wicket.resource.loader
Class AbstractStringResourceLoader

java.lang.Object
  wicket.resource.loader.AbstractStringResourceLoader

All Implemented Interfaces:

IStringResourceLoader

Direct Known Subclasses:

ClassStringResourceLoader, ComponentStringResourceLoader, WicketBundleStringResourceLoader

public abstract class AbstractStringResourceLoader
extends java.lang.Object
implements IStringResourceLoader

This abstract string resource loader provides two helper functions to retrieve the message associated with a key, a locale and a style. The simple one uses the Class provided and its parent classes to find the associated message. The more complex one uses in addition the component provided and its parent containers.

The component based string resource loader attempts to find the resource from a bundle that corresponds to the supplied component object or one of its parent containers. Generally the component will be an instance of Page, but it may also be an instance of any reusable component that is packaged along with its own resource files. If the component is not an instance of Page then it must be a component that has already been added to a page.

The search order for resources is built around the containers that hold the component (if it is not a page). Consider a Page that contains a Panel that contains a Label. If we pass the Label as the component then resource loading will first look for the resource against the page, then against the panel and finally against the label.

The above search order may seem slightly odd at first, but can be explained thus: Team A writes a new component X and packages it as a reusable Wicket component along with all required resources. Team B then creates a new container component Y that holds a instance of an X. However, Team B wishes the text to be different to that which was provided with X so rather than needing to change X, they include override values in the resources for Y. Finally, Team C makes use of component Y in a page they are writing. Initially they are happy with the text for Y so they do not include any override values in the resources for the page. However, after demonstrating to the customer, the customer requests the text for Y to be different. Team C need only provide override values against their page and thus do not need to change Y.

This implementation is fully aware of both locale and style values when trying to obtain the appropriate resources.

In addition to the above search order, each key will be pre-pended with the relative path of the current component related to the component that is being searched. E.g. assume a component hierarchy like page1.form1.input1 and your are requesting a key named 'RequiredValidator'. Wicket will search the property in the following order:

    page1.properties => form1.input1.RequiredValidator
    page1.properties => RequiredValidator
    form1.properties => input1.RequiredValidator
    form1.properties => RequiredValidator
    input1.properties => RequiredValidator
    myApplication.properties => page1.form1.input1.RequiredValidator
    myApplication.properties => RequiredValidator
 

In addition to the above search order, each component that is being searched for a resource also includes the resources from any parent classes that it inherits from. For example, PageA extends CommonBasePage which in turn extends WebPage. When a resource lookup is requested on PageA, the resource bundle for PageA is first checked. If the resource is not found in this bundle then the resource bundle for CommonBasePage is checked. This allows designers of base pages and components to define default sets of string resources and then developers implementing subclasses to either override or extend these in their own resource bundle.

You may enable log debug messages for this class to fully understand the search order.

Author:

Chris Turner, Juergen Donnerstag

Field Summary

protected Application

application Wickets application object

Constructor Summary

AbstractStringResourceLoader(Application application)
Create and initialise the resource loader.

Method Summary

protected Properties	getProperties(java.lang.Class clazz, java.util.Locale locale, java.lang.String style) Get (or load) the properties associated with clazz, locale and style.
protected boolean	isStopResourceSearch(java.lang.Class clazz) Check the supplied class to see if it is one that we shouldn't bother further searches up the class hierarchy for properties.
java.lang.String	loadStringResource(java.lang.Class clazz, java.lang.String key, java.util.Locale locale, java.lang.String style) Get the string resource for the given combination of class, key, locale and style.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

application

protected final Application application

Wickets application object

Constructor Detail

AbstractStringResourceLoader

public AbstractStringResourceLoader(Application application)

Create and initialise the resource loader.

Parameters:

application - Wickets application object

Method Detail

loadStringResource

public java.lang.String loadStringResource(java.lang.Class clazz,
                                           java.lang.String key,
                                           java.util.Locale locale,
                                           java.lang.String style)

Get the string resource for the given combination of class, key, locale and style. The information is obtained from a resource bundle associated with the provided Class (or one of its super classes).

Specified by:

loadStringResource in interface IStringResourceLoader

Parameters:

clazz - The Class to find resources to be loaded

key - The key to obtain the string for

locale - The locale identifying the resource set to select the strings from

style - The (optional) style identifying the resource set to select the strings from (see Session)

Returns:

The string resource value or null if resource not found

getProperties

protected Properties getProperties(java.lang.Class clazz,
                                   java.util.Locale locale,
                                   java.lang.String style)

Get (or load) the properties associated with clazz, locale and style.

Parameters:

clazz - The class to find resources to be loaded

locale - The locale identifying the resource set to select the strings from

style - The (optional) style identifying the resource set to select the strings from (see Session)

Returns:

The string resource value or null if resource not found

isStopResourceSearch

protected boolean isStopResourceSearch(java.lang.Class clazz)

Check the supplied class to see if it is one that we shouldn't bother further searches up the class hierarchy for properties.

Parameters:

clazz - The class to check

Returns:

Whether to stop the search