Storage/Handler/Abstract.pm

#################################
#
#  $Id: Abstract.pm,v 1.3 2002/11/29 04:58:20 joko Exp $
#
#  $Log: Abstract.pm,v $
#  Revision 1.3  2002/11/29 04:58:20  joko
#  + Storage::Result now uses the same dispatching mechanism like Storage::Handler
#
#  Revision 1.2  2002/10/17 00:08:07  joko
#  + bugfixes regarding "deep recursion" stuff
#
#  Revision 1.1  2002/10/10 03:44:07  cvsjoko
#  + new
#
#
#################################

package Data::Storage::Handler::Abstract;

use strict;
use warnings;

use Data::Dumper;

# get logger instance
my $logger = Log::Dispatch::Config->instance;

#our $lock_info;

sub new {
  my $invocant = shift;
  my $class = ref($invocant) || $invocant;
  
  # logging info about the actual handler called
    $logger->debug( "$invocant->new( @_ )" );
    #$logger->debug( __PACKAGE__ . "->" . "new()" );

  # arguments become properties
  my $self = { @_ };
  # create object from blessed hash-reference
  bless $self, $class;

  # handle meta data
    #my $metainfo = $self->getMetaInfo($class);
    my $metainfo = $self->getMetaInfo();
    if (!$metainfo->{disconnectMethod}) { $metainfo->{disconnectMethod} = 'disconnect'; }
    # type?
    $invocant =~ s/Data::Storage::Handler:://;
    $metainfo->{type} = $invocant;

    # direct accessible (non-protected) properties         ( was: my $self = { }; )
    $self->{metainfo} = $metainfo;

  return $self;
}


sub AUTOLOAD {

  # recursion problem to be avoided here!!!
  
    # - problem: we get recursion-hangs!!!   =>  perl stops with ...
    # "Deep recursion on subroutine "Data::Storage::Handler::Abstract::AUTOLOAD" at [...]/libs/Data/Storage.pm line 38."
    
    # - when: if we log to ourselves as a storage-implementation (e.g. via Log::Dispatch::Tangram)
    # - why:  debug-messages are on a very low level including every data-operation to "Data::Storage(::Handler::X)",
    #             so e.g. a "$storage->insert" would trigger another "$storage->insert" itself 
    #             which leads to a infinite recursion loop (deep recursion)
    # - solution: locks! (by Hack or (maybe) via Perl "local"s)

  my $self = shift;

  our $AUTOLOAD;
  #return if $AUTOLOAD =~ m/::DESTROY$/;

  # find out methodname
  my $methodname = $AUTOLOAD;
  $methodname =~ s/^.*:://;

  # handle locking (hack)
  if ($self->{lock_info}->{last_method} && $methodname eq $self->{lock_info}->{last_method}) {
    $self->{lock_info}->{log_lock} = 1;
  } else {
    $self->{lock_info}->{log_lock} = 0;
  }
  $self->{lock_info}->{last_method} = $methodname;
  
  # test for COREHANDLE
  if (!$self->{COREHANDLE}) {
    #print "no COREHANDLE", "\n";
    if (!$self->{lock_info}->{log_lock}) {
      $logger->error( __PACKAGE__ . "[$self->{metainfo}->{type}]" . ": " . "COREHANDLE is undefined while trying to execute method \"$methodname\"" );
    }
    return;
  }

  # try to dispatch method-call to Storage::Handler::*
  #if ($self->can($methodname)) {
    #$logger->debug( __PACKAGE__ . "[$self->{metainfo}->{type}]" . "->" . $methodname . "(@_)" );
    #my $res = $self->$methodname(@_);
    #if ($res) { return $res; }
  #}

  # try to dispatch method-call to COREHANDLE
  if ($self->{COREHANDLE}->can($methodname) || $self->{COREHANDLE}->can("AUTOLOAD")) {
    #$logger->debug( __PACKAGE__ . "->" . $methodname . " (AUTOLOAD)" );
    #$lock_AUTOLOAD = 1 if ($methodname eq 'insert');
    if (!$self->{lock_info}->{log_lock}) {
      #print "method: $methodname", "\n";
      $logger->debug( __PACKAGE__ . "[$self->{metainfo}->{type}]" . "->" . $methodname . "(@_)" );
    } else {
      # AUTOLOAD - sub is locked to prevent deep recursions if (e.g.) db-inserts cause log-actions to same db itself
    }
    #$lock_AUTOLOAD = 0;
    #$logger->log( level => 'debug', message => __PACKAGE__ . "->" . $methodname . " (AUTOLOAD)" );
    
    # method calls doing it until here will get dispatched to the proper handler
    return $self->{COREHANDLE}->$methodname(@_);
  }

}

sub DESTROY {
  my $self = shift;
  if ($self->{COREHANDLE}) {
    $logger->debug( __PACKAGE__ . "[$self->{metainfo}->{type}]" . "->DESTROY" );

    my $disconnectMethod = $self->{metainfo}->{disconnectMethod};

    # call "disconnect" or alike on COREHANDLE
    # was: $self->{COREHANDLE}->disconnect();
    $disconnectMethod && ( $self->{COREHANDLE}->$disconnectMethod() );

    undef $self->{COREHANDLE};
  }
}


sub _abstract_function {
  my $self = shift;
  my $fName = shift;
  my $class = ref($self);
  $logger->error( __PACKAGE__ . ": function \"$fName\" is an abstract method, please implement it in \"$class\"");
  #exit;
}

sub _typeCheck {
  my $type = shift;
  print "type: $type";
  eval("use Data::Storage::$type;");
}


# ====================================================
#   PUBLIC METHODS
# ====================================================

  sub existsChildNode {
    my $self = shift;
    my $nodename = shift;
    #$nodename = 'TransactionRoutingTable';
    $logger->debug( __PACKAGE__ . "->getChildNode( nodename $nodename )" );
    $self->getChildNodes() unless $self->{meta}->{childnodes};
    my $result = grep(m/$nodename/i, @{$self->{meta}->{childnodes}});     # TODO: use "/i" only on win32-systems!
    return $result;
  }

  sub connect_tmp {
    
#    my $self = shift;
#    my $connectionString = shift;
#    # todo: patch connectionString to $args
#    _typeCheck($self->{args}{type});

  }
  

# ====================================================
#   CONCRETE METHOD DUMMIES (croaking via "$logger" by calling "_abstract_function")
# ====================================================

  # TODO:
  #   - abstract "abstract methods" to list/hash to be used in AUTOLOAD
  #      e.g.: my @ABSTRACT_METHODS = (qw( connect sendCommand getChildNodes ));
  #      use Class::XYZ (Construct)
  #   - build them via anonymous subs 
  #   - introduce them via symbols

  sub sendCommand {
    my $self = shift;
    $self->_abstract_function('sendCommand');
  }

  sub getChildNodes {
    my $self = shift;
    $self->_abstract_function('getChildNodes');
  }

  sub configureCOREHANDLE {
    my $self = shift;
    $self->_abstract_function('configureCOREHANDLE');
  }

  sub getMetaInfo {
    my $self = shift;
    $self->_abstract_function('getMetaInfo');
    return;
  }

  sub getListUnfiltered {
    my $self = shift;
    $self->_abstract_function('getListUnfiltered');
    return;
  }

  sub getListFiltered {
    my $self = shift;
    $self->_abstract_function('getListFiltered');
    return;
  }

  sub sendQuery {
    my $self = shift;
    $self->_abstract_function('sendQuery');
    return;
  }

  sub connect {
    my $self = shift;
    $self->_abstract_function('connect');
    return;
  }

  sub testIntegrity {
    my $self = shift;
    $self->_abstract_function('testIntegrity');
    return;
  }

  sub quoteSql {
    my $self = shift;
    $self->_abstract_function('quoteSql');
    return;
  }

  sub eraseAll {
    my $self = shift;
    $self->_abstract_function('eraseAll');
    return;
  }

  sub createDb {
    my $self = shift;
    $self->_abstract_function('createDb');
    return;
  }

1;
1	cvsjoko	1.1	#################################
2			#
3	joko	1.4	# $Id: Abstract.pm,v 1.3 2002/11/29 04:58:20 joko Exp $
4	joko	1.2	#
5			# $Log: Abstract.pm,v $
6	joko	1.4	# Revision 1.3 2002/11/29 04:58:20 joko
7			# + Storage::Result now uses the same dispatching mechanism like Storage::Handler
8			#
9	joko	1.3	# Revision 1.2 2002/10/17 00:08:07 joko
10			# + bugfixes regarding "deep recursion" stuff
11			#
12	joko	1.2	# Revision 1.1 2002/10/10 03:44:07 cvsjoko
13			# + new
14	cvsjoko	1.1	#
15			#
16			#################################
17
18			package Data::Storage::Handler::Abstract;
19
20			use strict;
21			use warnings;
22
23			use Data::Dumper;
24
25			# get logger instance
26			my $logger = Log::Dispatch::Config->instance;
27
28			#our $lock_info;
29
30			sub new {
31			my $invocant = shift;
32			my $class = ref($invocant) \|\| $invocant;
33
34			# logging info about the actual handler called
35			$logger->debug( "$invocant->new( @_ )" );
36	joko	1.2	#$logger->debug( __PACKAGE__ . "->" . "new()" );
37	cvsjoko	1.1
38	joko	1.3	# arguments become properties
39			my $self = { @_ };
40			# create object from blessed hash-reference
41			bless $self, $class;
42
43	cvsjoko	1.1	# handle meta data
44	joko	1.3	#my $metainfo = $self->getMetaInfo($class);
45			my $metainfo = $self->getMetaInfo();
46	cvsjoko	1.1	if (!$metainfo->{disconnectMethod}) { $metainfo->{disconnectMethod} = 'disconnect'; }
47			# type?
48			$invocant =~ s/Data::Storage::Handler:://;
49			$metainfo->{type} = $invocant;
50
51			# direct accessible (non-protected) properties ( was: my $self = { }; )
52	joko	1.3	$self->{metainfo} = $metainfo;
53	cvsjoko	1.1
54			return $self;
55			}
56
57
58			sub AUTOLOAD {
59
60			# recursion problem to be avoided here!!!
61
62			# - problem: we get recursion-hangs!!! => perl stops with ...
63			# "Deep recursion on subroutine "Data::Storage::Handler::Abstract::AUTOLOAD" at [...]/libs/Data/Storage.pm line 38."
64
65			# - when: if we log to ourselves as a storage-implementation (e.g. via Log::Dispatch::Tangram)
66			# - why: debug-messages are on a very low level including every data-operation to "Data::Storage(::Handler::X)",
67			# so e.g. a "$storage->insert" would trigger another "$storage->insert" itself
68			# which leads to a infinite recursion loop (deep recursion)
69	joko	1.2	# - solution: locks! (by Hack or (maybe) via Perl "local"s)
70	cvsjoko	1.1
71			my $self = shift;
72
73			our $AUTOLOAD;
74			#return if $AUTOLOAD =~ m/::DESTROY$/;
75
76			# find out methodname
77			my $methodname = $AUTOLOAD;
78			$methodname =~ s/^.*:://;
79
80			# handle locking (hack)
81			if ($self->{lock_info}->{last_method} && $methodname eq $self->{lock_info}->{last_method}) {
82			$self->{lock_info}->{log_lock} = 1;
83			} else {
84			$self->{lock_info}->{log_lock} = 0;
85			}
86			$self->{lock_info}->{last_method} = $methodname;
87
88			# test for COREHANDLE
89			if (!$self->{COREHANDLE}) {
90	joko	1.2	#print "no COREHANDLE", "\n";
91			if (!$self->{lock_info}->{log_lock}) {
92			$logger->error( __PACKAGE__ . "[$self->{metainfo}->{type}]" . ": " . "COREHANDLE is undefined while trying to execute method \"$methodname\"" );
93			}
94	cvsjoko	1.1	return;
95			}
96
97			# try to dispatch method-call to Storage::Handler::*
98			#if ($self->can($methodname)) {
99			#$logger->debug( __PACKAGE__ . "[$self->{metainfo}->{type}]" . "->" . $methodname . "(@_)" );
100			#my $res = $self->$methodname(@_);
101			#if ($res) { return $res; }
102			#}
103
104			# try to dispatch method-call to COREHANDLE
105			if ($self->{COREHANDLE}->can($methodname) \|\| $self->{COREHANDLE}->can("AUTOLOAD")) {
106			#$logger->debug( __PACKAGE__ . "->" . $methodname . " (AUTOLOAD)" );
107			#$lock_AUTOLOAD = 1 if ($methodname eq 'insert');
108			if (!$self->{lock_info}->{log_lock}) {
109			#print "method: $methodname", "\n";
110			$logger->debug( __PACKAGE__ . "[$self->{metainfo}->{type}]" . "->" . $methodname . "(@_)" );
111			} else {
112			# AUTOLOAD - sub is locked to prevent deep recursions if (e.g.) db-inserts cause log-actions to same db itself
113			}
114			#$lock_AUTOLOAD = 0;
115			#$logger->log( level => 'debug', message => __PACKAGE__ . "->" . $methodname . " (AUTOLOAD)" );
116	joko	1.3
117			# method calls doing it until here will get dispatched to the proper handler
118	cvsjoko	1.1	return $self->{COREHANDLE}->$methodname(@_);
119			}
120
121			}
122
123			sub DESTROY {
124			my $self = shift;
125			if ($self->{COREHANDLE}) {
126			$logger->debug( __PACKAGE__ . "[$self->{metainfo}->{type}]" . "->DESTROY" );
127
128			my $disconnectMethod = $self->{metainfo}->{disconnectMethod};
129
130			# call "disconnect" or alike on COREHANDLE
131			# was: $self->{COREHANDLE}->disconnect();
132			$disconnectMethod && ( $self->{COREHANDLE}->$disconnectMethod() );
133
134			undef $self->{COREHANDLE};
135			}
136			}
137
138
139			sub _abstract_function {
140			my $self = shift;
141			my $fName = shift;
142			my $class = ref($self);
143			$logger->error( __PACKAGE__ . ": function \"$fName\" is an abstract method, please implement it in \"$class\"");
144			#exit;
145			}
146
147			sub _typeCheck {
148			my $type = shift;
149			print "type: $type";
150			eval("use Data::Storage::$type;");
151			}
152
153
154			# ====================================================
155			# PUBLIC METHODS
156			# ====================================================
157
158	joko	1.3	sub existsChildNode {
159			my $self = shift;
160			my $nodename = shift;
161			#$nodename = 'TransactionRoutingTable';
162			$logger->debug( __PACKAGE__ . "->getChildNode( nodename $nodename )" );
163			$self->getChildNodes() unless $self->{meta}->{childnodes};
164			my $result = grep(m/$nodename/i, @{$self->{meta}->{childnodes}}); # TODO: use "/i" only on win32-systems!
165			return $result;
166			}
167	cvsjoko	1.1
168	joko	1.3	sub connect_tmp {
169	cvsjoko	1.1
170			# my $self = shift;
171			# my $connectionString = shift;
172			# # todo: patch connectionString to $args
173			# _typeCheck($self->{args}{type});
174
175			}
176
177	joko	1.3
178			# ====================================================
179			# CONCRETE METHOD DUMMIES (croaking via "$logger" by calling "_abstract_function")
180			# ====================================================
181
182			# TODO:
183			# - abstract "abstract methods" to list/hash to be used in AUTOLOAD
184			# e.g.: my @ABSTRACT_METHODS = (qw( connect sendCommand getChildNodes ));
185	joko	1.4	# use Class::XYZ (Construct)
186	joko	1.3	# - build them via anonymous subs
187			# - introduce them via symbols
188
189	cvsjoko	1.1	sub sendCommand {
190			my $self = shift;
191			$self->_abstract_function('sendCommand');
192			}
193
194			sub getChildNodes {
195			my $self = shift;
196			$self->_abstract_function('getChildNodes');
197			}
198
199			sub configureCOREHANDLE {
200			my $self = shift;
201			$self->_abstract_function('configureCOREHANDLE');
202			}
203
204	joko	1.3	sub getMetaInfo {
205			my $self = shift;
206			$self->_abstract_function('getMetaInfo');
207			return;
208			}
209
210			sub getListUnfiltered {
211			my $self = shift;
212			$self->_abstract_function('getListUnfiltered');
213			return;
214			}
215
216			sub getListFiltered {
217			my $self = shift;
218			$self->_abstract_function('getListFiltered');
219			return;
220			}
221
222			sub sendQuery {
223			my $self = shift;
224			$self->_abstract_function('sendQuery');
225			return;
226			}
227
228			sub connect {
229			my $self = shift;
230			$self->_abstract_function('connect');
231			return;
232			}
233
234			sub testIntegrity {
235			my $self = shift;
236			$self->_abstract_function('testIntegrity');
237			return;
238			}
239
240			sub quoteSql {
241			my $self = shift;
242			$self->_abstract_function('quoteSql');
243	joko	1.4	return;
244			}
245
246			sub eraseAll {
247			my $self = shift;
248			$self->_abstract_function('eraseAll');
249			return;
250			}
251
252			sub createDb {
253			my $self = shift;
254			$self->_abstract_function('createDb');
255	joko	1.3	return;
256			}
257
258			1;
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