DirtyShareSupport.java

/*
** Module   : DirtyShareSupport.java
** Abstract : Enables or disables certain dirty share features, including dirty share impact logging
**
** Copyright (c) 2020-2024, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------------Description---------------------------------------
** 001 ECF 20200701 Created initial version. Enables/disables dirty share features globally.
** 002 GBB 20230512 Logging methods replaced by CentralLogger/ConversionStatus.
** 003 SVL 20230516 Support for more granular configuration of dirty sharing functionality.
** 004 DDF 20230620 Replaced static initialization of values from the directory configuration with
**                  a method called at server bootstrap.
**     DDF 20230627 Made members private and accessible through static methods and used a standard 
**                  handling for directory binding.
** 005 TJD 20240408 Renamed isEnabledCrossSection to isEnabledCrossSession
** 006 AL2 20241105 Disable cross-session dirty-share by default.
*/

/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
** GNU Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
** 
** Additional terms under GNU Affero GPL version 3 section 7:
** 
**   Under Section 7 of the GNU Affero GPL version 3, the following additional
**   terms apply to the works covered under the License.  These additional terms
**   are non-permissive additional terms allowed under Section 7 of the GNU
**   Affero GPL version 3 and may not be removed by you.
** 
**   0. Attribution Requirement.
** 
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*/

package com.goldencode.p2j.persist.dirty;

import com.goldencode.p2j.directory.*;
import com.goldencode.p2j.util.*;
import com.goldencode.p2j.util.logging.*;

/**
 * This class globally enables/disables the dirty share feature and optionally collects information about
 * dirty share use in an application. The information collected can include table/DMO and index encountered
 * for which a record search's results have been changed by dirty share information from the current or
 * another session. It may optionally include the location (file and line number) in an application where
 * such use was found. The more detailed the information collected, the higher the impact on the runtime
 * performance of an application.
 * <p>
 * The logging level determines whether and how much information to collect:
 * <ul>
 * <li>INFO and higher: no information is collected;</li>
 * <li>FINE: the table/DMO and index for which a record search was affected by a dirty read is reported;</li>
 * <li>FINEST: additionally, the file and line number of application source code which led to the dirty
 *     read is reported</li>
 * </ul>
 * <p>
 * The INFO level (or higher) is intended for production use. FINE may have an impact on performance and
 * will have an impact on memory use. FINEST will likely have a noticeable impact on performance and will
 * use more memory.
 * <p>
 * The collected information is aggregated and reported in the server log at server shutdown.
 */
public final class DirtyShareSupport
{
   /** Logger */
   private static final CentralLogger log = CentralLogger.get(DirtyShareSupport.class.getName());
   
   /**
    * {@code true} if cross-session dirty sharing is enabled.
    */
   private static boolean enabledCrossSession = false;

   /**
    * {@code true} if dirty sharing within the same session is enabled.
    */
   private static boolean enabledIntraSession = true;

   /**
    * Flag which overrides the absence of DMO dirty-read annotations to force dirty sharing across sessions.
    */
   private static boolean forceCrossSession = false;

   /**
    * Flag which overrides the absence of DMO dirty-intra-read annotations to force dirty sharing within the
    * same session.
    */
   private static boolean forceIntraSession = true;

   /**
    * {@code true} if global notifications are enabled for cross-session dirty sharing.
    */
   private static boolean globalNotifications = false;
   
   /**
    * Method called at server bootstrap that initializes values from the directory
    * configuration. Until this method is called, default values are used.
    */
   public static void bootstrap()
   {
      DirectoryService ds = DirectoryService.getInstance();
      if (ds != null)
      {
         if (!ds.bind())
         {
            throw new RuntimeException("Directory bind failed");
         }
         
         try
         {
            // configure dirty sharing from the directory
            enabledCrossSession = Utils.getDirectoryNodeBoolean(ds,
                     "persistence/dirty-cross-share", false, false);
            enabledIntraSession = Utils.getDirectoryNodeBoolean(ds,
                     "persistence/dirty-intra-share", true, false);
            forceCrossSession = Utils.getDirectoryNodeBoolean(ds,
                     "persistence/force-dirty-cross-share", false, false);
            forceIntraSession = Utils.getDirectoryNodeBoolean(ds,
                     "persistence/force-dirty-intra-share", true, false);
            globalNotifications = Utils.getDirectoryNodeBoolean(ds,
                     "persistence/dirty-share-global-notifications", false, false);
         }
         finally
         {
            ds.unbind();
         }
      }
   }
   
   /**
    * Returns the value of the flag that indicates if cross-session dirty sharing is enabled.
    * 
    * @return  {@code true} if cross-session dirty sharing is enabled,
    *          {@code false} otherwise.
    */
   public static boolean isEnabledCrossSession()
   {
      return enabledCrossSession;
   }
   
   /**
    * Returns the value of the flag that indicates if dirty sharing within the same session is enabled.
    * 
    * @return  {@code true} if dirty sharing within the same session is enabled,
    *          {@code false} otherwise.
    */
   public static boolean isEnabledIntraSession()
   
   {
      return enabledIntraSession;
   }
   
   /**
    * Returns the value of the flag that indicates if dirty sharing is forced across sessions.
    * 
    * @return  {@code true} if dirty sharing is forced across sessions,
    *          {@code false} otherwise.
    */
   public static boolean isForceCrossSession()
   {
      return forceCrossSession;
   }
   
   /**
    * Returns the value of the flag that indicates if dirty sharing is forced within the same session.
    * 
    * @return  {@code true} if dirty sharing is forced within the same session,
    *          {@code false} otherwise.
    */
   public static boolean isForceIntraSession()
   {
      return forceIntraSession;
   }
   
   /**
    * Returns the value of the flag that indicates if global notifications are enabled for 
    * cross-session dirty sharing.
    * 
    * @return  {@code true} if global notifications are enabled for cross-session dirty sharing,
    *          {@code false} otherwise.
    */
   public static boolean isGlobalNotificationEnabled()
   {
      return globalNotifications;
   }
}