BaseObject.java

/*
** Module   : BaseObject.java
** Abstract : Base class for all OO 4GL classes (replaces Progress.Lang.Object).
**
** Copyright (c) 2018-2024, Golden Code Development Corporation.
**
** -#- -I- --Date-- --------------------------------------Description---------------------------------------
** 001 GES 20181208 First version.
** 002 CA  20190219 Runtime implementation.
** 003 CA  20190423 4GL's Progress.Lang.Object:equals and toString emits as legacyEquals and
**                  legacyToString, to not collide with Java's Object.equals and toString.
** 004 CA  20190509 Always use <? extends _BaseObject_>.
** 005 CA  20190720 Emit the 'this' reference for the BlockManager APIs.
** 006 CA  20191023 Fixed the LegacySignature.name for legacyEquals method.
**     GES 20191024 Added method support levels and updated the class support level.
** 007 CA  20200330 Fixed legacy ToString method.
**     GES 20200520 Minor NPE protection added.
**     GES 20200603 Moved class registration into a static initializer.
** 008 ME  20210115 Override equals using legacyEquals and hashCode to use resource id (if possible).
**         20210209 Revert changes, removed hashCode/equals method.
** 009 CA  20210221 Fixed 'qualified', 'extent' and 'returns' annotations at the legacy
**                  signature.
**     CA  20220513 Renamed _BaseObject_.clone() to legacyClone(), as it can be overriden by sub-classes and
**                  the access mode may collide with the Java's Object.clone().
** 010 ME  20230829 NextSibling/PrevSibling returns unknown for internal/untracked instances.
** 011 CA  20231113 The 'execute' method must be annotated with LegacySignature Type.Execute, and also can be
**                  dropped if is a no-op.
** 012 CA  20240324 Added a flag to allow tracking the objects valid state without a map lookup.  This flag is
**                  set to false when the instance gets deleted.
** 013 CA  20240918 Removed default methods from interfaces and moved them as concrete implementations, as
**                  default methods cause the Java metaspace to spike one order of magnitude.
*/

/*
** 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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** 
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**     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.oo.lang;

import static com.goldencode.p2j.util.BlockManager.*;
import static com.goldencode.p2j.report.ReportConstants.*;

import com.goldencode.p2j.oo.core.*;
import com.goldencode.p2j.util.*;
import com.goldencode.p2j.util.InternalEntry.Type;

/**
 * Base class for all OO 4GL classes (replaces Progress.Lang.Object). Any change made to the
 * public API of this case must also be present in {@code _BaseObject_}.
 */
@LegacyResource(resource = "Progress.Lang.Object")
@LegacyResourceSupport(supportLvl = CVT_LVL_FULL|RT_LVL_FULL)
public class BaseObject
implements _BaseObject_
{
   static
   {
      ObjectOps.registerClass("Progress.Lang.Object", BaseObject.class);
   }

   /** Flag indicating if this instance is valid or was deleted. */
   private boolean valid = false;
   
   /**
    * Implicit, no parameter, method associated with the implicit legacy constructor for the
    * <code>Progress.Lang.Object</code> class.
    */
   @LegacySignature(type = Type.CONSTRUCTOR)
   @LegacyResourceSupport(supportLvl = CVT_LVL_FULL|RT_LVL_FULL)
   @Override
   public void __lang_BaseObject_constructor__()
   {
      internalProcedure(this, "__lang_BaseObject_constructor__", new Block((Body) () -> 
      {
         // no-op
      }));
   }
   
   /**
    * Reports if the given instance is managed as part of the legacy 4GL object life cycle. This
    * includes reference counting, linking in the SESSION object chain, managed construction and
    * destruction.
    *
    * @return   Always {@code true}.
    */
   @Override
   public boolean isTracked()
   {
      return true;
   }

   /**
    * Get the object's valid state (if it was deleted or not).
    * 
    * @return   See above.
    */
   @Override
   public final boolean __isValidInternal__()
   {
      return valid;
   }

   /**
    * Set the object's valid state (if it was deleted or not).
    * 
    * @param    valid
    *           Flag indicating if this instance is valid or not.
    */
   @Override
   public final void __setValidInternal__(boolean valid)
   {
      this.valid = valid;
   }
   
   /**
    * Obtains the next object instance in the linked list of all existing objects.
    *
    * @return   The next object instance. 
    */
   @LegacySignature(returns = "OBJECT", qualified = "Progress.Lang.Object", type = Type.GETTER, name = "next-sibling")
   @LegacyResourceSupport(supportLvl = CVT_LVL_FULL|RT_LVL_FULL)
   @Override
   public object<? extends _BaseObject_> getNextSibling()
   {
      if (!isTracked()) 
      {
         return new object<>();
      }
      
      ObjectResource ores = ObjectOps.asResource(this);
      handle hres = ores.getNextSibling();
      return hres._isValid() ? new object<>((ObjectResource) hres.get())
                             : new object<>();
   }
   
   /**
    * Obtains the previous object instance in the linked list of all existing objects.
    *
    * @return   The previous object instance. 
    */
   @LegacySignature(returns = "OBJECT", qualified = "Progress.Lang.Object", type = Type.GETTER, name = "prev-sibling")
   @LegacyResourceSupport(supportLvl = CVT_LVL_FULL|RT_LVL_FULL)
   @Override
   public object<? extends _BaseObject_> getPrevSibling()
   {
      if (!isTracked()) 
      {
         return new object<>();
      }
      
      ObjectResource ores = ObjectOps.asResource(this);
      handle hres = ores.getPrevSibling();
      return hres._isValid() ? new object<>((ObjectResource) hres.get())
                             : new object<>();
   }
   
   /**
    * Obtains the class of this object instance.
    *
    * @return   The object's class. 
    */
   @LegacySignature(returns = "OBJECT", qualified = "Progress.Lang.Class", type = Type.METHOD, name = "GetClass")
   @LegacyResourceSupport(supportLvl = CVT_LVL_FULL|RT_LVL_FULL)
   @Override
   public object<? extends LegacyClass> getLegacyClass()
   {
      return new object<>(ObjectOps.getClassInstance(this.getClass()));
   }
   
   /**
    * Check if this reference matches the given one.
    * 
    * @param    other
    *           The other reference.
    * 
    * @return   {@code true} if the other reference is not unknown value and if the reference
    *           is the same as this object's reference.
    */
   @LegacySignature(returns = "LOGICAL", type = Type.METHOD, name = "Equals", parameters = 
   {
      @LegacyParameter(name = "other", type = "OBJECT", mode = "INPUT", qualified="Progress.Lang.Object"),
   })
   @LegacyResourceSupport(supportLvl = CVT_LVL_FULL|RT_LVL_FULL)
   @Override
   public logical legacyEquals(object<? extends _BaseObject_> other)
   {
      return new logical(other != null && !other.isUnknown() && other.ref() == this);
   }
   
   /**
    * Get the string representation for this instance.
    * <p>
    * Although the original method name is {@code toString()}, this version returns a 
    * {@code character} type which would conflict with the {@code java.lang.Object.toString()}
    * version.  For this reason, the name is mapped differently during conversion.
    * 
    * @return   The type's name followed by underscore and its resource ID.
    */
   @LegacySignature(returns = "CHARACTER", type = Type.METHOD, name = "ToString")
   @LegacyResourceSupport(supportLvl = CVT_LVL_FULL|RT_LVL_FULL)
   @Override
   public character toLegacyString()
   {
      object<? extends LegacyClass> ocls = getLegacyClass();
      LegacyClass cls = ocls.ref();
      ocls.setUnknown();
      character name = cls.getTypeName();
      // we can't override Object.toString(), it won't compile
      return new character(name.toStringMessage() + "_" + object.resourceId(new object<>(this)));
   }

   /**
    * No-op implementation for clone.
    * 
    * @return   An unknown object.
    */
   @LegacySignature(returns = "OBJECT", qualified = "Progress.Lang.Object", type = Type.METHOD, name = "Clone")
   @LegacyResourceSupport(supportLvl = CVT_LVL_FULL|RT_LVL_FULL)
   @Override
   public object<? extends _BaseObject_> legacyClone()
   {
      ErrorManager.recordOrThrowError(13444, "Clone method is undefined for the class", 
                                     false, false);
      return new object<>();
   }

   protected static void assertNotNull(object<? extends _BaseObject_> obj, String name)
   {
      Assert.notNull(obj, new character(name));
   }

   protected static void assertNotNull(character str, String name)
   {
      Assert.notNull(str, new character(name));
   }
}