source: trunk/gsdl/perllib/classify/BasClas.pm@ 1885

Last change on this file since 1885 was 1885, checked in by paynter, 23 years ago

Added a classinfo.pl script, analogous to pluginfo.pl, that provides
information about a given classifier. Tweaked BasClas to format output
corrwectly, but many of the other classifiers still need a bit of work.

  • Property svn:keywords set to Author Date Id Revision
File size: 3.5 KB
Line 
1###########################################################################
2#
3# BasClas.pm -- base class for all classifiers
4#
5# A component of the Greenstone digital library software
6# from the New Zealand Digital Library Project at the
7# University of Waikato, New Zealand.
8#
9# Copyright (C) 2000 New Zealand Digital Library Project
10#
11# This program is free software; you can redistribute it and/or modify
12# it under the terms of the GNU General Public License as published by
13# the Free Software Foundation; either version 2 of the License, or
14# (at your option) any later version.
15#
16# This program is distributed in the hope that it will be useful,
17# but WITHOUT ANY WARRANTY; without even the implied warranty of
18# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19# GNU General Public License for more details.
20#
21# You should have received a copy of the GNU General Public License
22# along with this program; if not, write to the Free Software
23# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24#
25###########################################################################
26
27package BasClas;
28
29# How a classifier works.
30#
31# For each classifier requested in the collect.cfg file, buildcol.pl creates
32# a new classifier object (a subclass of BasClas). Later, it passes each
33# document object to each classifier in turn for classification.
34#
35# Four primary functions are used:
36#
37# 1. "new" is called before the documents are processed to set up the
38# classifier.
39#
40# 2. "init" is called after buildcol.pl has created the indexes etc but
41# before the documents are classified in order that the classifier might
42# set any variables it requires, etc.
43#
44# 3. "classify" is called once for each document object. The classifier
45# "classifies" each document and updates its local data accordingly.
46#
47# 4. "get_classify_info" is called after every document has been
48# classified. It collates the information about the documents and
49# stores a reference to the classifier so that Greenstone can later
50# display it.
51
52use parsargv;
53
54sub print_general_usage {
55 my ($plugin_name) = @_;
56 print STDERR "
57 -verbosity N Controls the quantity of output.
58 Defaults to verbosity of buildcol.pl, which is usually 2.
59
60 (Most general classifier options are set internally by buildcol.)
61
62";
63}
64
65# print_usage should be overridden for any sub-classes
66sub print_usage {
67 print STDERR "
68This classifier has no classifier-specific options
69
70";
71}
72
73sub new {
74 my $class = shift (@_);
75 my $name = shift (@_);
76
77 my $self = {};
78
79 $self->{'outhandle'} = STDERR;
80
81 # general options available to all classifiers
82 if (!parsargv::parse(\@_,
83 q^builddir/.*/^, \$self->{'builddir'},
84 q^outhandle/.*/STDERR^, \$self->{'outhandle'},
85 q^verbosity/\d/2^, \$self->{'verbosity'},
86 "allow_extra_options")) {
87
88 print STDERR "\nThe $name classifier uses an incorrect general option\n";
89 print STDERR "(general options are those available to all classifiers).\n";
90 print STDERR "Check your collect.cfg configuration file.\n";
91 &print_general_usage($plugin_name);
92 die "\n";
93 }
94
95
96
97 return bless $self, $class;
98}
99
100sub init {
101 my $self = shift (@_);
102}
103
104sub classify {
105 my $self = shift (@_);
106 my ($doc_obj) = @_;
107
108 my $outhandle = $self->{'outhandle'};
109 print $outhandle "BasClas::classify function must be implemented in sub-class\n";
110}
111
112sub get_classify_info {
113 my $self = shift (@_);
114
115 my $outhandle = $self->{'outhandle'};
116 print $outhandle "BasClas::classify function must be implemented in sub-class\n";
117}
118
1191;
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