# TriggerDefinition.java

    /*
    ** Module   : TriggerDefinition.java
    ** Abstract : container for trigger metadata that allows a new instance to
    **            be manufactured
    **
    ** Copyright (c) 2008-2023, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- --JPRM-- -----------------------------Description-----------------------------
    ** 001 GES 20081217   @40928 Created initial version as the container for trigger metadata that
    **                           allows a new instance to be manufactured.
    ** 002 CA  20140218          Expose trigger's external program instance.
    ** 003 CA  20151030          Report if the trigger definition was created in an external program.
    ** 004 GES 20161004          Enabled an alternate path that uses a single pre-instantiated
    **                           Trigger instance (using lambdas).  Inner class mode is still
    **                           supported and is needed when there are local variables defined for
    **                           the trigger.
    ** 005 CA  20190328          Triggers are emitted as anon inner classes, instantiated via a lambda
    **                           expression.
    ** 006 GBB 20230512          Logging methods replaced by CentralLogger/ConversionStatus.
    */
    /*
    ** 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
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    **     attribution required in this license.
    */

    package com.goldencode.p2j.util;

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

    import java.util.function.*;

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

    /**
     * Container for trigger metadata that allows a new instance to be
     * manufactured.
     * <p>
     * Triggers are anonymous inner classes that may have data members. The
     * initialization of those data members naturally occurs during construction.
     * This means that only after construction can one be assured that the value
     * of a trigger's data members is set to the expected default value. This
     * means that every time a trigger is executed, that execution must occur on
     * a newly constructed instance, so that the data member's default values
     * will be correct.
     * <p>
     * This class stores the data needed to delegate the construction of a
     * {@link Trigger} subclass to code that is executing that trigger. This is
     * performed via a lambda expression, which creates a new instance of the
     * trigger each time the trigger is invoked.
     * <p>
     * The complexity of the instantiation is hidden in this class. The logic
     * can be found in {@link #getTrigger}.
     */
    public class TriggerDefinition
    {
       /** Logger (this is JVM-wide rather than being context-local). */
       private static final CentralLogger LOG =
          CentralLogger.get(TransactionManager.class.getName());

       /** The supplier for this trigger's instances. */
       private Supplier<Trigger> trigger = null;

       /** The external program instance where the trigger was defined. */
       private Object externalProgram = null;

       /** Determines if this trigger should start a full transaction. */
       private boolean fullTrans = false;

       /** Flag indicating the trigger definition was created in an external program. */
       private final boolean fromExternalProgram;

       /**
        * Constructor for lambda mode.
        *
        * @param    trigger
        *           The specific {@link Trigger} instance that implements the
        *           trigger logic.
        * @param    outer
        *           The instance of the containing class for the trigger.
        * @param    fullTrans
        *           <code>true</code> if the trigger should start a full
        *           transaction, <code>false</code> if the trigger should
        *           create a sub-transaction.
        */
       public TriggerDefinition(Supplier<Trigger> trigger, Object outer, boolean fullTrans)
       {
          this.trigger   = trigger;
          this.fullTrans = fullTrans;
          this.externalProgram = outer;
          this.fromExternalProgram = TransactionManager.isExternalBlock();
          this.fullTrans = fullTrans;
       }

       /**
        * Construct a new instance of the trigger class that is defined by the
        * contained metadata.
        *
        * @return   The newly instantiated trigger instance. If any failure
        *           occurs, this will return <code>null</code>.
        */
       public Trigger getTrigger()
       {
          Trigger instance = trigger.get();
          if (fullTrans)
          {
             instance.setLevel(TransactionType.FULL);
          }

          return instance;
       }

       /**
        * Get the external program instance where this trigger was defined.
        *
        * @return    See above.
        */
       public Object getExternalProgram()
       {
          return externalProgram;
       }

       /**
        * Check if this trigger was created by an external program.
        *
        * @return   The state of the {@link #fromExternalProgram} flag.
        */
       public boolean isFromExternalProgram()
       {
          return fromExternalProgram;
       }
    }