Apache Sling Resource Presence
This module is part of the Apache Sling project.
This module creates proxy OSGi services that are registered only if specific resources are present.
Like for example:
@Reference(target="(path=/content/foo/bar)")
private ResourcePresence barIsPresent;
The barIsPresent
service is registered only if the /content/foo/bar
resource is present, allowing OSGi
components to be dependent on the presence of specific Resources.
This is mostly meant for testing, to wait for test content before running specific tests.
Getting Started
-
Configure a service user mapping for
org.apache.sling.resource.presence
to allow reading resources, using e.g. service usersling-readall
. -
Configure a presenter to observe a resource by path, e.g.
path=/apps
Whenever resource
/apps
is available the presenter will register an OSGi service for it and unregister it whenever/apps
gets removed. -
You can depend on that service now, e.g. using a
@Reference
annotation with atarget
on your component:@Reference( target = "(path=/apps)" ) private ResourcePresence apps;
Using Resource Presence with Pax Exam
When running tests with resources involved, you can use a resource presence to delay test execution until required resources are available.
@Inject
@Filter(value = "(path=/apps)")
private ResourcePresence apps;
@Configuration
public Option[] configuration() {
return new Option[]{
[...],
factoryConfiguration("org.apache.sling.resource.presence.internal.ResourcePresenter")
.put("path", "/apps")
.asOption()
};
}
@Test
public void testApps() {
assertThat(apps.getPath(), is("/apps"));
}