# UIStatementsAspect.java

    /*
    ** Module   : UIStatementsAspect.java
    ** Abstract : An aspect which associates GenericFrame APIs with their legacy 4GL UI statement.
    **
    ** Copyright (c) 2015-2017, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- ---------------------------------Description----------------------------------
    ** 001 CA  20151112 Created initial version.
    ** 002 CA  20160624 Fix for frame-related statements used with STDOUT, in appserver case.
    */
    /*
    ** 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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    **     Golden Code Development Corporation, FWD, or any author or contributor to
    **     the covered work, without written authorization.
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    **
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    **     versions of the covered work must be marked in a reasonable way to make it
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    **     Corporation or FWD.  All modified versions must contain the notices of
    **     attribution required in this license.
    */

    package com.goldencode.p2j.aspects.ui;

    import org.aspectj.lang.*;
    import org.aspectj.lang.annotation.*;

    import com.goldencode.p2j.ui.*;
    import com.goldencode.p2j.util.*;

    /**
     * For {@link GenericFrame} APIs emitted at conversion (and associated with 4GL UI statements),
     * it will save the UI statement currently being executed, to distinguish between external calls
     * of these APIs (from legacy converted code) and from internal P2J calls (for example,
     * {@link GenericFrame#view} is called internally in some cases).
     * <p>
     * When one of these APIs is executed, {@link GenericFrame#setStatement} will save the passed
     * {@link UIStatement}, only if one is not already being executed - thus calls external from
     * P2J code will have priority over internal P2J calls.
     */
    @Aspect
    public class UIStatementsAspect
    {
       /**
        * Triggered around {@link GenericFrame#view} statements, to set the {@link UIStatement#VIEW}.
        *
        * @param   thisJoinPoint
        *          A join point reference.
        *
        * @return  The value of the join point method.
        *
        * @throws  Throwable
        *          Any exceptions are untouched propagated out.
        */
       @Around("execution(public void com.goldencode.p2j.ui.GenericFrame.view*(..))")
       public Object view(ProceedingJoinPoint thisJoinPoint)
       throws Throwable
       {
          return statementWorker(thisJoinPoint, UIStatement.VIEW);
       }

       /**
        * Triggered around {@link GenericFrame#hide} statements, to set the {@link UIStatement#HIDE}.
        *
        * @param   thisJoinPoint
        *          A join point reference.
        *
        * @return  The value of the join point method.
        *
        * @throws  Throwable
        *          Any exceptions are untouched propagated out.
        */
       @Around("execution(public void com.goldencode.p2j.ui.GenericFrame.hide*(..))")
       public Object hide(ProceedingJoinPoint thisJoinPoint)
       throws Throwable
       {
          return statementWorker(thisJoinPoint, UIStatement.HIDE);
       }

       /**
        * Triggered around {@link GenericFrame#display} statements, to set the
        * {@link UIStatement#DISPLAY}.
        *
        * @param   thisJoinPoint
        *          A join point reference.
        *
        * @return  The value of the join point method.
        *
        * @throws  Throwable
        *          Any exceptions are untouched propagated out.
        */
       @Around("execution(public void com.goldencode.p2j.ui.GenericFrame.display*(..))")
       public Object display(ProceedingJoinPoint thisJoinPoint)
       throws Throwable
       {
          return statementWorker(thisJoinPoint, UIStatement.DISPLAY);
       }

       /**
        * Triggered around {@link GenericFrame#enable} statements, to set the {@link UIStatement#ENABLE}.
        *
        * @param   thisJoinPoint
        *          A join point reference.
        *
        * @return  The value of the join point method.
        *
        * @throws  Throwable
        *          Any exceptions are untouched propagated out.
        */
       @Around("execution(public void com.goldencode.p2j.ui.GenericFrame.enable*(..))")
       public Object enable(ProceedingJoinPoint thisJoinPoint)
       throws Throwable
       {
          return statementWorker(thisJoinPoint, UIStatement.ENABLE);
       }

       /**
        * Triggered around {@link GenericFrame#disable} statements, to set the
        * {@link UIStatement#DISABLE}.
        *
        * @param   thisJoinPoint
        *          A join point reference.
        *
        * @return  The value of the join point method.
        *
        * @throws  Throwable
        *          Any exceptions are untouched propagated out.
        */
       @Around("execution(public void com.goldencode.p2j.ui.GenericFrame.disable*(..))")
       public Object disable(ProceedingJoinPoint thisJoinPoint)
       throws Throwable
       {
          return statementWorker(thisJoinPoint, UIStatement.DISABLE);
       }

       /**
        * Triggered around {@link GenericFrame#set} statements, to set the {@link UIStatement#SET}.
        *
        * @param   thisJoinPoint
        *          A join point reference.
        *
        * @return  The value of the join point method.
        *
        * @throws  Throwable
        *          Any exceptions are untouched propagated out.
        */
       @Around("execution(public void com.goldencode.p2j.ui.GenericFrame.set(..))")
       public Object set(ProceedingJoinPoint thisJoinPoint)
       throws Throwable
       {
          return statementWorker(thisJoinPoint, UIStatement.SET);
       }

       /**
        * Triggered around {@link GenericFrame#promptFor} statements, to set the
        * {@link UIStatement#PROMPT_FOR}.
        *
        * @param   thisJoinPoint
        *          A join point reference.
        *
        * @return  The value of the join point method.
        *
        * @throws  Throwable
        *          Any exceptions are untouched propagated out.
        */
       @Around("execution(public void com.goldencode.p2j.ui.GenericFrame.promptFor*(..))")
       public Object promptFor(ProceedingJoinPoint thisJoinPoint)
       throws Throwable
       {
          return statementWorker(thisJoinPoint, UIStatement.PROMPT_FOR);
       }

       /**
        * Triggered around {@link GenericFrame#update} statements,
        * to set the {@link UIStatement#UPDATE}.
        *
        * @param   thisJoinPoint
        *          A join point reference.
        *
        * @return  The value of the join point method.
        *
        * @throws  Throwable
        *          Any exceptions are untouched propagated out.
        */
       @Around("execution(public void com.goldencode.p2j.ui.GenericFrame.update*(..))")
       public Object update(ProceedingJoinPoint thisJoinPoint)
       throws Throwable
       {
          return statementWorker(thisJoinPoint, UIStatement.UPDATE);
       }

       /**
        * A worker to set and restore the UI statement used by the current frame.
        *
        * @param   thisJoinPoint
        *          A join point reference.
        * @param   stmt
        *          The 4GL {@link UIStatement} associated with the {@link GenericFrame} API.
        * @return  The value of the join point method.
        *
        * @throws Throwable
        *          Any exceptions are untouched propagated out.
        */
       private Object statementWorker(ProceedingJoinPoint thisJoinPoint, UIStatement stmt)
       throws Throwable
       {
          GenericFrame frame = (GenericFrame) thisJoinPoint.getThis();

          if (AppServerManager.isRemote())
          {
             Object[] args = thisJoinPoint.getArgs();
             if (args.length >= 1 && args[0] instanceof Stream)
             {
                // explicitly redirected, nothing special
             }
             else
             {
                boolean isInput = (stmt == UIStatement.ENABLE ||
                                   stmt == UIStatement.UPDATE ||
                                   stmt == UIStatement.SET    ||
                                   stmt == UIStatement.PROMPT_FOR);
                if (isInput)
                {
                   if (UnnamedStreams.input() == null)
                   {
                      if (stmt == UIStatement.ENABLE)
                      {
                         String errMsg =
                            "Cannot execute ENABLE statement when input stream is not the screen";
                         ErrorManager.displayError(4018, errMsg);

                         throw new StopConditionException(errMsg);
                      }
                      else
                      {
                         // UPDATE/SET/PROMPT-FOR 'abends' (but does not terminate the agent)!
                         LogicalTerminal.stopBatchSession();
                      }

                      return null;
                   }
                }
                else
                {
                   if (UnnamedStreams.output() == null)
                   {
                      // all non-interactive frame stmts are no-oped, if the output is not redirected
                      return null;
                   }
                }
             }
          }

          boolean pop = frame.setStatement(stmt);

          try
          {
             return thisJoinPoint.proceed();
          }

          finally
          {
             if (pop)
             {
                frame.resetStatement();
             }
          }
       }
    }