I'm currently trying to create a GlobalExtension for my Geb-Spock framework. So far here is my extension:
class OnFailureListener extends AbstractRunListener {
private final String id
private final SauceREST sauceREST
public OnFailureListener(String id, String username, String accessKey) {
this.id = id
this.sauceREST = new SauceREST(username, accessKey)
}
def void error(ErrorInfo error) {
println error;
this.sauceREST.updateJobInfo(this.sessionIdProvider.getSessionId(), "failed")
}
}
class ResultExtension extends AbstractGlobalExtension {
protected final String username = System.getenv("SAUCE_USERNAME")
protected final String accesskey = System.getenv("SAUCE_ACCESS_KEY")
protected final String sessionId
#Override
void visitSpec(SpecInfo specInfo) {
specInfo.addListener(new OnFailureListener(sessionId, username, accesskey))
}
}
My issue is that the sesssionId value gets assigned in the GebSpec base class I'm using for other specs, and cannot be assigned directly in the extension class. Beyond using some gnarly reflection approaches, is there a way to access the sessionId value assigned in the base class in the extension? I'd also like to avoid using an AnnotationExtension since I'd like to apply this globally without modifying any spec code (similar to a JUnit TestWatcher pattern).
The easiest way for you would be to write the sessionId into a shared ThreadLocal that can be accessed by your listener and the spec, otherwise you'll have to implement an org.spockframework.runtime.extension.IMethodInterceptor so that you can gain access to the actual test instance to extract the field value.
Related
How can I abstract that a methods has optional parameters?
abstract class CopyWith<T>{
T copyWith({}); // Error : Expected an identifier.
}
If I add an identifier like {test} it works and subclasses can have additional arguments
What I want to achieve?
I have a complex state manager, I make some abstraction , the following code is a minimal code, show my problem
import 'dart:collection';
abstract class CopyWith<T> {
T copyWith(OPTIONAL_NAMED_ARGUMENTS);
}
abstract class Manager<K, V extends CopyWith> {
final _map = HashMap<K, V>();
add(K key,V value){
_map[key] = value;
}
void copyWith(K key,OPTIONAL_NAMED_ARGUMENTS) {
assert(key != null);
if (_map.containsKey(key)) {
_map[key].copyWith(OPTIONAL_NAMED_ARGUMENTS);
}
}
}
class User implements CopyWith {
final int id;
final String name;
User({this.id, this.name});
User copyWith({int id, String name}) {
return User(
id: id ?? this.id,
name: name ?? this.name,
);
}
}
class UserManager extends Manager<int, User> {}
void main() {
final userManager = UserManager();
userManager.add(1,User(1,'test'));
userManager.copyWith(1,{test:'test2'})
}
As some one who has faced this issue in my library, I would say the only way is to not put a copyWith in your base class.
Why? Because you should only make a function polymorphic when there IS actually a shared calling convention and behavior. In your example, The way that these two classes perform copyWith is just different. It is, and should be, an error to send a name to Manager.copyWith, because Manager does not have a name to begin with. If you encounter a name inside a Manager.copyWith, that means there is some serious error in your code.
Also, if you actually try to invoke copyWith, as a responsible programmer, you will probably check if you are allowed to pass a name, which is,
if (someObj is User) {
someObj.copyWith(key, name: name);
} else if (someObj is Manager) {
throw IllegalStateError('You should not pass a name to a Manager! What am I supposed to do with the name now?');
}
There, you have already done type checking, so no need to make copyWith polymorphic.
However, some common behaviors can be made polymorphic, like updateKey. You can make Keyable as an interface, and Keyable updateKey(Key key) as an abstract method, and delegate to a non-polymorphic copyWith inside each subclasses.
I have a class (OmeletteMaker) that contains an injected field (Vegetable). I would like to write a producer that instantiates an injected object of this class. If I use 'new', the result will not use injection. If I try to use a WeldContainer, I get an exception, since OmeletteMaker is #Alternative. Is there a third way to achieve this?
Here is my code:
#Alternative
public class OmeletteMaker implements EggMaker {
#Inject
Vegetable vegetable;
#Override
public String toString() {
return "Omelette: " + vegetable;
}
}
a vegetable for injection:
public class Tomato implements Vegetable {
#Override
public String toString() {
return "Tomato";
}
}
main file
public class CafeteriaMainApp {
public static WeldContainer container = new Weld().initialize();
public static void main(String[] args) {
Restaurant restaurant = (Restaurant) container.instance().select(Restaurant.class).get();
System.out.println(restaurant);
}
#Produces
public EggMaker eggMakerGenerator() {
return new OmeletteMaker();
}
}
The result I get is "Restaurant: Omelette: null", While I'd like to get "Restaurant: Omelette: Tomato"
If you provide OmeletteMaker yourself, its fields will not be injected by the CDI container. To use #Alternative, don't forget specifying it in the beans.xml and let the container instantiate the EggMaker instance:
<alternatives>
<class>your.package.path.OmeletteMaker</class>
</alternatives>
If you only want to implement this with Producer method then my answer may be inappropriate. I don't think it is possible (with standard CDI). The docs says: Producer methods provide a way to inject objects that are not beans, objects whose values may vary at runtime, and objects that require custom initialization.
Thanks Kukeltje for pointing to the other CDI question in comment:
With CDI extensions like Deltaspike, it is possible to inject the fields into an object created with new, simply with BeanProvider#injectFileds. I tested this myself:
#Produces
public EggMaker eggMakerProducer() {
EggMaker eggMaker = new OmeletteMaker();
BeanProvider.injectFields(eggMaker);
return eggMaker;
}
I'm relatively new to Guice, and some things still give me a pretty hard time.
My particular question is, how do you handle nested injections in Guice.
Example:
Class A uses Class B via #Inject, and Class B uses Class C.
Explicitly:
My Module where I bind to Providers.
public class ModuleBinder extends AbstractModule {
#Override
protected void configure() {
bind(DatabaseControllerInterface.class)
.toProvider(DatabaseControllerProvider.class).asEagerSingleton();
bind(AnalyzerInterface.class)
.toProvider(AnalyzerProvider.class).asEagerSingleton();
bind(SystemAdministrationInterface.class)
.toProvider(SystemAdministrationProvider.class).asEagerSingleton();
bind(LogInServiceInterface.class)
.toProvider(LogInServiceProvider.class);
}
}
The DatabaseControllerProvider:
public class DatabaseControllerProvider implements Provider<DatabaseControllerInterface> {
#Override
public DatabaseControllerInterface get() {
return new DatabaseControllerImpl();
}
}
The LogInServiceProvider:
public class LogInServiceProvider implements Provider<LogInServiceInterface> {
#Override
public LogInServiceInterface get() {
return new LogInServiceImpl();
}
}
And finally, the LogInService uses:
public class LogInServiceImpl implements LogInServiceInterface{
#Inject
private DatabaseControllerProvider databaseControllerProvider;
private final DatabaseControllerInterface databaseController;
public LogInServiceImpl() {
this.databaseController = databaseControllerProvider.get();
}
#Override
public User register(final String mail, final String userName, final String password) {
databaseController.registerUser(userName, mail, password, UserRole.ADMIN);
}
}
The call is then:
public class Test() {
public static test() {
final Injector injector = Guice.createInjector(new ModuleBinder());
logInService = injector.getInstance(LogInServiceInterface.class);
logInService.registerUser("test", "test", "test");
}
}
I know most of you guys will get sick with that code, but hey, I'm a beginner with Guice, so please be gentle with me.
I want to use Constructor injection, I already realized that field injection is considered "evil". Do you have any idea how to get that working by keeping the providers (I need them)?
Using the injections in the example does nothing on the "second" level, the DatabaseControllerImpl in LogInServiceImpl is null.
Did I configure something wrong? Did I misunderstand the usage of Provides and/or Modules?
I hope somebody can and wants to help me. If you need more informations, post a comment.
With best regards,
JosefRucksack
Your direct answer: You're calling new T(); in your Providers, which doesn't support field injection.
First, a real timesaver: Don't keep your explicit Providers. If you have bound a T, Guice allows you to inject a Provider or call Injector.getProvider for that T, even if you haven't explicitly created a Provider yourself. See the Built-In Bindings page on the wiki,
or the Injector docs (emphasis mine):
Contains several default bindings:
This Injector instance itself
A Provider<T> for each binding of type T
The Logger for the class being injected
The Stage in which the Injector was created
Instead, do it this way:
public class ModuleBinder extends AbstractModule {
#Override
protected void configure() {
bind(DatabaseControllerInterface.class)
.to(DatabaseControllerImpl.class).asEagerSingleton();
bind(AnalyzerInterface.class)
.to(AnalyzerImpl.class).asEagerSingleton();
bind(SystemAdministrationInterface.class)
.to(SystemAdministrationImpl.class).asEagerSingleton();
bind(LogInServiceInterface.class)
.to(LogInServiceImpl.class);
}
}
You then have the same choice you do now, to inject T or Provider<T> and call getInstance or getProvider as needed.
If your Providers are absolutely necessary, especially if they actually receive an instance from some other system or service locator, one other option is to add your #Inject fields into them as in the Provider bindings wiki page and pass them into your constructor, or to just inject a MembersInjector<T>:
public class LogInServiceProvider implements Provider<LogInServiceInterface> {
#Inject MembersInjector<LogInServiceImpl> logInServiceImplInjector;
#Override
public LogInServiceInterface get() {
LogInServiceImpl logInServiceImpl = YourExternalDep.getLogInService();
logInServiceImplInjector.injectMembers(logInServiceImpl);
return logInServiceImpl;
}
}
However, this explicit-Provider solution is not idiomatic Guice, and should only be used with external or legacy code. Guice's whole reason for existence is to automate away boilerplate and let your systems come together clearly and flexibly. Providers are an implementation detail; let Guice create them for you.
Overview
In Jersey 2, can I inject a custom, request-specific value into my resource? Specifically, I would like to inject a MyThing which can be derived from my custom security context MySecurityContext. I would like to inject MyThing directly to make the code clean.
Is there any way to do this? According to this question it can't be done using a ContextResolver although this article and this example suggest it might be possible.
What Works
Using an auth filter, I am able to set my custom security context using code like this:
#Provider
public class HttpTokenAuthFilter implements IComposableJaxRsAuthFilter {
#Override
public boolean doAuth(ContainerRequestContext requestContext) throws WebApplicationException {
// error handling omitted
requestContext.setSecurityContext(MySecurityContext.fromHeaders(requestContext));
}
}
... and then in my resource I can pull a value from it:
#Path("/foo")
public class MyResource {
#Context
private SecurityContext securityContext;
#Get
public String doGetFoo() {
MyThing myThing = ((MySecurityContext)securityContext).getThing();
// use myThing to produce a result
}
Where I'm Stuck
... however, since this is going to be repeated a lot, I would much rather just write:
#Context
private MyThing myThing;
I tried defining a ContextResolver. I see it getting constructed, but I never see it getting invoked, so I have not yet tried any of the techniques linked above. Is this even the correct class to be using?
#Provider
public class MyThingResolver implements ContextResolver<MyThing> {
public MyThingResolver() {
System.out.println("ctor");
}
#Override
public MyThing getContext(Class type) {
System.out.println("getContext");
if (type.equals(MyThing.class)) {
return new MyThing(); // TODO: SHOULD ACTUALLY USE CURRENT MySession
}
return null;
}
}
Almost the solution
Per this answer and the refinements specified at this followup, it's almost possible to accomplish the injection using a Factory. The only caveat is, you must inject MyThing via a Provider, otherwise it's going to get created (with the default SecurityContext) before the filter runs and swaps in the MySecurityContext.
The factory code looks like this:
public class MyThingFactory implements Factory<MyThing> {
#Context
private SecurityContext securityContext;
#Override
public MyThing provide() {
return ((MySecurityContext)securityContext).getThing();
}
#Override
public void dispose(MyThing session) {
}
}
The resource can then inject it like this:
#Context
private Provider<MyThing> myThingProvider;
... and consume it like this:
MyThing myThing = myThingProvider.get();
// use myThing
The factory registration in the AbstractBinder looks like this:
this.bindFactory(MyThingFactory.class) //
.to(MyThing.class) //
.in(RequestScoped.class);
(Edit) Proxies to the Rescue!
Per the comment from #peeskillet, it is possible to get rid of the Provider by proxying MyThing. (Per # jwells131313, MyThing must therefore be an interface or a proxy-able class.)
The binding then looks like this:
this.bindFactory(MyThingFactory.class) //
.to(MyThing.class) //
.proxy(true) //
.in(RequestScoped.class);
and injection finally works as desired:
#Context
private MyThing myThing;
I'm new to Guice and here is a naive question. I learned that we could bind String to a particular value through:
bind(String.class)
.annotatedWith(Names.named("JDBC URL"))
.toInstance("jdbc:mysql://localhost/pizza");
But what if I want to bind String to any possible characters?
Or I think it could be described this way:
How can I replace "new SomeClass(String strParameter)" with Guice?
You first need to annotate the constructor for SomeClass:
class SomeClass {
#Inject
SomeClass(#Named("JDBC URL") String jdbcUrl) {
this.jdbcUrl = jdbcUrl;
}
}
I prefer to use custom annotations, like this:
class SomeClass {
#Inject
SomeClass(#JdbcUrl String jdbcUrl) {
this.jdbcUrl = jdbcUrl;
}
#Retention(RetentionPolicy.RUNTIME)
#Target({ElementType.FIELD, ElementType.PARAMETER})
#BindingAnnotation
public #interface JdbcUrl {}
}
Then you need to provide a binding in your Module:
public class SomeModule extends AbstractModule {
private final String jdbcUrl; // set in constructor
protected void configure() {
bindConstant().annotatedWith(SomeClass.JdbcUrl.class).to(jdbcUrl);
}
}
Then an time Guice creates SomeClass, it will inject the parameter. For instance, if SomeOtherClass depends on SomeClass:
class SomeOtherClass {
#Inject
SomeOtherClass(SomeClass someClass) {
this.someClass = someClass;
}
Often, when you think you want to inject a String, you want to inject an object. For instance, if the String is a URL, I often inject a URI with a binding annotation.
This all assumes there is some constant value you can define at module creation time for the String. If the value isn't available at module creation time, you can use AssistedInject.
This might be off-topic, but Guice makes configuration much easier than writing an explicit binding for every String you need. You can just have a config file for them:
Properties configProps = Properties.load(getClass().getClassLoader().getResourceAsStream("myconfig.properties");
Names.bindProperties(binder(), configProps);
and voilà all your config is ready for injection:
#Provides // use this to have nice creation methods in modules
public Connection getDBConnection(#Named("dbConnection") String connectionStr,
#Named("dbUser") String user,
#Named("dbPw") String pw,) {
return DriverManager.getConnection(connectionStr, user, pw);
}
Now just create your Java properties file myconfig.properties at the root of your classpath with
dbConnection = jdbc:mysql://localhost/test
dbUser = username
dbPw = password
or merge authorization information from some other source into the properties and you're set.
I was able to inject a string through Named annotation.
#Provides
#Named("stage")
String stage() {
return domain;
}
class SomeClass {
#Inject
#Named("stage")
String stageName;
}
I find a solution in the FAQ of Guice:
http://code.google.com/docreader/#p=google-guice&s=google-guice&t=FrequentlyAskedQuestions
In addition to define an annotation and a String attribute in MyModule, I need to write below line to get a instance of SomeClass:
SomeClass instance = Guice.createInjector(new MyModule("any string i like to use")).getInstance(SomeClass.class);
But I remembered that Injector.getInstance() should not be used except for the root object, so is there any better way to do this?