Index: xdocs/changes.xml =================================================================== --- xdocs/changes.xml (revision 713250) +++ xdocs/changes.xml (working copy) @@ -85,6 +85,10 @@ + + Added MultiFileHierarchicalConfiguration, DynamicCombinedConfiguration + and PatternSubtreeConfigurationWrapper. + PropertiesConfiguration now per default uses the encoding "ISO-8859-1" for loading properties files. Index: xdocs/userguide/howto_multitenant.xml =================================================================== --- xdocs/userguide/howto_multitenant.xml (revision 0) +++ xdocs/userguide/howto_multitenant.xml (revision 0) @@ -0,0 +1,148 @@ + + + + + + + Mutli-tenant Configurations + Ralph Goers + + + +
+

+ In a multi-tenant environment a single instance of the application + while run on behalf of many clients. Typically, this will require + that each client have its own unique configuration. The simplest + approach to enable an application to be multi-tenant is for it + to not really be aware of it at all. This requires that the + configuration framework take on some of the responsility for + making the application work correctly. +

+

+ One approach to enable this support in a web application might be + to use a Servlet Filter and then use the Log4j or SLF4J MDC to + save the attributes needed to identify the client. These attributes + can then be used to identify the specific client configuration to + be used. The classes described below use this technique to allow + configurations to transparently provide the configuration appropriate + for the clients. +

+ + +

+ The constructor for this class accepts a pattern. The pattern can + contain keys that will be resolved using the ConfigurationInterpolator + on each call to a method in the class. The configuration file will then + be located using the resolved pattern and a new XMLConfiguration + will be created and cached for subsequent requests. The ExpressionEngine, + ReloadingStrategy and listeners will be propogated to each of the + created configurations. +

+ + +

+ The CombinedConfiguration class allows multiple configuration files to be + merged together. However, it will not merge a MultiFileHierarchicalConfiguration + properly since the underlying configuration file will be different depending + on the resolution of the location pattern. DynamicCombinedConfiguration + solves this by creating a new CombinedConfiguration for each pattern. +

+ + +

+ This sample configuration illustrates how to use DynamicCombinedConfiguration + in combination with MultiFileHierarchicalConfiguration to create a multi-tenant + configuration. +

+ + + +
+ + + + + + +
+ + + + + +]]> + + +

+ Applications are often composed of many components each of which need their + own configuration. This can be accomodated by having a configuration file + per component, but this can make things hard to manage when there are many + clients and many components. A second approach is to combine them into + a single configuration file. However, this either means the subcomponent + has to be aware of the surrounding configuration and navigate past it or the + application must be provided just the portion of the configuration it + can process. PatternSubtreeConfigurationWrapper can be used for this purpose. +

+

+ Normal practice when using dependency injection frameworks is to have the + attributes needed to make components work correctly injected into them. + When working with Commons Configuration this works very well. Components + simply need to have a HierarchicalConfiguration attribute along with + a corresponding setter and getter. The injection framework can then be + used to provide the component with the correct configuration using + PatternSubtreeConfigurationWrapper as shown in the next example. +

+

+ + + configuration.xml + + + + + + + + + + + + + + +]]> +

+ +
+ + + + Index: xdocs/userguide/user_guide.xml =================================================================== --- xdocs/userguide/user_guide.xml (revision 713250) +++ xdocs/userguide/user_guide.xml (working copy) @@ -132,6 +132,13 @@
  • An example
  • Extending the configuration definition file format
    • +
  • Multi-tenant Configurations
    • +
  • Configuration Events