {
      customizer.clear();
    newCustomizer.setPrevCustomizer(customizer);
    setCustomizer(newCustomizer);

if(customizer.getSession() == session) {
  return;
  if(customizer.isActive()) {
    customizer.clear();
  newCustomizer = ConnectionCustomizer.createEmptyCustomizer(session);
  newCustomizer.setPrevCustomizer(customizer);
    if(customizer.isActive()) {
      customizer.clear();
    newCustomizer.setPrevCustomizer(customizer);
    setCustomizer(newCustomizer);

/**
 * Clear customizer if it's active and set it to null.
 * Called by the same object that has created customizer (DatabaseSession, ConnectionPool) when
 * the latter is no longer required, typically before releasing the accessor.
 * Ignored if there's no customizer. 
 */
public void releaseCustomizer() {
  if(customizer != null) {
    if(customizer.isActive()) {
      customizer.clear();
    }
    customizer = null;
  }
}

/**
* Clear and remove customizer if its session is the same as the passed one;
* in case prevCustomizer exists set it as a new customizer.
* Called when ClientSession releases write accessor:
* if the customizer was created by the ClientSession it's removed, and
* the previous customizer (that ConnectionPool had set) is brought back;
* otherwise the customizer (created by ConnectionPool) is kept.
* Ignored if there's no customizer. 
*/
public void releaseCustomizer(AbstractSession session) {
  if(customizer != null) {
    if(customizer.getSession() == session) {
      if(customizer.isActive()) {
        customizer.clear();
      }
      if(customizer.getPrevCustomizer() == null) {
        customizer = null;
      } else {
        setCustomizer(customizer.getPrevCustomizer());
      }
    }
  }
}

if(customizer.getSession() == session) {
  return;
  if(customizer.isActive()) {
    customizer.clear();
  newCustomizer = ConnectionCustomizer.createEmptyCustomizer(session);
  newCustomizer.setPrevCustomizer(customizer);
    if(customizer.isActive()) {
      customizer.clear();
    newCustomizer.setPrevCustomizer(customizer);
    setCustomizer(newCustomizer);

/**
 * Clear customizer if it's active and set it to null.
 * Called by the same object that has created customizer (DatabaseSession, ConnectionPool) when
 * the latter is no longer required, typically before releasing the accessor.
 * Ignored if there's no customizer.
 */
public void releaseCustomizer() {
  if(customizer != null) {
    if(customizer.isActive()) {
      customizer.clear();
    }
    customizer = null;
  }
}

/**
 * Set customizer, customize the connection if it's available.
 */
protected void setCustomizer(ConnectionCustomizer newCustomizer) {
  this.customizer = newCustomizer;
  if(getDatasourceConnection() != null) {
    customizer.customize();
  }
}

/**
 * Clone the accessor.
 */
public Object clone() {
  try {
    DatasourceAccessor accessor = (DatasourceAccessor)super.clone();
    if(accessor.customizer != null) {
      accessor.customizer.setAccessor(accessor);
    }
    return accessor;
  } catch (CloneNotSupportedException exception) {
    throw new InternalError("clone not supported");
  }
}

/**
* Clear and remove customizer if its session is the same as the passed one;
* in case prevCustomizer exists set it as a new customizer.
* Called when ClientSession releases write accessor:
* if the customizer was created by the ClientSession it's removed, and
* the previous customizer (that ConnectionPool had set) is brought back;
* otherwise the customizer (created by ConnectionPool) is kept.
* Ignored if there's no customizer.
*/
public void releaseCustomizer(AbstractSession session) {
  if(customizer != null) {
    if(customizer.getSession() == session) {
      if(customizer.isActive()) {
        customizer.clear();
      }
      if(customizer.getPrevCustomizer() == null) {
        customizer = null;
      } else {
        setCustomizer(customizer.getPrevCustomizer());
      }
    }
  }
}

/**
 * Close the accessor's connection.
 * This is used only for external connection pooling
 * when it is intended for the connection to be reconnected in the future.
 */
public void closeConnection() {
  try {
    if (this.datasourceConnection != null) {
      if (isDatasourceConnected()) {
        if(currentSession != null) {
          currentSession.preDisconnectExternalConnection(this);
        }
        if(customizer != null && customizer.isActive()) {
          customizer.clear();
        }
        closeDatasourceConnection();
      }
      this.datasourceConnection = null;
    }
  } catch (DatabaseException exception) {
    // Ignore
    this.datasourceConnection = null;
  } finally {
    currentSession = null;
  }
}

/**
 * Set customizer, customize the connection if it's available.
 */
protected void setCustomizer(ConnectionCustomizer newCustomizer) {
  this.customizer = newCustomizer;
  if(getDatasourceConnection() != null) {
    customizer.customize();
  }
}

/**
 * Clone the accessor.
 */
public Object clone() {
  try {
    DatasourceAccessor accessor = (DatasourceAccessor)super.clone();
    if(accessor.customizer != null) {
      accessor.customizer.setAccessor(accessor);
    }
    return accessor;
  } catch (CloneNotSupportedException exception) {
    throw new InternalError("clone not supported");
  }
}

/**
* This method is called by reestablishConnection.
* Nothing needs to be done in case customize is not active (customization hasn't been applied yet). 
* to repair existing customizer after connection became invalid.
* However if connection has been customized then
* if connection is still there and deemed to be valid - clear customization.
* Otherwise (or if clear fails) remove customizer and set its prevCustomizer as a new customizer,
* then re-create customizer using the same session as the original one.
*/
protected void reestablishCustomizer() {
  if(customizer != null && customizer.isActive()) {
    if(isValid()) {
      // the method eats SQLException in case of a failure.   
      customizer.clear();
    } else {
      // It's an invalid connection - don't bother trying to clear customization.
      AbstractSession customizerSession = (AbstractSession)customizer.getSession();
      // need this so that the new customizer has the same prevCustomizer as the old one.
      customizer = customizer.getPrevCustomizer();
      // customizer recreated - it's the same as the original one, but not active.
      createCustomizer(customizerSession);
    }
  }
}

/**
 * Close the accessor's connection.
 * This is used only for external connection pooling
 * when it is intended for the connection to be reconnected in the future.
 */
public void closeConnection() {
  try {
    if (this.datasourceConnection != null) {
      if (isDatasourceConnected()) {
        if(currentSession != null) {
          currentSession.preReleaseConnection(this);
        }
        if(customizer != null && customizer.isActive()) {
          customizer.clear();
        }
        closeDatasourceConnection();
      }
      this.datasourceConnection = null;
    }
  } catch (DatabaseException exception) {
    // Ignore
    this.datasourceConnection = null;
  } finally {
    currentSession = null;
  }
}

/**
 * Connect to the database.
 * Exceptions are caught and re-thrown as EclipseLink exceptions.
 */
protected void connectInternal(Login login, AbstractSession session) throws DatabaseException {
  try{
    this.datasourceConnection = login.connectToDatasource(this, session);
    this.isConnected = true;
    if(this.customizer != null) {
      customizer.customize();
    }
  }catch (DatabaseException ex){
    //Set the accessor to ensure the retry code has an opportunity to retry.
    ex.setAccessor(this);
    throw ex;
  }
}

/**
* This method is called by reestablishConnection.
* Nothing needs to be done in case customize is not active (customization hasn't been applied yet).
* to repair existing customizer after connection became invalid.
* However if connection has been customized then
* if connection is still there and deemed to be valid - clear customization.
* Otherwise (or if clear fails) remove customizer and set its prevCustomizer as a new customizer,
* then re-create customizer using the same session as the original one.
*/
protected void reestablishCustomizer() {
  if(customizer != null && customizer.isActive()) {
    if(isValid()) {
      // the method eats SQLException in case of a failure.
      customizer.clear();
    } else {
      // It's an invalid connection - don't bother trying to clear customization.
      AbstractSession customizerSession = (AbstractSession)customizer.getSession();
      // need this so that the new customizer has the same prevCustomizer as the old one.
      customizer = customizer.getPrevCustomizer();
      // customizer recreated - it's the same as the original one, but not active.
      createCustomizer(customizerSession);
    }
  }
}