# MetaTableWrapper.java

    /*
    ** Module   : MetaTableWrapper.java
    ** Abstract : Wraps data for operations with meta table
    **
    ** Copyright (c) 2013-2024, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- --------------------------------Description----------------------------------
    ** 001 IAS 20200819 Created initial version.
    ** 002 CA  20200924 Replaced Method.invoke with ReflectASM.
    **     IAS 20210401 Re-worked for new ORM.
    **     ECF 20210910 Code cleanup.
    ** 003 GBB 20230512 Logging methods replaced by CentralLogger/ConversionStatus.
    ** 004 TJD 20240123 Java 17 compatibility updates
    */

    /*
    ** 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.persist.meta;

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

    import com.goldencode.p2j.persist.Record;
    import com.goldencode.p2j.persist.meta.UserTableStatUpdater.*;
    import com.goldencode.p2j.persist.orm.*;
    import com.goldencode.p2j.util.*;
    import com.goldencode.p2j.util.logging.*;
    import com.goldencode.proxy.*;

    /**
     * Wraps data for operations with meta table
     * @param <T> meta table DMO interface
     */
    public class MetaTableWrapper<T>
    {
       /** Logger */
       private static final CentralLogger LOG = CentralLogger.get(MetaTableWrapper.class);

       /** DMO class */
       private final Class<? extends Record> dmoClass;

       /** DMO methods map by name */
       private final Map<Method, Method> methodMap = new HashMap<>();

       /** DMO Impl object */
       private Object dmoImpl;

       /** Meta table DMO proxy */
       private final T metaTableProxy;

       /** Dummy empty class to be used as the super class for proxy. */
       public static class Empty {}

       /** DMO operations <code>InvocationHandler</code> */
       private final InvocationHandler handler = new InvocationHandler()
       {
          /**
           * Processes a method invocation on a proxy instance and returns the result.
           */
          @Override
          public Object invoke(Object proxy, Method method, Object[] args) throws Throwable
          {
             Method dmoMethod = methodMap.get(method);
             if (dmoMethod == null) {
                 throw new IllegalArgumentException("Unknown method: " + method.getName());
             }
             try
             {
                 return Utils.invoke(dmoMethod, dmoImpl, args);
             }
             catch(InvocationTargetException e)
             {
                 throw e.getTargetException();
             }
          }
       };

       /**
        * Constructor
        *
        * @param   facet
        *          DMO interface class
        * @param   ifName
        *          DMO interface class simple name
        */
       public MetaTableWrapper(Class<T> facet, String ifName)
       {
          String dmoName = String.format("%s._meta.%s", DmoMetadataManager.getDmoBasePackage(), ifName);
          Class<? extends Record> implementingClass = null;
          try
          {
             DmoMeta dmoInfo = DmoMetadataManager.getDmoInfo(Class.forName(dmoName));
             implementingClass = dmoInfo.getImplementationClass();
             this.metaTableProxy = ProxyFactory.getProxy(Empty.class, new Class<?>[]{facet}, handler);
             for (Method ifcMeth : MinimalUsertablestat.class.getMethods())
             {
                Method dmoMeth = implementingClass.getMethod(ifcMeth.getName(), ifcMeth.getParameterTypes());
                methodMap.put(ifcMeth, dmoMeth);
             }
          }
          catch (ClassNotFoundException | IllegalArgumentException | NoSuchMethodException e)
          {
             throw new RuntimeException("Error preparing MetaUsertablestat implementation class", e);
          }
          this.dmoClass = implementingClass;
       }

       /**
        * Get DMO interface class
        *
        * @return DMO interface class
        */
       public Class<? extends Record> getDmoClass()
       {
          return dmoClass;
       }

       /**
        * Get DMO methods map by name
        *
        * @return DMO methods map by name
        */
       public Map<Method, Method> getMethodMap()
       {
          return methodMap;
       }

       /**
        * Get meta table DMO proxy
        *
        * @return meta table DMO proxy
        */
       public T getMetaTableProxy()
       {
          return metaTableProxy;
       }

       /**
        * Set DMO Impl object
        *
        * @param   dmoImpl
        *          DMO Impl object
        */
       public void setDelegate(Object dmoImpl)
       {
          this.dmoImpl = dmoImpl;
       }
    }