protected void connectionClose(JdbcConnection jdbcConn) {
synchronized (jdbcConnections) {
jdbcConn.invalidate();
jdbcConnections.remove(jdbcConn);
ConnectionEvent event = new ConnectionEvent(this, ConnectionEvent.CONNECTION_CLOSED);
Object[] elements = listeners.toArray();
for (int i = 0; i < elements.length; i++) {
ConnectionEventListener eventListener = (ConnectionEventListener) elements[i];
eventListener.connectionClosed(event);
}