# PersistenceInvocationHandler.java

    /*
    ** Module   : PersistenceInvocationHandler.java
    ** Abstract : Handler for the dynamic proxy of a persistence instance
    **
    ** Copyright (c) 2024, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- ---------------------------------------Description----------------------------------------
    ** 001 SB  20240828 Created initial version.
    ** 002 OM  20240910 Fixed javadoc. Optimized imports.
    ** 003 OM  20241128 Multi-tenant runtime support: selected the proper persistence context, eventually
    **                  based on [sharedDb] parameter.
    ** 004 ES  20250424 Handle StopConditionException through ErrorManager.
    */

    /*
    ** 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.
    **
    **     You must preserve all legal notices or author attributions in the covered
    **     work or Appropriate Legal Notices displayed by works containing the covered
    **     work.  You may not remove from the covered work any author or developer
    **     credit already included within the covered work.
    **
    **   1. No License To Use Trademarks.
    **
    **     This license does not grant any license or rights to use the trademarks
    **     Golden Code, FWD, any Golden Code or FWD logo, or any other trademarks
    **     of Golden Code Development Corporation. You are not authorized to use the
    **     name Golden Code, FWD, or the names of any author or contributor, for
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    **
    **     You may not represent the covered work as solely your work.  All modified
    **     versions of the covered work must be marked in a reasonable way to make it
    **     clear that the modified work is not originating from Golden Code Development
    **     Corporation or FWD.  All modified versions must contain the notices of
    **     attribution required in this license.
    */

    package com.goldencode.p2j.persist;

    import com.goldencode.p2j.util.*;
    import com.goldencode.p2j.util.logging.*;
    import java.lang.reflect.*;
    import java.util.logging.Level;

    /**
     * Handler for the dynamic proxy of a persistence instance. Used for situations where {@link Persistence}
     * methods are to be used but with slight exceptions or modifications in execution. To be used for
     * {@link UnsafePersistence}.
     */
    class PersistenceInvocationHandler
    implements InvocationHandler
    {
       /** The logger. */
       private static final CentralLogger LOG = CentralLogger.get(PersistenceInvocationHandler.class.getName());

       /** The persistence instance. */
       private final Persistence persistence;

       /**
        * The constructor.
        *
        * @param   persistence
        *          The persistence instance to be used as a proxy.
        */
       public PersistenceInvocationHandler(Persistence persistence)
       {
          this.persistence = persistence;
       }

       /**
        * The function responsible for invoking and handling the invocation event.
        */
       @Override
       public Object invoke(Object proxy, Method method, Object[] args)
       throws Throwable
       {
          // create a persistence context if there isn't one already
          BufferManager.get().getTxWrapperHelper().maybeActivateTxWrapper(
                persistence.getDatabase(Persistence.PRIVATE_CTX));
          persistence.setUnsafe(true, Persistence.PRIVATE_CTX);
          Object result = null;
          try
          {
             result = method.invoke(persistence, args);
          }
          catch (InvocationTargetException | IllegalAccessException | IllegalArgumentException exc)
          {
             Throwable cause = exc.getCause();
             if (cause instanceof PersistenceException)
             {
                if (LOG.isLoggable(Level.WARNING))
                {
                   LOG.log(Level.WARNING,
                           "Query for database " + persistence.getDatabase(Persistence.PRIVATE_CTX) +
                           " has failed in unsafe mode!");
                }

                throw cause;
             }
             else
             {
                ErrorManager.handleStopException(new StopConditionException(exc));
             }
          }
          finally
          {
             persistence.setUnsafe(false, Persistence.PRIVATE_CTX);
          }

          return result;
       }
    }