sirius.kernel.extensions

Class Extensions

java.lang.Object

sirius.kernel.extensions.Extensions

@ParametersAreNonnullByDefault
public class Extensions
extends Object

Extension system based on the system configuration, providing simple access to extension lists.

Using the typesafe config library, several component.conf (along with application.conf etc.) will be loaded to form the system config (see: Sirius.setupConfiguration()). These files will be merged together, so that extensions like the following wil be put into one extension list reachable as "examples":

 
     File A:

      examples {
          A = {
              key = "string"
              otherKey = true
          }
      }

     File B:

      examples {
          B = {
              key = "string"
              otherKey = true
          }
      }
 
 

This permits frameworks to provide extension hooks which can be extended by sub modules, without having the framework to "know" those modules. Using a loose coupled approach like this simplifies the task of building modular and extensible systems.

The extensions defined above can be obtained calling Extensions.getExtension("examples"). Each of those extensions can be read out calling ext.getValue("key").asString() or ext.getValue("otherKey").asBoolean()

Another way of loading extensions is to place an ExtensionList annotation on a field like:

 
     @ExtensionList("examples")
     private List<Extension> examples;
 
 

This will be detected by the ExtensionListAnnotationProcessor as the Injector starts up and filled with the appropriate list.

See Also:

Extension, Value, Sirius.setupConfiguration()

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT Name of the default entry for an extension
protected static Log	LOG The logger used by the extensions framework

Method Summary

Modifier and Type	Method and Description
static Extension	getExtension(String type, String id) Returns the Extension for the given id of the given type
static Collection<Extension>	getExtensions(String type) Returns all extensions available for the given type The order of the extensions can be defined, setting a property named priority.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT

public static final String DEFAULT

Name of the default entry for an extension

See Also:

Constant Field Values

LOG

protected static final Log LOG

The logger used by the extensions framework

Method Detail

getExtension

@Nullable
public static Extension getExtension(String type,
                                               String id)

Returns the Extension for the given id of the given type

Parameters:

type - the type of the extension to be returned

id - the unique id of the extension to be returned

Returns:

the specified extension or null, if no such extension exists

getExtensions

@Nonnull
public static Collection<Extension> getExtensions(String type)

Returns all extensions available for the given type

The order of the extensions can be defined, setting a property named priority. If no value is present PriorityCollector.DEFAULT_PRIORITY is assumed.

Parameters:

type - the type of the extensions to be returned.

Returns:

a non-null collection of extensions found for the given type