Storage/Handler/Abstract.pm

#################################
#
#  $Id$
#
#  $Log$
#
#################################

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( __PACKAGE__ . "->" . "new()" );
    $logger->debug( "$invocant->new( @_ )" );

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

  # create object from blessed hash-reference
    # direct accessible (non-protected) properties         ( was: my $self = { }; )
    my $self = { metainfo => $metainfo, @_ };
    bless $self, $class;

  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 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}) {
    $logger->error( __PACKAGE__ . "[$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)" );
    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;");
}

sub _getMetaInfo {
  my $packagename = shift;
  #return $self->$metainfo;

  my $ns = '$' . $packagename . "::metainfo";
  $logger->debug( __PACKAGE__ . "->" . "_getMetaInfo()" . "   " . "[$ns]" );
  return eval($ns);
}


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

  # TODO: abstract "abstract methods" to list/hash to be used in AUTOLOAD
  # e.g.: my @ABSTRACT_METHODS = (qw( connect sendCommand getChildNodes ));

  sub connect {
    
    my $self = shift;
    $self->_abstract_function('connect');
    return;
    
    $logger->debug( "\"connect\" has to be implemented by handler!" );
    return;
    
#    my $self = shift;
#    my $connectionString = shift;
#    # todo: patch connectionString to $args
#    _typeCheck($self->{args}{type});

  }
  
  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');
  }

1;
1	cvsjoko	1.1	#################################
2			#
3			# $Id$
4			#
5			# $Log$
6			#
7			#################################
8
9			package Data::Storage::Handler::Abstract;
10
11			use strict;
12			use warnings;
13
14			use Data::Dumper;
15
16			# get logger instance
17			my $logger = Log::Dispatch::Config->instance;
18
19			#our $lock_info;
20
21			sub new {
22			my $invocant = shift;
23			my $class = ref($invocant) \|\| $invocant;
24
25			# logging info about the actual handler called
26			$logger->debug( __PACKAGE__ . "->" . "new()" );
27			$logger->debug( "$invocant->new( @_ )" );
28
29			# handle meta data
30			my $metainfo = _getMetaInfo($class);
31			if (!$metainfo->{disconnectMethod}) { $metainfo->{disconnectMethod} = 'disconnect'; }
32			# type?
33			$invocant =~ s/Data::Storage::Handler:://;
34			$metainfo->{type} = $invocant;
35
36			# create object from blessed hash-reference
37			# direct accessible (non-protected) properties ( was: my $self = { }; )
38			my $self = { metainfo => $metainfo, @_ };
39			bless $self, $class;
40
41			return $self;
42			}
43
44
45			sub AUTOLOAD {
46
47			# recursion problem to be avoided here!!!
48
49			# - problem: we get recursion-hangs!!! => perl stops with ...
50			# "Deep recursion on subroutine "Data::Storage::Handler::Abstract::AUTOLOAD" at [...]/libs/Data/Storage.pm line 38."
51
52			# - when: if we log to ourselves as a storage-implementation (e.g. via Log::Dispatch::Tangram)
53			# - why: debug-messages are on a very low level including every data-operation to "Data::Storage(::Handler::X)",
54			# so e.g. a "$storage->insert" would trigger another "$storage->insert" itself
55			# which leads to a infinite recursion loop (deep recursion)
56			# - solution: locks! (by Hack or via Perl "local"s)
57
58			my $self = shift;
59
60			our $AUTOLOAD;
61			#return if $AUTOLOAD =~ m/::DESTROY$/;
62
63			# find out methodname
64			my $methodname = $AUTOLOAD;
65			$methodname =~ s/^.*:://;
66
67			# handle locking (hack)
68			if ($self->{lock_info}->{last_method} && $methodname eq $self->{lock_info}->{last_method}) {
69			$self->{lock_info}->{log_lock} = 1;
70			} else {
71			$self->{lock_info}->{log_lock} = 0;
72			}
73			$self->{lock_info}->{last_method} = $methodname;
74
75			# test for COREHANDLE
76			if (!$self->{COREHANDLE}) {
77			$logger->error( __PACKAGE__ . "[$self->{metainfo}->{type}]" . ": " . "COREHANDLE is undefined while trying to execute method \"$methodname\"" );
78			return;
79			}
80
81			# try to dispatch method-call to Storage::Handler::*
82			#if ($self->can($methodname)) {
83			#$logger->debug( __PACKAGE__ . "[$self->{metainfo}->{type}]" . "->" . $methodname . "(@_)" );
84			#my $res = $self->$methodname(@_);
85			#if ($res) { return $res; }
86			#}
87
88			# try to dispatch method-call to COREHANDLE
89			if ($self->{COREHANDLE}->can($methodname) \|\| $self->{COREHANDLE}->can("AUTOLOAD")) {
90			#$logger->debug( __PACKAGE__ . "->" . $methodname . " (AUTOLOAD)" );
91			#$lock_AUTOLOAD = 1 if ($methodname eq 'insert');
92			if (!$self->{lock_info}->{log_lock}) {
93			#print "method: $methodname", "\n";
94			$logger->debug( __PACKAGE__ . "[$self->{metainfo}->{type}]" . "->" . $methodname . "(@_)" );
95			} else {
96			# AUTOLOAD - sub is locked to prevent deep recursions if (e.g.) db-inserts cause log-actions to same db itself
97			}
98			#$lock_AUTOLOAD = 0;
99			#$logger->log( level => 'debug', message => __PACKAGE__ . "->" . $methodname . " (AUTOLOAD)" );
100			return $self->{COREHANDLE}->$methodname(@_);
101			}
102
103			}
104
105			sub DESTROY {
106			my $self = shift;
107			if ($self->{COREHANDLE}) {
108			$logger->debug( __PACKAGE__ . "[$self->{metainfo}->{type}]" . "->DESTROY" );
109
110			my $disconnectMethod = $self->{metainfo}->{disconnectMethod};
111
112			# call "disconnect" or alike on COREHANDLE
113			# was: $self->{COREHANDLE}->disconnect();
114			$disconnectMethod && ( $self->{COREHANDLE}->$disconnectMethod() );
115
116			undef $self->{COREHANDLE};
117			}
118			}
119
120
121			sub _abstract_function {
122			my $self = shift;
123			my $fName = shift;
124			my $class = ref($self);
125			$logger->error( __PACKAGE__ . ": function \"$fName\" is an abstract method, please implement it in \"$class\"");
126			#exit;
127			}
128
129			sub _typeCheck {
130			my $type = shift;
131			print "type: $type";
132			eval("use Data::Storage::$type;");
133			}
134
135			sub _getMetaInfo {
136			my $packagename = shift;
137			#return $self->$metainfo;
138
139			my $ns = '$' . $packagename . "::metainfo";
140			$logger->debug( __PACKAGE__ . "->" . "_getMetaInfo()" . " " . "[$ns]" );
141			return eval($ns);
142			}
143
144
145			# ====================================================
146			# PUBLIC METHODS
147			# ====================================================
148
149			# TODO: abstract "abstract methods" to list/hash to be used in AUTOLOAD
150			# e.g.: my @ABSTRACT_METHODS = (qw( connect sendCommand getChildNodes ));
151
152			sub connect {
153
154			my $self = shift;
155			$self->_abstract_function('connect');
156			return;
157
158			$logger->debug( "\"connect\" has to be implemented by handler!" );
159			return;
160
161			# my $self = shift;
162			# my $connectionString = shift;
163			# # todo: patch connectionString to $args
164			# _typeCheck($self->{args}{type});
165
166			}
167
168			sub sendCommand {
169			my $self = shift;
170			$self->_abstract_function('sendCommand');
171			}
172
173			sub getChildNodes {
174			my $self = shift;
175			$self->_abstract_function('getChildNodes');
176			}
177
178			sub configureCOREHANDLE {
179			my $self = shift;
180			$self->_abstract_function('configureCOREHANDLE');
181			}
182
183			1;
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