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18.7 Connection Pooling

507

Listing 18.19 ConnectionPool.java (continued)

  public synchronized void free(Connection connection) {

    busyConnections.removeElement(connection);

    availableConnections.addElement(connection);

    // Wake up threads that are waiting for a connection

    notifyAll(); 

  }

  public synchronized int totalConnections() {

    return(availableConnections.size() +

           busyConnections.size());

  }

  /** Close all the connections. Use with caution:

   *  be sure no connections are in use before

   *  calling. Note that you are not required to

   *  call this when done with a ConnectionPool, since

   *  connections are guaranteed to be closed when

   *  garbage collected. But this method gives more control

   *  regarding when the connections are closed.

   */

  public synchronized void closeAllConnections() {

    closeConnections(availableConnections);

    availableConnections = new Vector();

    closeConnections(busyConnections);

    busyConnections = new Vector();

  }

  private void closeConnections(Vector connections) {

    try {

      for(int i=0; i