I have a remark: from my experience, in big projects, people tend to create lots of configuration files for each modules and at the end it appears to be really hard to maintain something coherent and easy to use. You spend more time looking in files to find the parameter you need to change and if documentation is not perfect, this can become totally impossible for a non-expert. imagine if you have 50 modules, you may have 50 different places for configuration? So will it be possible to aggregate configurations to centralize data and optimize configuration mechanisms? regards Pascal On Mon, Aug 25, 2008 at 2:17 PM, Marius Dumitru Florea < [email protected]> wrote:
Hi Vincent,
I like it. Just make sure this configuration components will be available in velocity code as well. As you know, I had to write a plug-in for the WYSIWYG mainly because currently there's no way of getting a XWiki configuration parameter without having programming rights. Also, I think we should allow a configuration source to contain parameters for different modules. But I guess this is easy to implement using the namespaces you mentioned.
So I'm definitely +1.
Hi,
Here's a proposal for implementing configuration in the new architecture, using components. Note: I think this is compatible with Sergiu's proposal here: http://tinyurl.com/6md5jd
General requirements =================
* Each module/component can define its own configuration * Accessing configuration parameters from Java should be strongly typed (ie. getLinkLabelFormat() for getting the link label and not getParameter("linklabelformat")) * It should be possible to load Configuration data from different sources (properties file, xml files, database, xwiki documents, etc) * Configuration sources should have an order * Any module/component should be able to get the configuration for other module/component but in read only mode * It should be possible to dynamically add a new configuration source at runtime * Configuration data should be loaded and cached
Proposed Implementation ====================
* Each module/component defines its configuration in a component which is a java beans. For example let's take the rendering module. We would have a RenderingConfiguration component as in:
public interface RenderingConfiguration { String getLinkLabelFormat(); }
public class DefaultRenderingConfiguration implements Initializable, Reloadable, RenderingConfiguration (in practice will extend AbstractConfiguration class probably) { private String linkLabelFormat;
// Injected private ConfigurationManager manager;
public void initialize() { // Define the Configuration sources here. Default configuration sources would be defined in AbstractConfiguration probably) List configurationSources = ....
// Configuration namespace (all properties should start with the namespace value) String namespace = "rendering";
reload(); }
// Should be located in AbstractConfiguration public void addConfigurationSource(ConfigurationSource source);
public void reload() { // Populate java bean manager.populate(this, configurationSources, namespace); }
public void setLinkLabelFormat(String linkLabelFormat) {...} public String getLinkLabelFormat() {...} }
* The DefaultRenderingConfiguration class is registered as a component in components.xml and with a singleton lifecycle. This means the data it contains are cached for the whole application lifetime. They can be reloaded using reload(). * The ConfigurationManager implementation will use Jakarta BeanUtils to automatically populate a javabeans. It'll also use Jakarta Commons Configuration for implementations of ConfigurationSource. * ConfigurationSource interface should have a method like: Object getParameter(String name). More details to be defined later. * Code wanting to get Rendering Configuration would simply define a component dependency on DefaultRenderingConfiguration and they'll have it injected for them. * There'll be a XWikiDocumentConfigurationSource that gets parameter values from one or several xwiki documents. We'll need to define how we get them but we could provide some standard XWikiConfigurationClass for a single configuration element for example. * The idea of the namespace is to use the package name and remove the "org.xwiki" or "com.xpn.xwiki" prefix. For example "org.xwiki.rendering.*" leads to "rendering.*".
WDYT?
If we agree I can whip up a first implementation of this relatively quickly I think.
Thanks -Vincent
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