DeferredProgramWrapper.java

/*
** Module   : DeferredProgramWrapper.java
** Abstract : Implements the deferred program resource, for SINGLE-RUN or SINGLETON modes.
**
** Copyright (c) 2019-2023, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------Description----------------------------------
** 001 CA  20190628 Created initial version.
** 002 AIL 20200622 Made use of the new procedure delete signature.
**                  Changed the behavior of multiple deletes when there is a server instance.
** 003 ME  20201203 Internal entries is unknown for 'proxy' procedures.
** 004 CA  20230110 Cache the helper for ProcedureManager, ObjectOps and others (as needed), to reduce  
**                  context-local lookup.
*/
/*
** 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.
** 
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** 
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*/

package com.goldencode.p2j.util;

import com.goldencode.p2j.util.ProcedureManager.SearchMode;

/**
 * This program represents the instance used to assign to a handle, when a statement like
 * <code>RUN ... {SINGLETON|SINGLE-RUN} SET h</code> is executed.
 * <p>
 * This saves a {@link DeferredProgram} instance, with the details of the program to be ran, when
 * one if its internal-entries (or methods, for legacy classes) is accessed.
 */
public class DeferredProgramWrapper
extends ExternalProgramWrapper
{
   /**
    * Create a new wrapper.
    * 
    * @param    deferred
    *           The configuration to defer this invocation.
    */
   public DeferredProgramWrapper(DeferredProgram deferred)
   {
      super(deferred);
   }

   /**
    * Get the <code>persistent</code> attribute of this instance.
    * 
    * @return   Always <code>false</code>. 
    */
   public logical isPersistent()
   {
      return new logical(false);
   }
   
   /**
    * Get the <code>INTERNAL-ENTRIES</code> attribute of this instance.
    * 
    * @return   Always empty string.
    */
   public character internalEntries()
   {
      return new character();
   }

   /**
    * Execute the <code>GET-SIGNATURE</code> method of this instance.
    * 
    * @param    internalEntry
    *           The legacy name of the internal-entry for which the signature is needed.
    * 
    * @return   Always empty string.
    */
   public character getSignature(character internalEntry)
   {
      return new character("");
   }

   /**
    * Get the <code>SUPER-PROCEDURES</code> attribute of this instance.
    * 
    * @return   Always empty string.
    */
   public character superProcedures()
   {
      return new character("");
   }

   /**
    * Add the given handle as a super-procedure for the current handle.
    * 
    * @param    h
    *           The handle to be added as a super-procedure.
    *           
    * @return   Always <code>false</code>.
    */
   public logical addSuperProcedure(handle h)
   {
      return new logical(false);
   }

   /**
    * Add the given handle as a super-procedure for the current handle, using
    * the explicit {@link SearchMode mode}.
    * 
    * @param    h
    *           The handle to be added as a super-procedure.
    * @param    mode
    *           The {@link SearchMode} to be set for the <code>h</code> handle.
    *           
    * @return   Always <code>false</code>.
    */
   public logical addSuperProcedure(handle h, SearchMode mode)
   {
      return new logical(false);
   }

   /**
    * Add the given handle as a super-procedure for the current handle, using
    * the search-mode set as a string (one of the <code>SEARCH-TARGET</code>
    * or <code>SEARCH-SELF</code> string literals).
    * 
    * @param    h
    *           The handle to be added as a super-procedure.
    * @param    mode
    *           The search-mode to be set for the <code>h</code> handle.
    *           
    * @return   Always <code>false</code>.
    */
   public logical addSuperProcedure(handle h, int mode)
   {
      return new logical(false);
   }

   /**
    * Add the given handle as a super-procedure for the current handle, using
    * the search-mode set as a string (one of the <code>SEARCH-TARGET</code>
    * or <code>SEARCH-SELF</code> string literals).
    * 
    * @param    h
    *           The handle to be added as a super-procedure.
    * @param    mode
    *           The search-mode to be set for the <code>h</code> handle.
    *           
    * @return   Always <code>false</code>.
    */
   public logical addSuperProcedure(handle h, integer mode)
   {
      return new logical(false);
   }

   /**
    * Remove the given handle from this handle's list of super-procedures.
    *  
    * @param    h
    *           The procedure handle to be removed.
    *           
    * @return   Always <code>false</code>.
    */
   public logical removeSuperProcedure(handle h)
   {
      return new logical(false);
   }

   /**
    * Indicates if the procedure is a proxy procedure.
    * 
    * @return   always <code>true</code>
    */
   public logical isProxy()
   {
      return new logical(true);
   }
   
   /**
    * Get the named events published by this procedure.
    * 
    * @return    Always empty string.
    */
   @Override
   public character getPublishedEvents()
   {
      return new character("");
   }

   /**
    * Get the <code>NEXT-SIBLING</code> attribute of this instance.
    * 
    * @return   Always an unknown value.
    */
   public handle getNextSibling()
   {
      return new handle();
   }

   /**
    * Get the <code>PREV-SIBLING</code> attribute of this instance.
    * 
    * @return   Always an unknown value.
    */
   public handle getPrevSibling()
   {
      return new handle();
   }

   /**
    * Perform actual delete of this procedure, by calling {@link ProcedureManager#delete(Object, boolean)}.
    */
   public void delete()
   {
      if (pm.delete(this.get(), ((DeferredProgram) referent).getServer() == null))
      {
         // cleanup after it
         handle.removeResource(this);
      }
   }
   
   /**
    * A deferred program wrapper is eligible for multiple deletes only if there is no server instance.
    */
   @Override
   public boolean handleMultipleDeletes()
   {
      return ((DeferredProgram) referent).getServer() == null;
   }
}