# InputOutputExtentParameter.java

    /*
    ** Module   : InputOutputExtentParameter.java
    ** Abstract : Base class for special wrapper classes used for variables passed as
    **            input-output extent parameters to functions or procedures.
    **
    ** Copyright (c) 2014-2022, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- ---------------------------------------Description----------------------------------------
    ** 001 HC  20140613 Created initial version.
    ** 002 HC  20141106 Javadocs fixed
    ** 003 OM  20150706 Changed errors in initialization. Added implicit conversion support.
    ** 004 CA  20210609 Reworked INPUT/INPUT-OUTPUT parameters to a new approach, where they are explicitly
    **                  initialized at the method's execution, and not at the caller's arguments.
    **     CA  20210818 Fixed memptr parameter runtime - they share the 'pointer structure' with the passed
    **                  argument.
    **     TJD 20220504 Java 11 compatibility minor changes
    */
    /*
    ** 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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    **     work or Appropriate Legal Notices displayed by works containing the covered
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    **
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    **
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    */

    package com.goldencode.p2j.util;

    import java.lang.reflect.*;
    import java.util.logging.*;

    /**
     * Special wrapper used for variables passed as input-output extent parameters to
     * functions or procedures. On normal function and procedure exit, if the reference
     * for an output or input-output extent parameter has changed, this will update
     * the caller's variable reference too.
     */
    public abstract class InputOutputExtentParameter<T extends BaseDataType>
    extends AbstractExtentParameter<T>
    {
       /**
        * The constructor responsible for instance initialization by calling
        * {@link AbstractExtentParameter#AbstractExtentParameter(BaseDataType[])}.
        */
       public InputOutputExtentParameter()
       {
          super(null);
       }

       /**
        * This constructor allows to provide additional initialization logic of the variable
        * reference in the extending classes. The initialization logic is encapsulated in
        * {@link AbstractExtentParameter#AbstractExtentParameter(BaseDataType[])}.
        *
        * @param   variable
        *          A valid and initialized variable reference.
        */
       protected InputOutputExtentParameter(T[] variable)
       {
          super(variable);
       }

       /**
        * Initializes the indeterminate or determinate extent parameter reference depending
        * on the extent (array size) of the value returned by {@link #getVariable()}.
        * A zero value will initialize an indeterminate extent, a positive integer will
        * initialize a determinate extent. The extent will be registered with
        * {@link ArrayAssigner} accordingly.
        *
        * @return  The initialized indeterminate extent parameter reference.
        */
       @Override
       public T[] initParameter()
       {
          T[] var = getVariableSafe();
          return initParameter(var.length);
       }

       /**
        * Initializes the indeterminate or determinate extent parameter reference depending
        * on the {@code extent} value. A zero value will initialize an indeterminate
        * extent, a positive integer will initialize a determinate extent. The extent
        * will be registered with {@link ArrayAssigner} accordingly.
        *
        * @param   extent
        *          The parameter extent size.
        *
        * @return  The initialized indeterminate extent parameter reference.
        */
       @Override
       @SuppressWarnings("unchecked")
       public T[] initParameter(int extent)
       {
          // get the parameter reference
          T[] param = getParameter();
          if (param != null)
          {
             // the parameter is already initialized, just return it
             return param;
          }

          // initialize the parameter reference according to the variable reference
          T[] var = getVariableSafe();
          Class<?> varComponentClass = (paramType != null)
                                       ? paramType
                                       : var.getClass().getComponentType();
          boolean isMemptr = memptr.class.isAssignableFrom(varComponentClass);
          if (var.length < extent)
          {
             // The passed-in variable is an unfixed indeterminate extent, allocate
             // the parameter variable to the expected extent size.
             // Don't use ArrayAssigner.resize in this case, as it also copies decimal
             // precision. According to Progress behavior the newly allocated array
             // will have the default decimal precision.
             param = (T[]) Array.newInstance(varComponentClass, extent);
             for (int i = 0; i < extent; i++)
             {
                param[i] = (T) BaseDataType.generateUnknown(varComponentClass);

                if (isMemptr && i < var.length)
                {
                   ((memptr) param[i]).asParameter((memptr) var[i]);
                }
             }

             setParameter(param);
          }
          else
          {
             // The passed-in variable is a fixed extent, allocate the parameter
             // variable to its extent size.
             param = (T[]) Array.newInstance(varComponentClass, var.length);
             for (int i = 0; i < extent; i++)
             {
                // duplicate the array content
                try
                {
                   if (isMemptr)
                   {
                      memptr m = new memptr();
                      m.asParameter((memptr) var[i]);
                      param[i] = (T) m;
                   }
                   else
                   {
                      param[i] = (convCtor == null)
                                 ? (T) var[i].duplicate()
                                 : (T) convCtor.newInstance(var[i]);
                   }
                }
                catch (ReflectiveOperationException e)
                {
                   // constructor-related exception should not happen, the constructor have been
                   // detected based on actual data types
                   String msg = "Failed to convert INPUT-OUTPUT value from " + var[i].getClass() +
                                " to " + param[i].getTypeName() + " using " + convCtor +
                                " conversion constructor.";
                   LOG.log(Level.WARNING, msg);
                }
                if (decimal.class.equals(varComponentClass))
                {
                   // and set to the default decimal precision
                   ((decimal) param[i]).setPrecision(decimal.MAX_SCALE);
                }
             }

             setParameter(param);

             if (extent == 0)
             {
                // the result is registered as dynamic array
                ArrayAssigner.registerDynamicArray(param);

                // make sure this extent parameter is tracked by ArrayAssigner,
                // to handle parameter value updates on resizes for example
                ArrayAssigner.registerExtentParameter(this);
             }
          }

          return param;
       }
    }