package org.wicketstuff.osgi.inject;
import org.apache.wicket.Application;
import org.apache.wicket.Component;
import org.apache.wicket.application.IComponentInstantiationListener;
import org.apache.wicket.injection.Injector;
import org.wicketstuff.osgi.inject.impl.OsgiFieldValueFactory;
/**
* A hook for injecting OSGi services into Wicket components. This class performs field injection
* for all component fields annotated by {@code @javax.inject.Inject} by looking up a service of the
* required type from the OSGi service registry.
* <p>
* To enable this mechanism, register the injection in your {@link Application#init()} method like
* this:
*
* <pre>
* getComponentInstantiationListeners().add(new OsgiComponentInjector());
* </pre>
*
* By default, injected services are wrapped in a proxy to take care of class loading issues when
* deserializing a component from the page store. On serialization, the proxy replaces the wrapped
* service (which may not be serializable itself) by a serializable reference (its interface name,
* essentially). On deserialization, the proxy retrieves the matching service from the OSGi service
* registry.
* <p>
* TODO Injection is not deterministic when there is more than one service of the required type.
* This class should be extended to disambiguate candidate services either by a {@code @Named}
* qualifier or by a dedicated qualifier taking service properties as parameters.
*
* @author Harald Wellmann
*
*/
public class OsgiComponentInjector extends Injector implements IComponentInstantiationListener
{
private OsgiFieldValueFactory fieldFactory;
public OsgiComponentInjector()
{
this(true);
}
public OsgiComponentInjector(boolean wrapInProxies)
{
fieldFactory = new OsgiFieldValueFactory(wrapInProxies);
}
@Override
public void inject(Object object)
{
inject(object, fieldFactory);
}
public void onInstantiation(Component component)
{
inject(component);
}
}