/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at
 * trunk/opends/resource/legal-notices/OpenDS.LICENSE
 * or https://OpenDS.dev.java.net/OpenDS.LICENSE.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at
 * trunk/opends/resource/legal-notices/OpenDS.LICENSE.  If applicable,
 * add the following below this CDDL HEADER, with the fields enclosed
 * by brackets "[]" replaced with your own identifying * information:
 *      Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 *
 *      Portions Copyright 2006 Sun Microsystems, Inc.
 */
package org.opends.server.api;



import org.opends.server.config.ConfigEntry;
import org.opends.server.config.ConfigException;
import org.opends.server.core.DirectoryException;
import org.opends.server.core.InitializationException;
import org.opends.server.core.Operation;



/**
 * This class defines the structure and methods that must be
 * implemented by a Directory Server work queue.  The work queue is
 * the component of the server that accepts requests from connection
 * handlers and ensures that they are properly processed.  The manner
 * in which the work queue is able to accomplish this may vary between
 * implementations, but in general it is assumed that one or more
 * worker threads will be associated with the queue and may be used to
 * process requests in parallel.
 */
public abstract class WorkQueue
{
  /**
   * Initializes this work queue based on the information in the
   * provided configuration entry.
   *
   * @param  configEntry  The configuration entry that contains the
   *                      information to use to initialize this work
   *                      queue.
   *
   * @throws  ConfigException  If the provided configuration entry
   *                           does not have a valid work queue
   *                           configuration.
   *
   * @throws  InitializationException  If a problem occurs during
   *                                   initialization that is not
   *                                   related to the server
   *                                   configuration.
   */
  public abstract void initializeWorkQueue(ConfigEntry configEntry)
         throws ConfigException, InitializationException;



  /**
   * Performs any necessary finalization for this work queue,
   * including ensuring that all active operations are interrupted or
   * will be allowed to complete, and that all pending operations will
   * be cancelled.
   *
   * @param  reason  The human-readable reason that the work queue is
   *                 being shut down.
   */
  public abstract void finalizeWorkQueue(String reason);



  /**
   * Submits an operation to be processed in the server.
   *
   * @param  operation  The operation to be processed.
   *
   * @throws  DirectoryException  If the provided operation is not
   *                              accepted for some reason (e.g., if
   *                              the server is shutting down or
   *                              already has too many pending
   *                              requests in the queue).
   */
  public abstract void submitOperation(Operation operation)
         throws DirectoryException;
}