en:user_advanced:classifiers
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— | en:user_advanced:classifiers [2023/03/13 01:46] (current) – created - external edit 127.0.0.1 | ||
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+ | ====== Browsing Classifiers ======= | ||
+ | |||
+ | The information used to support browsing is stored in the collection information | ||
+ | database, and is placed there by classifiers that are called during the final phase of | ||
+ | '' | ||
+ | |||
+ | Classifiers, | ||
+ | For each one there is a line starting with the keyword // | ||
+ | of the classifier and any options it takes. The basic collection configuration file discussed | ||
+ | in Section [[# | ||
+ | AZList—metadata Title//, which makes an alphabetic list of titles by taking all those with | ||
+ | a //Title// metadata field, sorting them and splitting them into alphabetic ranges. | ||
+ | An example is shown in Figure <imgref figure_azlist_classifier> | ||
+ | |||
+ | |||
+ | The lines used to specify classifiers in collection configuration | ||
+ | files contain a // | ||
+ | documents are classified and sorted. Any document in the collection that does not | ||
+ | have this metadata defined will be omitted from the classifier | ||
+ | (but it is still indexed, and consequently searchable). | ||
+ | If no // | ||
+ | in the order in which they are encountered during the building process. This is useful | ||
+ | if you want a list of all documents in your collection. | ||
+ | |||
+ | There is a | ||
+ | // | ||
+ | and the options it provides. These options can also be viewed on the classifiers' | ||
+ | pages, which can be reached from the [[en: | ||
+ | |||
+ | |||
+ | Collection-specific classifiers can be written, | ||
+ | and are stored in the collection' | ||
+ | The Development Library has a collection-specific classifier called | ||
+ | // | ||
+ | |||
+ | |||
+ | ===== How classifiers work ===== | ||
+ | |||
+ | Classifiers are Perl objects, derived from // | ||
+ | |||
+ | - The //new// method creates the classifier object. | ||
+ | - The //init// method initialises the object with parameters such as metadata type, button name and sort criterion. | ||
+ | - The // | ||
+ | - The // | ||
+ | |||
+ | The // | ||
+ | |||
+ | The build process initialises the classifiers as soon as the //builder// object is created. Classifications are created during the build phase, when the information database is created, by // | ||
+ | |||
+ | ===== Dynamic classifiers ===== | ||
+ | |||
+ | Currently only available for Greenstone 2. If a collection uses sqlite or MSSQL as the collection database, then it can provide dynamic classifiers. These are generated at runtime, so don't need to be rebuilt everytime documents are added. **kjdon-TODO** finish this section. |
en/user_advanced/classifiers.txt · Last modified: 2023/03/13 01:46 by 127.0.0.1