---
name: "RDF::Trine::Store::LanguagePreference"
section: "3pm"
platform: "linux"
package: "librdf-trine-perl"
version: "1.019-4"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/RDF::Trine::Store::LanguagePreference"
---

# RDF::Trine::Store::LanguagePreference(3pm)

RDF Store proxy for filtering language tagged literals

## NAME

RDF::Trine::Store::LanguagePreference - RDF Store proxy for filtering language tagged literals

## VERSION

This document describes RDF::Trine::Store::LanguagePreference version 1.019

## SYNOPSIS

```
 use RDF::Trine::Store::LanguagePreference;
```

## DESCRIPTION

RDF::Trine::Store::LanguagePreference provides a RDF::Trine::Store API to filter the statements made available from some underlying store object based on a users' language preferences (e.g. coming from an Accept-Language HTTP header value).

## METHODS

Beyond the methods documented below, this class inherits methods from the RDF::Trine::Store class.

- "new ( $store, { $lang1 =\> $q1, $lang2 =\> $q2, ... } )"

  Returns a new storage object that will act as a proxy for the `$store` object, filtering language literals based on the expressed language preferences.

- "new\_with\_config ( $hashref )"

  Returns a new storage object configured with a hashref with certain keys as arguments.

  The `"storetype"` key must be `"LanguagePreference"` for this backend.

  The following key must also be used:

  - "store"

    A configuration hash for the underlying store object.

  - "preferred\_languages"

    A hash reference mapping language tags to quality values in the range \[0, 1\]. The referent may be changed between operations to change the set of preferred languages used in statement matching.

- "new\_with\_config ( \\%config )"

  Returns a new RDF::Trine::Store object based on the supplied configuration hashref.

- "language\_preferences"

  Returns a hash of the language preference quality values.

- language\_preference( $lang )

  Return the quality value preference for the given language.

- "update\_language\_preference( $lang =\> $qvalue )"

  Update the quality value preference for the given language.

- "get\_statements ( $subject, $predicate, $object \[, $context\] )"

  Returns a stream object of all statements matching the specified subject, predicate and objects. Any of the arguments may be undef to match any value.

- "count\_statements ( $subject, $predicate, $object, $context )"

  Returns a count of all the statements matching the specified subject, predicate, object, and context. Any of the arguments may be undef to match any value.

- "qvalueForLanguage ( $language, \\%cache )"

  Returns the q-value for `$language` based on the current language preference. `%cache` is used across multiple calls to this method for performance reasons.

- "siteQValueForLanguage ( $language )"

  Returns an implementation-specific q-value preference for the given `$language`. This method may be overridden by subclasses to control the default preferred language.

- availableLanguagesForStatement( $statement )

  Returns a list of language tags that are available in the underlying store for the given statement object. For example, if `$statement` represented the triple:

  ```
   dbpedia:Los_Angeles rdf:label "Los Angeles"@en
  ```

  and the underlying store contains the triples:

  ```
   dbpedia:Los_Angeles rdf:label "Los Angeles"@en
   dbpedia:Los_Angeles rdf:label "ロサンゼルス"@ja
   dbpedia:Los_Angeles rdf:label "Лос-Анджелес"@ru
  ```

  then the return value would be `"('en', 'ja', 'ru')"`.

- "languagePreferenceAllowsStatement ( $statement, \\%cache )"

  Returns true if the `$statement` is allowed by the current language preference. `%cache` is used across multiple calls to this method for performance reasons.

- "supports ( \[ $feature \] )"

  If `$feature` is specified, returns true if the feature is supported by the store, false otherwise. If `$feature` is not specified, returns a list of supported features.

## BUGS

Please report any bugs or feature requests to through the GitHub web interface at \<https://github.com/kasei/perlrdf/issues\>.

## AUTHOR

Gregory Todd Williams  `"<gwilliams@cpan.org>"`

## COPYRIGHT

Copyright (c) 2006-2012 Gregory Todd Williams. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.