ComhandlePropertyRef.java

/*
** Module   : ComhandlePropertyRef.java
** Abstract : Data wrapper which associates with a legacy OO property and provides direct access 
**            to this property.
**
** Copyright (c) 2019, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------Description----------------------------------
** 001 CA  20190524 Created initial version.
** 002 CA  20190604 Fixed javadocs.
*/
/*
** 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
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**     name Golden Code, FWD, or the names of any author or contributor, for
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**     the covered work, without written authorization.
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*/

package com.goldencode.p2j.util;

import com.goldencode.p2j.comauto.*;
import com.goldencode.p2j.oo.lang.*;

/**
 * Data wrapper which associates with a OO property and provides direct access to this property.
 * <p>
 * All writing is done to both the OO member and the local {@link comhandle}'s private {@code value}.
 * On instantiation, the current property value is saved in the {@link comhandle}'s private 
 * {@code value}, and this instance will be used for reading until {@link #assign} or 
 * {@link #setUnknown} is called again.
 */
public class ComhandlePropertyRef
extends comhandle
{
   /** The property referenced by this instance. */
   private final PropertyReference propertyRef;
   
   /**
    * Constructor.
    * 
    * @param   className
    *          The class name in case of static property access.
    * @param   property
    *          Name of class property member.
    */
   public ComhandlePropertyRef(String className, String property)
   {
      this.propertyRef = new PropertyReference(className, property);
      
      init(null);
   }
   
   /**
    * Constructor.
    * 
    * @param   instance
    *          The class instance, for instance property access.
    * @param   property
    *          Name of class property member.
    */
   public ComhandlePropertyRef(object<? extends _BaseObject_> instance, String property)
   {
      this.propertyRef = new PropertyReference(instance, property);
      
      init(instance);
   }
   
   /**
    * Constructor.
    * 
    * @param   className
    *          The class name in case of static property access.
    * @param   property
    *          Name of class property member.
    * @param   index
    *          Index to pass to property's getter method at resolve time.
    */
   public ComhandlePropertyRef(String className, String property, int64 index)
   {
      this.propertyRef = new PropertyReference(className, property, index);
      
      init(null);
   }
   
   /**
    * Constructor.
    * 
    * @param   className
    *          The class name in case of static property access.
    * @param   property
    *          Name of class property member.
    * @param   index
    *          Index to pass to property's getter method at resolve time.
    */
   public ComhandlePropertyRef(String className, String property, int index)
   {
      this.propertyRef = new PropertyReference(className, property, index);
      
      init(null);
   }
   
   /**
    * Constructor.
    * 
    * @param   instance
    *          The class instance, for instance property access.
    * @param   property
    *          Name of class property member.
    * @param   index
    *          Index to pass to property's getter method at resolve time.
    */
   public ComhandlePropertyRef(object<? extends _BaseObject_> instance, String property, int64 index)
   {
      this.propertyRef = new PropertyReference(instance, property, index);
      
      init(instance);
   }
   
   /**
    * Constructor.
    * 
    * @param   instance
    *          The class instance, for instance property access.
    * @param   property
    *          Name of class property member.
    * @param   index
    *          Index to pass to property's getter method at resolve time.
    */
   public ComhandlePropertyRef(object<? extends _BaseObject_> instance, String property, int index)
   {
      this.propertyRef = new PropertyReference(instance, property, index);
      
      init(instance);
   }

   /**
    * Dedicated assignment method for loading a {@code ComObject} into this {@code comhandle}.
    * This method is only called by {@link com.goldencode.p2j.comauto.ComServer#create}. Stores 
    * a newly created {@code ComObject} into this handle.
    * <p>
    * Also updates the {@link #propertyRef} with the new state of this comhandle instance.
    * 
    * @param   newVal
    *          The new value to be stored by this handle. 
    */
   @Override
   public void assign(ComObject newVal)
   {
      super.assign(newVal);
      
      propertyRef.set(this);
   }
   
   /**
    * Sets the state (data and unknown value) of this instance based on the state of the passed
    * instance.
    * <p>
    * Also updates the {@link #propertyRef} with the new state of this comhandle instance.
    *
    * @param    value
    *           The instance from which to copy state.
    */
   @Override
   public void assign(BaseDataType value)
   {
      super.assign(value);
      
      propertyRef.set(this);
   }

   /**
    * Sets the state of this instance's <code>unknown value</code> flag or state to <code>true</code>.
    * <p>
    * <b>Warning: the data stored in this instance may be invalid after calling this method.</b>
    * <p>
    * Also updates the {@link #propertyRef} with the new state of this handle instance.
    */
   public void setUnknown()
   {
      super.setUnknown();
      
      propertyRef.set(this);
   }

   /**
    * Initialize this instance.
    * 
    * @param    instance
    *           non-null for instance property member.
    */
   private void init(object<? extends _BaseObject_> instance)
   {
      if (instance == null || !instance.isUnknown())
      {
         super.assign((comhandle) propertyRef.get());
      }
      else
      {
         super.setUnknown();
      }
   }
}