1 package ObjectProperty;
   2 #
   3 # File: ObjectProperty.pm
   4 # Author: Manish Sud <msud@san.rr.com>
   5 #
   6 # Copyright (C) 2024 Manish Sud. All rights reserved.
   7 #
   8 # This file is part of MayaChemTools.
   9 #
  10 # MayaChemTools is free software; you can redistribute it and/or modify it under
  11 # the terms of the GNU Lesser General Public License as published by the Free
  12 # Software Foundation; either version 3 of the License, or (at your option) any
  13 # later version.
  14 #
  15 # MayaChemTools is distributed in the hope that it will be useful, but without
  16 # any warranty; without even the implied warranty of merchantability of fitness
  17 # for a particular purpose.  See the GNU Lesser General Public License for more
  18 # details.
  19 #
  20 # You should have received a copy of the GNU Lesser General Public License
  21 # along with MayaChemTools; if not, see <http://www.gnu.org/licenses/> or
  22 # write to the Free Software Foundation Inc., 59 Temple Place, Suite 330,
  23 # Boston, MA, 02111-1307, USA.
  24 #
  25 
  26 use strict;
  27 use Carp;
  28 
  29 use vars qw($AUTOLOAD);
  30 
  31 # Set property for an object...
  32 sub SetProperty {
  33   my($This, $Name, $Value) = @_;
  34 
  35   if (!(defined($Name) && defined($Value))) {
  36     return undef;
  37   }
  38   return $This->_SetProperty($Name, $Value);
  39 }
  40 
  41 # Set properties for an object...
  42 sub SetProperties {
  43   my($This, %NamesAndValues) = @_;
  44   my($Name, $Value);
  45 
  46   while (($Name, $Value) = each  %NamesAndValues) {
  47     $This->_SetProperty($Name, $Value);
  48   }
  49 
  50   return $This;
  51 }
  52 
  53 # Set object property...
  54 sub _SetProperty {
  55   my($This, $Name, $Value) = @_;
  56 
  57   $This->{$Name} = $Value;
  58 }
  59 
  60 # Get property for an object...
  61 sub GetProperty {
  62   my($This, $Name) = @_;
  63 
  64   if (!defined $Name) {
  65     return undef;
  66   }
  67   return $This->_GetProperty($Name);
  68 }
  69 
  70 # Get object property...
  71 sub _GetProperty {
  72   my($This, $Name) = @_;
  73 
  74   if (exists $This->{$Name}) {
  75     return $This->{$Name};
  76   }
  77   else {
  78     return undef;
  79   }
  80 }
  81 
  82 # Does this property exist?
  83 sub HasProperty {
  84   my($This, $Name) = @_;
  85 
  86   if (!defined $Name) {
  87     return 0;
  88   }
  89   return (exists $This->{$Name}) ? 1 : 0;
  90 }
  91 
  92 # Delete object property...
  93 sub DeleteProperty {
  94   my($This, $Name) = @_;
  95 
  96   if (!defined $Name) {
  97     return undef;
  98   }
  99   return $This->_DeleteProperty($Name);
 100 }
 101 
 102 # Delete object property...
 103 sub _DeleteProperty {
 104   my($This, $Name) = @_;
 105 
 106   if (exists $This->{$Name}) {
 107     delete $This->{$Name};
 108   }
 109   return $This;
 110 }
 111 
 112 # Implements Set<PropertyName> and Get<PropertyName> methods...
 113 sub AUTOLOAD {
 114   my($This, $PropertyValue) = @_;
 115   my($PackageName, $MethodName, $PropertyName, $ThisType);
 116 
 117   # Do a greedy match to make sure package name and method names are
 118   # picked up correctly from invocation names containing multiple occurences
 119   # of ::. For example: FileIO::SDFileIO::GetFileHandle and so on.
 120   #
 121   ($PackageName, $MethodName) = $AUTOLOAD =~ /^(.*)::(.*)$/;
 122 
 123   if ($MethodName =~ /^(BEGIN|DESTROY)$/) {
 124     return;
 125   }
 126 
 127   $ThisType = ref($This) or croak "Error: Invocation of function ${PackageName}::${MethodName} invocation is not supported: It must be invoked using an object reference...";
 128 
 129   if (!($MethodName =~ /^Get/ || $MethodName =~ /^Set/ || $MethodName =~ /^Delete/)) {
 130     croak "Error: Can't locate object method \"$MethodName\" via package \"$ThisType\": This method is not automatically implemented by AUTOLOAD: Only Get<PropertyName>, Set<PropertyName> and Delete<PropertyName> functions are implemented via AUTOLOAD...";
 131   }
 132   if ($MethodName =~ /^Delete/) {
 133     ($PropertyName) = $MethodName =~ /^Delete(.*?)$/;
 134   }
 135   else {
 136     ($PropertyName) = $MethodName =~ /^[SG]et(.*?)$/;
 137   }
 138   if ($MethodName =~ /^Set/ && !defined($PropertyValue)) {
 139     carp "Warning:  ${PackageName}::${MethodName}: Didn't set value for property $PropertyName: Property value for must be specified...\n";
 140     return undef;
 141   }
 142 
 143   if ($MethodName =~ /^Get/) {
 144     return $This->_GetProperty($PropertyName);
 145   }
 146   elsif ($MethodName =~ /^Set/) {
 147     return $This->_SetProperty($PropertyName, $PropertyValue);
 148   }
 149   elsif ($MethodName =~ /^Delete/) {
 150     return $This->_DeleteProperty($PropertyName);
 151   }
 152 
 153 }
 154