# BlockRunner.java

    /*
    ** Module   : BlockRunner.java
    ** Abstract : Helper to execute a 4GL code block with managed errors.
    **
    ** Copyright (c) 2017-2023, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- ---------------------------------Description---------------------------------
    ** 001 GES 20171206 First version.
    ** 002 CA  20231129 Use method references where possible.
    */

    /*
    ** 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.function.*;
    import com.goldencode.p2j.net.*;

    /**
     * Helper to execute a 4GL code block with managed errors. Some of the data is intentionally
     * public so that it is easily accessed after block execution.
     */
    public class BlockRunner
    {
       /** Return value from the code block execution. */
       public BaseDataType result = null;

       /** <code>true</code> if an error condition is raised in the code execution. */
       public boolean error = false;

       /** <code>true</code> if a stop condition is raised in the code execution. */
       public boolean stop = false;

       /** <code>true</code> if a quit condition is raised in the code execution. */
       public boolean quit = false;

       /** Error number of the error condition that was raised in the code execution. */
       public int errorNumber = 0;

       /** Error message of the error condition that was raised in the code execution. */
       public String errorMessage = null;

       /** Main code block to execute. */
       private Function<BlockRunner, BaseDataType> block = null;

       /** Post-processing block (optional). */
       private Runnable post = null;

       /** Flag to determine if the code is run in silent error mode or not. */
       private boolean silent = false;

       /**
        * Create an instance to execute the given code block(s) WITHOUT silent mode.
        *
        * @param    block
        *           The main code block to execute. Must NOT be <code>null</code>.
        */
       public BlockRunner(Function<BlockRunner, BaseDataType> block)
       {
          this.block  = block;
       }

       /**
        * Create an instance to execute the given code block(s).
        *
        * @param    block
        *           The main code block to execute. Must NOT be <code>null</code>.
        * @param    post
        *           Optional block to execute as post-processing. It will happen in a finally block
        *           if this is non-null.
        * @param    silent
        *           <code>true</code> if this should be executed in silent error mode.
        */
       public BlockRunner(Function<BlockRunner, BaseDataType> block, Runnable post, boolean silent)
       {
          this.block  = block;
          this.post   = post;
          this.silent = silent;
       }

       /**
        * Run the code block.
        */
       public void execute()
       {
          if (silent)
          {
             ErrorManager.silent(this::process);
          }
          else
          {
             this.process();
          }
       }

       /**
        * Execute the code block with integrated error management.
        */
       private void process()
       {
          try
          {
             result = block.apply(this);
          }
          catch (Throwable t)
          {
             // check for quit, stop, error
             Throwable err = t;

             while (err != null)
             {
                if (err instanceof SilentUnwindException)
                {
                   throw (SilentUnwindException) err;
                }
                else if (err instanceof ErrorConditionException)
                {
                   error        = true;
                   errorNumber  = ((ErrorConditionException) err).getProgressErrorCode();
                   errorMessage = err.getMessage();
                   break;
                }
                else if (err instanceof QuitConditionException)
                {
                   quit = true;
                   break;
                }
                else if (err instanceof StopConditionException)
                {
                   stop = true;
                   break;
                }

                err = err.getCause();
             }

             if (!(error || quit || stop))
             {
                // assume an ERROR condition for everything else
                error        = true;
                errorNumber  = -1;
                errorMessage = t.getMessage();
             }
          }
          finally
          {
             if (post != null)
             {
                post.run();
             }
          }

          if (silent && error && ErrorManager.isErrorFlag())
          {
             // check the error messages - only first message will be reported
             error = true;

             if (ErrorManager.numErrors().intValue() > 0)
             {
                errorNumber  = ErrorManager.getErrorNumber(1).intValue();
                errorMessage = ErrorManager.getErrorText(1).toStringMessage();
             }
          }
       }
    }