Package org.apache.wiki.util

Class PropertyReader

java.lang.Object
org.apache.wiki.util.PropertyReader
public final class PropertyReader extends Object
Property Reader for the WikiEngine. Reads the properties for the WikiEngine and implements the feature of cascading properties and variable substitution, which come in handy in a multi wiki installation environment: It reduces the need for (shell) scripting in order to generate different jspwiki.properties to a minimum.
Since:
2.5.x

  • Field Details

  • Method Details

    • loadWebAppProps

      public static Properties loadWebAppProps(javax.servlet.ServletContext context)
      Loads the webapp properties based on servlet context information, or (if absent) based on the Java System Property "jspwiki.custom.config". Returns a Properties object containing the settings, or null if unable to load it. (The default file is ini/jspwiki.properties, and can be customized by setting "jspwiki.custom.config" in the server or webapp configuration.)

      Properties sources

      The following properties sources are taken into account:
      1. JSPWiki default properties
      2. System environment
      3. JSPWiki custom property files
      4. JSPWiki cascading properties
      5. System properties
      With later sources taking precedence over the previous ones. To avoid leaking system information, only System environment and properties beginning with jspwiki (case unsensitive) are taken into account. Also, to ease docker integration, System env properties containing "_" are turned into ".". Thus, ENV jspwiki_fileSystemProvider_pageDir is loaded as jspwiki.fileSystemProvider.pageDir.

      Cascading Properties

      You can define additional property files and merge them into the default properties file in a similar process to how you define cascading style sheets; hence we call this cascading property files. This way you can overwrite the default values and only specify the properties you need to change in a multiple wiki environment.

      You define a cascade in the context mapping of your servlet container. 

        jspwiki.custom.cascade.1
  jspwiki.custom.cascade.2
  jspwiki.custom.cascade.3
      and so on. You have to number your cascade in a descending way starting with "1". This means you cannot leave out numbers in your cascade. This method is based on an idea by Olaf Kaus, see [JSPWiki:MultipleWikis].
      Parameters:
      context - A Servlet Context which is used to find the properties
      Returns:
      A filled Properties object with all the cascaded properties in place

    • getDefaultProperties

      public static Properties getDefaultProperties()
      Returns the property set as a Properties object.
      Returns:
      A property set.

    • getCombinedProperties

      public static Properties getCombinedProperties(String fileName)
      Returns a property set consisting of the default Property Set overlaid with a custom property set
      Parameters:
      fileName - Reference to the custom override file
      Returns:
      A property set consisting of the default property set and custom property set, with the latter's properties replacing the former for any common values

    • propertyExpansion

      public static void propertyExpansion(Properties properties)

      Try to resolve properties whose value is something like ${SOME_VALUE} from a system property first and, if not found, from a system environment variable. If not found on neither, the property value will remain as ${SOME_VALUE}, and no more expansions will be processed.

      Several expansions per property is OK, but no we're not supporting fancy things like recursion. Reference to other properties is achieved through expandVars(Properties). More than one property expansion per entry is allowed.

      Parameters:
      properties - properties to expand;

    • expandVars

      public static void expandVars(Properties properties)

      You define a property variable by using the prefix var.x as a property. In property values you can then use the "$x" identifier to use this variable.

      For example, you could declare a base directory for all your files like this and use it in all your other property definitions with a $basedir. Note that it does not matter if you define the variable before its usage. 

        var.basedir = /p/mywiki; # var.basedir = ${TOMCAT_HOME} would also be fine
  jspwiki.fileSystemProvider.pageDir =         $basedir/www/
  jspwiki.basicAttachmentProvider.storageDir = $basedir/www/
  jspwiki.workDir =                            $basedir/wrk/

      Parameters:
      properties - - properties to expand;

    • locateClassPathResource

      public static InputStream locateClassPathResource(javax.servlet.ServletContext context, String resourceName)
      Locate a resource stored in the class path. Try first with "WEB-INF/classes" from the web app and fallback to "resourceName".
      Parameters:
      context - the servlet context
      resourceName - the name of the resource
      Returns:
      the input stream of the resource or null if the resource was not found