Language Definition
This section describes what a language definition and addon are. It is required for component development. However, you could skip it if you won't develop components. For more information about component development, please refer to ZK Component Development Essentials.
If you would like to change the default configuration of a ZK application, please refer to ZK Developer's Reference: Packing Code.
Language Definition
A language definition defines a component set (aka., a language). For example, ZUL and XHTML are two component sets.
To define a language definition, you have to prepare a file called /metainfo/zk/lang.xml and make it available to the classpath (such as in a JAR file, or in WEB-INF/classes of a Web application). In addition, you could specify them in /metainfo/zk/config.xml in the classpath. (parsed by org.zkoss.zk.ui.metainfo.DefinitionLoaders)
Language Addon
A language addon serves to extend a language definition within the ZK framework. You can include a language addon using any of the following methods:
- Path Convention Loading
- In a web application (WAR): Ensure that the file is named lang-addon.xml. Put the file at
/WEB-INF/classes/metainfo/zk/lang-addon.xml. This location makes the file accessible to the classpath. - In a jar file: Put the file at
mymodule.jar/metainfo/zk/lang-addon.xml.
- zk.xml
Specify the file path using the <language-config> element in zk.xml. This method allows you to use any file name for the configuration file. Learn more about this configuration at <language-config> in zk.xml.
- config.xml
For JAR files, specify the file path in the configuration file located at /metainfo/zk/config.xml. This approach is useful when the configuration file needs to be included in the classpath. Further details can be found at /metainfo/zk/config.xml.
These methods provide flexible options for integrating language addons, ensuring they are properly recognized and utilized by the ZK framework.
When ZK starts, it will parse all language definitions and then all language add-ons based on their dependency. A language addon is a variant of a language definition. They are almost the same, except for the naming and it must specify the <addon-name>.
DOCTYPE restriction
Since 10.0.0
Starting from ZK 10, the xml parser used by ZK declares disallow-doctype-decl to true.
This prevents the use of DOCTYPE declaration in xml files, such as zk.xml, lang-addon.xml, config. xml, etc.
This is a security measure to prevent XXE attacks using <!DOCTYPE ...> as vector.