Mulitilingual Document handling
Introduction
Mulitilingual Document handling deals with documents of different languages. This affects virtually every part of Lenya, namely many aspects of work flow such as creation, publication, deactivation, deletion. It also affects access control, meta data, etc.
The multilingual capabilities are not a mandatory feature of
Lenya. You can easily create monolingual publication by simply
replacing a few properties in
publication.xconf.
The multilingual capabilities are deeply ingrained in the core of Lenya and as such a conceptual overview has to delve into many areas of Lenya. The main parts of the multilingual capabilities are as follows:
- Site tree
- The site
tree contains information about documents. It has been
expanded to also contain information about different language
versions of the same document. Different language versions of
the same document share the same
document-id. - Default language
- A publication has a default language. This is the language
in which the document is created. However it is not
necessarily the case that there is always a document version
in the default language as the user is allowed to remove any
language version even the one for the default language.
If you specify an URL without a language suffix you are redirected to the default language document. - publication.xconf
- This is where the available languages and the default language are specified.
- page-envelope
- The page envelope exports document specific information such as document-id via an input module. Naturally language specific information for the current document is also available via the page envelope.
- Redirection
- If you request a document
foo.htmlin a multilingual publication you will internally be redirected tofoo_en.htmlif "en" is the default language. - Special cases
- Some special care has to be taken when removing language versions. The current implementation does not allow the user to remove all language versions of a document. There always has to be at least one language version.
Implementation
Site tree
The site tree contains nodes for each document. Each node
can contain multiple label nodes for each
language version of the document.
<node id="doctypes"> <label xml:lang="de">Dokumenttypen</label> <label xml:lang="en">Document types</label> <node id="1column"> <label xml:lang="de">1 Spalte</label> </node> </node>
The classe SiteTree and
SiteTreeNode provide interfaces to the nodes and
the corresponding label nodes.
publication.xconf
The languages node in
publication.xconf defines the languages that are
available for this publication and also defines the default language.
<languages> <language default="true">de</language> <language>en</language> </languages>
This information is available via the
Publication class
(getDefaultLanguage() and
getLanguages() methods).
page-envelope
The page-envelope
input module exports language related information,
namely default-language,
document-label, document-language,
document-languages and
document-languages-csv.
Redirection
The DefaultDocumentBuilder which implements the
DocumentBuilder interface, takes care of
redirecting language agnostic URLs (such as
foo.html) to language aware links
(foo_en.html), i.e. language agnostic links are
redirected to the language aware link with the default language.
Addition and removal
More language versions are added with the "Create new
language version" screen. Existing language versions can be
removed with the "Remove Language" screen. These screens are
generated by create-language.xsp,
create-language.xsl, removelabel.xsp
and removelabel.xsl.
The creation of a new language version is done via the
create-language target which uses the
InsertLabelTask ant task to insert a label in the
site tree.
The removal of a language version is done via the
remove-language target, which uses the
RemoveLabelTask ant task (which removes the label
from the site tree).
Involved classes, XSPs and XSLTs
The following classes, XSPs and XSLTs are involved in multilingual document handling:
- org.apache.lenya.cms.publication.SiteTree and org.apache.lenya.cms.publication.SiteTreeNode
- These interfaces provide acces to the label nodes.
- org.apache.lenya.cms.publication.Publication
- Provides access to the default language and to all available languages.
- org.apache.lenya.cms.publication.PageEnvelope
- Exports language related information such as
default-language,document-language, etc. - org.apache.lenya.cms.publication.DefaultDocumentBuilder
- Builds a document with the given language. The default
implementation also takes care of redirecting
foo.htmltofoo_en.html. - $publication-id/lenya/content/authoring/create-language.xsp, $publication-id/lenya/xslt/authoring/create-language.xsl
- Generate the "Create new language version" screen.
- src/webapp/lenya/content/authoring/removelabel.xsp, src/webapp/lenya/xslt/authoring/removelabel.xsl
- Generate the "Remove Language" screen.
- org.apache.lenya.cms.ant.InsertLabelTask
- Ant task to add a label to the site tree.
- org.apache.lenya.cms.ant.RemoveLabelTask
- Ant task to remove a label from the site tree.
- $publication-id/config/tasks/targets.xml
- Defines the
create-languageand theremove-languagetarget which handle the addition and removal of language versions of a document.