# RemoteLegacyJavaAppserverClient.java

    /*
    ** Module   : RemoteLegacyJavaAppserverClient.java
    ** Abstract : Implementation for remote Java clients connecting to a FWD server (running in separate JVM).
    **
    ** Copyright (c) 2022-2025, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- ---------------------------------------Description----------------------------------------
    ** 001 CA  20221031 Created initial version.
    ** 002 GBB 20240610 LegacyAppServerWork replaced by Consumer<LegacyServiceWorker>.
    ** 003 CA  20250324 Improvements for remote FWD OpenClient connections: ensure that the remote side uses a
    **                  single connection to the FWD server, and also use a client-side pool of worker threads to
    **                  send the requests (the pool size is in sync with the maximum agents available to process
    **                  requests).
    */

    /*
    ** 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
    **     publicity purposes without written authorization.
    **
    **   2. No Misrepresentation of Affiliation.
    **
    **     You may not represent yourself as Golden Code Development Corporation or FWD.
    **
    **     You may not represent yourself for publicity purposes as associated with
    **     Golden Code Development Corporation, FWD, or any author or contributor to
    **     the covered work, without written authorization.
    **
    **   3. No Misrepresentation of Source or Origin.
    **
    **     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.util;

    import java.util.*;
    import java.util.concurrent.*;
    import java.util.logging.Level;

    import com.goldencode.p2j.main.*;

    /**
     * A Java client which connected to a remote FWD server.
     */
    class RemoteLegacyJavaAppserverClient
    extends LegacyJavaAppserverClient
    {
       /** Flag indicating if this client has disconnected. */
       private boolean disconnected = false;

       /**
        * Initialize this client with the given worker pool.
        *
        * @param    pool
        *           The pool of workers where tasks will be forwarded, to be executed on the remote appserver.
        */
       public RemoteLegacyJavaAppserverClient(RemoteAppServerConnectionPool pool)
       {
          super(pool);
       }

       /**
        * Connect to the remote FWD server.
        *
        * @return   <code>true</code> if it connected.
        */
       @Override
       public boolean connect()
       {
          if (disconnected)
          {
             String appserver = pool.getAppserver();
             LOG.log(Level.SEVERE, "FWD '" + appserver + "' appserver client is disconnect, can not reconnect.");
             return false;
          }

          return super.connect();
       }

       /**
        * Terminate all sessions on this client.
        */
       @Override
       public void disconnect()
       {
          this.disconnected = true;
          cancelAllRequests();

          CountDownLatch disc = new CountDownLatch(pool.size());

          LegacyAppServerWork work = (worker) ->
          {
             try
             {
                Set<ProxyProcedureWrapper> procedures = worker.getProcedures(sessionID);
                for (ProxyProcedureWrapper proc : procedures)
                {
                   worker.getHelper().deleteProcedure(proc);
                   worker.removeProcedure(sessionID, proc);
                }

                worker.removeProcedures(sessionID);
                worker.getHelper().disconnect();
             }
             finally
             {
                disc.countDown();
             }
          };

          pool.broadcast(work);

          try
          {
             disc.await();
          }
          catch (InterruptedException e)
          {
             // ignore
          }
          finally
          {
             pool.terminateWorkers();
             connectionID = null;
          }
       }

       /**
        * Cancel all the requests active on this client.
        */
       @Override
       public void cancelAllRequests()
       {
          if (connectionID == null)
          {
             return;
          }

          LegacyAppServerWork work = (worker) ->
          {
             worker.getHelper().sendStop();
          };

          pool.broadcast(work);
       }

       /**
        * Send the given task to be executed by one of the workers in the {@link #pool}.
        *
        * @param    work
        *           The work to be executed.
        *
        * @throws   RuntimeException
        *           If the request was not posted to any worker or the time allowed to execute has elapsed.
        */
       @Override
       protected boolean execute(LegacyAppServerWork work)
       {
          if (disconnected)
          {
             String appserver = pool.getAppserver();
             LOG.log(Level.SEVERE, "FWD '" + appserver + "' appserver client is not connected.");
             return false;
          }

          return super.execute(work);
       }
    }