private List<ApplicationClass> inspectApplications(File artifactFile)
throws IOException, InvalidArtifactException {
List<ApplicationClass> apps = Lists.newArrayList();
Location artifactLocation = Locations.toLocation(artifactFile);
Manifest manifest = BundleJarUtil.getManifest(artifactLocation);
if (manifest == null) {
return apps;
}
Attributes manifestAttributes = manifest.getMainAttributes();
if (manifestAttributes == null) {
return apps;
}
// right now we force users to include the application main class as an attribute in their
// manifest,
// which forces them to have a single application class.
// in the future, we may want to let users do this or maybe specify a list of classes or
// a package that will be searched for applications, to allow multiple applications in a single
// artifact.
String mainClassName = manifestAttributes.getValue(ManifestFields.MAIN_CLASS);
if (mainClassName != null) {
try (CloseableClassLoader artifactClassLoader =
artifactClassLoaderFactory.createClassLoader(Locations.toLocation(artifactFile))) {
Object appMain = artifactClassLoader.loadClass(mainClassName).newInstance();
if (!(appMain instanceof Application)) {
throw new InvalidArtifactException(
String.format(
"Application main class is of invalid type: %s", appMain.getClass().getName()));
}
Application app = (Application) appMain;
TypeToken typeToken = TypeToken.of(app.getClass());
TypeToken<?> resultToken = typeToken.resolveType(Application.class.getTypeParameters()[0]);
Type configType;
// if the user parameterized their template, like 'xyz extends ApplicationTemplate<T>',
// we can deserialize the config into that object. Otherwise it'll just be a Config
if (resultToken.getType() instanceof Class) {
configType = resultToken.getType();
} else {
configType = Config.class;
}
apps.add(new ApplicationClass(mainClassName, "", schemaGenerator.generate(configType)));
} catch (ClassNotFoundException e) {
throw new InvalidArtifactException(
String.format("Could not find Application main class %s.", mainClassName));
} catch (UnsupportedTypeException e) {
throw new InvalidArtifactException(
String.format("Config for Application %s has an unsupported schema.", mainClassName));
} catch (InstantiationException | IllegalAccessException e) {
throw new InvalidArtifactException(
String.format("Could not instantiate Application class %s.", mainClassName), e);
}
}
return apps;
}
// passed app to be used to resolve default name and description
public DefaultAppConfigurer(Application app) {
this.name = app.getClass().getSimpleName();
this.description = "";
}