/**
* Attempt to create an instance of thea provider for the given service
*
* @param cls class
* @return created instance
*/
static <T, X extends T> T createProviderForClass(
final PluggableService<T> service, final Class<X> cls)
throws PluginException, ProviderCreationException {
debug("Try loading provider " + cls.getName());
final Plugin annotation = getPluginMetadata(cls);
final String pluginname = annotation.name();
if (!service.isValidProviderClass(cls)) {
throw new PluginException(
"Class "
+ cls.getName()
+ " was not a valid plugin class for service: "
+ service.getName()
+ ". Expected class "
+ cls.getName()
+ ", with a public constructor with no parameter");
}
debug("Succeeded loading plugin " + cls.getName() + " for service: " + service.getName());
return service.createProviderInstance(cls, pluginname);
}
/** Load provider instance for the service */
@SuppressWarnings("unchecked")
public synchronized <T> T load(final PluggableService<T> service, final String providerName)
throws ProviderLoaderException {
final ProviderIdent ident = new ProviderIdent(service.getName(), providerName);
debug("loadInstance for " + ident + ": " + pluginJar);
if (null == pluginProviderDefs.get(ident)) {
final String[] strings = getClassnames();
for (final String classname : strings) {
final Class<?> cls;
try {
cls = loadClass(classname);
if (matchesProviderDeclaration(ident, cls)) {
pluginProviderDefs.put(ident, cls);
}
} catch (PluginException e) {
log.error(
"Failed to load class from "
+ pluginJar
+ ": classname: "
+ classname
+ ": "
+ e.getMessage());
}
}
}
final Class<T> cls = pluginProviderDefs.get(ident);
if (null != cls) {
try {
return createProviderForClass(service, cls);
} catch (PluginException e) {
throw new ProviderLoaderException(e, service.getName(), providerName);
}
}
return null;
}