I am having difficulty with Spring-Camel getting a HeaderFilterStrategy class registered as a Bean so it can be found by the Camel Route. My attempts to annotate the HeaderFilterStrategy custom class seem futile... so how do I register this thing so it gets found at run time?
I have a camel application with a route utilizing a custom HeaderFilterStrategy
The Strategy Class looks like :
public class HeaderFilter implements HeaderFilterStrategy {
#Override
public boolean applyFilterToCamelHeaders(String s, Object o, Exchange exchange) {
return false;
}
#Override
public boolean applyFilterToExternalHeaders(String s, Object o, Exchange exchange) {
return true;
}
}
I register it with camel using a simple registry:
SimpleRegistry registry = new SimpleRegistry();
registry.put("HeaderFilter" ,new HeaderFilter());
.
.
final CamelContext ctx = new DefaultCamelContext(registry);
And I reference it in my Route in
.to("https://myhost/endpoint&headerFilterStrategy=#HeaderFilter")
And all like Ralphy on Christmas night with his trusty Red Rider BB Gun, all is right with the world.
So, now I am trying to take this pure camel app and put it under Spring. I make sure all the appropriate Camel, and Spring-Camel and Spring things are imported.. However, when I attempt to annotate my HeaderStrategy as a Bean for Spring and it fails:
#Component
public class HeaderFilter implements HeaderFilterStrategy {
#Bean
#Override
public boolean applyFilterToCamelHeaders(String s, Object o, Exchange exchange) {
return false;
}
#Override
public boolean applyFilterToExternalHeaders(String s, Object o, Exchange exchange) {
return true;
}
}
Now when I do this, the IDE basically tells me it can't autowire any of the parameters in the method calls becaue there is more than one bean of type String or Object and no beans of type Exchange found..
At Runtime, Camel does attempt to interpret the route, but throws a failure with "No Qualifying bean type of "java.lang.String" available, since this is the first parameter in the method call...
So, How do I get this thing to be able register with annotations correctly? Or manually register this bean without it attempting to autowire? All I need is the class to be registered as a BEAN so it can be found by camel at runtime... Or at least that is what I understand needs to happen... so how the heck to I do this?
I figured it out, I was not properly using the annotationsI added the following to my AppConfig class:
#Configuration
public class AppConfig{
#Bean
public HeaderFilter HeaderFilter(){
return new HeaderFilter();
}
}
I am not sure if the suggestion above will work, but this clearly does.
Related
I am using Spring AOP to fire metrics in our application. I have created an annotation #CaptureMetrics which has an #around advice associated with it. The advice is invoked fine from all the methods tagged with #CaptureMetrics except for a case when a method is invoked on a prototype bean.
The annotation has #Target({ElementType.TYPE, ElementType.METHOD})
PointCut expression:
#Around(value = "execution(* *.*(..)) && #annotation(captureMetrics)",
argNames = "joinPoint,captureMetrics")
Prototype bean creation
#Bean
#Scope(ConfigurableBeanFactory.SCOPE_PROTOTYPE)
public DummyService getDummyServicePrototypeBean(int a, String b) {
return new DummyService(a, b);
}
DummyService has a method called dummyMethod(String dummyString)
#CaptureMetrics(type = MetricType.SOME_TYPE, name = "XYZ")
public Response dummyMethod(id) throws Exception {
// Do some work here
}
When dummyService.dummyMethod("123") is invoked from some other service, the #Around advice is not called.
Config class
#Configuration
public class DummyServiceConfig {
#Bean
public DummyServiceRegistry dummyServiceRegistry(
#Value("${timeout}") Integer timeout,
#Value("${dummy.secrets.path}") Resource dummySecretsPath) throws IOException {
ObjectMapper mapper = new ObjectMapper();
Map<String, String> transactionSourceToTokens = mapper.readValue(
dummySecretsPath.getFile(), new TypeReference<Map<String, String>>() {
});
DummyServiceRegistry registry = new DummyServiceRegistry();
transactionSourceToTokens.forEach((transactionSource, token) ->
registry.register(transactionSource,
getDummyServicePrototypeBean(timeout, token)));
return registry;
}
#Bean
#Scope(ConfigurableBeanFactory.SCOPE_PROTOTYPE)
public DummyService getDummyServicePrototypeBean(int a, String b) {
return new DummyService(a, b);
}
}
Singleton Registry class
public class DummyServiceRegistry {
private final Map<String, DummyService> transactionSourceToService = new HashMap<>();
public void register(String transactionSource, DummyService dummyService) {
this.transactionSourceToService.put(transactionSource, dummyService);
}
public Optional<DummyService> lookup(String transactionSource) {
return Optional.ofNullable(transactionSourceToService.get(transactionSource));
}
}
Any advice on this please?
Note:
The prototype Dummy service is used to call a third party client. It is a prototype bean as it has a state that varies based on whose behalf it is going to call the third party.
A singleton registry bean during initialization builds a map of {source_of_request, dummyService_prototype}. To get the dummyService prototype it calls getDummyServicePrototypeBean()
The configuration, registry and prototype dummy bean were correct.
I was testing the flow using an existing integration test and there instead of supplying a prototype Bean, new objects of DummyService were instantiated using the new keyword. It wasn't a spring managed bean.
Spring AOP works only with Spring managed beans.
I can't find a simple way to inject a component/service given a runtime value.
I started reading # Spring's doc: http://docs.spring.io/spring/docs/current/spring-framework-reference/html/beans.html#beans-autowired-annotation-qualifiers
but I can't find there how to variabilize the values passed to the #Qualifier annotation.
Let's say I've got a model entity with such interface:
public interface Case {
String getCountryCode();
void setCountryCode(String countryCode);
}
In my client code, I would do something like:
#Inject
DoService does;
(...)
Case myCase = new CaseImpl(); // ...or whatever
myCase.setCountryCode("uk");
does.whateverWith(myCase);
... with my service being:
#Service
public class DoService {
#Inject
// FIXME what kind of #$#& symbol can I use here?
// Seems like SpEL is sadly invalid here :(
#Qualifier("${caze.countryCode}")
private CaseService caseService;
public void whateverWith(Case caze) {
caseService.modify(caze);
}
}
I expect the caseService to be the UKCaseService (see related code below).
public interface CaseService {
void modify(Case caze);
}
#Service
#Qualifier("uk")
public class UKCaseService implements CaseService {
}
#Service
#Qualifier("us")
public class USCaseService implements CaseService {
}
So how do I "fix" all of this in the most simple / elegant / efficient way by using either/all Spring feature(s), so essentially NO .properties, NO XML, only annotations.
However I already suspect something is wrong in my DoService because Spring would need to know the "case" before injecting the caseService... but how to achieve this without the client code knowing about the caseService?!
I can't figure this out...
I already read several issues here on SO, but most of the times either they don't really have the same needs and/or config as I have, or the posted answers aren't enough satisfying to me (look like they're essentially workarounds or (old) usage of (old) Spring features).
How does Spring autowire by name when more than one matching bean is found?
=> only refers to component-like classes
Dynamically defining which bean to autowire in Spring (using qualifiers)
=> really interesting but the most elaborated answer (4 votes) is... almost 3 1/2 years-old?! (July 2013)
Spring 3 - Dynamic Autowiring at runtime based on another object attribute
=> quite similar problem here, but the answer really look like a workaround rather a real design pattern (like factory)? and I don't like implementing all the code into the ServiceImpl as it's done...
Spring #Autowiring, how to use an object factory to choose implementation?
=> 2nd answer seems interestingly but its author does not expand, so altough I know (a bit) about Java Config & stuff, I'm not really sure what he's talking about...
How to inject different services at runtime based on a property with Spring without XML
=> interesting discussion, esp. the answer, but the user has properties set, which I don't have.
Also read this:
http://docs.spring.io/spring/docs/current/spring-framework-reference/html/expressions.html#expressions-bean-references
=> I can't find expanded examples about the use of "#" in expressions. Does someone know about this?
Edit:
Found other related-to-similar issues, no one got a proper answer:
How to use #Autowired to dynamically inject implementation like a factory pattern
Spring Qualifier and property placeholder
Spring: Using #Qualifier with Property Placeholder
How to do conditional auto-wiring in Spring?
Dynamic injection in Spring
SpEL in #Qualifier refer to same bean
How to use SpEL to inject result of method call in Spring?
Factory Pattern might be a solution?
How to use #Autowired to dynamically inject implementation like a factory pattern
You can obtain your bean from the context by name dynamically using a BeanFactory:
#Service
public class Doer {
#Autowired BeanFactory beans;
public void doSomething(Case case){
CaseService service = beans.getBean(case.getCountryCode(), CaseService.class)
service.doSomething(case);
}
}
A side note. Using something like country code as bean name looks a bit odd. Add at least some prefix or better consider some other design pattern.
If you still like to have bean per country, I would suggest another approach. Introduce a registry service to get a required service by country code:
#Service
public class CaseServices {
private final Map<String, CaseService> servicesByCountryCode = new HashMap<>();
#Autowired
public CaseServices(List<CaseService> services){
for (CaseService service: services){
register(service.getCountryCode(), service);
}
}
public void register(String countryCode, CaseService service) {
this.servicesByCountryCode.put(countryCode, service);
}
public CaseService getCaseService(String countryCode){
return this.servicesByCountryCode.get(countryCode);
}
}
Example usage:
#Service
public class DoService {
#Autowired CaseServices caseServices;
public void doSomethingWith(Case case){
CaseService service = caseServices.getCaseService(case.getCountryCode());
service.modify(case);
}
}
In this case you have to add String getCountryCode() method to your CaseService interface.
public interface CaseService {
void modify(Case case);
String getCountryCode();
}
Alternatively, you can add method CaseService.supports(Case case) to select the service. Or, if you cannot extend the interface, you can call CaseServices.register(String, CaseService) method from some initialiser or a #Configuration class.
UPDATE: Forgot to mention, that Spring already provides a nice Plugin abstraction to reuse boilerplate code for creating PluginRegistry like this.
Example:
public interface CaseService extends Plugin<String>{
void doSomething(Case case);
}
#Service
#Priority(0)
public class SwissCaseService implements CaseService {
void doSomething(Case case){
// Do something with the Swiss case
}
boolean supports(String countryCode){
return countryCode.equals("CH");
}
}
#Service
#Priority(Ordered.LOWEST_PRECEDENCE)
public class DefaultCaseService implements CaseService {
void doSomething(Case case){
// Do something with the case by-default
}
boolean supports(String countryCode){
return true;
}
}
#Service
public class CaseServices {
private final PluginRegistry<CaseService<?>, String> registry;
#Autowired
public Cases(List<CaseService> services){
this.registry = OrderAwarePluginRegistry.create(services);
}
public CaseService getCaseService(String countryCode){
return registry.getPluginFor(countryCode);
}
}
According to this SO answer, using #Qualifier isn't going to help you much: Get bean from ApplicationContext by qualifier
As for an alternative strategy:
if you are spring boot, you could use #ConditonalOnProperty or another Conditional.
a lookup service, as #aux suggests
just name your beans consistently and look them up by name at runtime.
Note that your use case also appears to revolve around the scenario where beans are created on application startup, but the bean chosen needs to be resolved after the applicationContext has finished injecting the beans.
I'm trying to disable a Zuul route to a microservice registered with Eureka at runtime (I'm using spring boot).
This is an example:
localhost/hello
localhost/world
Those two are the registered microservices. I would like to disable the route to one of them at runtime without shutting it down.
Is there a way to do this?
Thank you,
Nano
Alternatively to using Cloud Config, custom ZuulFilter can be used. Something like (partial implementation to show the concept):
public class BlackListFilter extends ZuulFilter {
#Override
public String filterType() {
return "pre";
}
...
#Override
public Object run() {
RequestContext ctx = RequestContext.getCurrentContext();
String uri = ctx.getRequest().getRequestURI();
String appId = uri.split("/")[1];
if (blackList.contains(appId)) {
ctx.setSendZuulResponse(false);
LOG.info("Request '{}' from {}:{} is blocked",
uri, ctx.getRequest().getRemoteHost(), ctx.getRequest().getRemotePort());
}
return null;
}
}
where blackList contains list of application IDs (Spring Boot application name) managed for example via some RESTful API.
After a lot of efforts I came up with this solution. First, I used Netflix Archaius to watch a property file. Then I proceeded as follows:
public class ApplicationRouteLocator extends SimpleRouteLocator implements RefreshableRouteLocator {
public ApplicationRouteLocator(String servletPath, ZuulProperties properties) {
super(servletPath, properties );
}
#Override
public void refresh() {
doRefresh();
}
}
Made the doRefresh() method public by extending SimpleRouteLocator and calling its method in the overridden one of the interface RefreshableRouteLocator.
Then I redefined the bean RouteLocator with my custom implementation:
#Configuration
#EnableConfigurationProperties( { ZuulProperties.class } )
public class ZuulConfig {
public static ApplicationRouteLocator simpleRouteLocator;
#Autowired
private ZuulProperties zuulProperties;
#Autowired
private ServerProperties server;
#Bean
#Primary
public RouteLocator routeLocator() {
logger.info( "zuulProperties are: {}", zuulProperties );
simpleRouteLocator = new ApplicationRouteLocator( this.server.getServletPrefix(),
this.zuulProperties );
ConfigurationManager.getConfigInstance().addConfigurationListener( configurationListener );
return simpleRouteLocator;
}
private ConfigurationListener configurationListener =
new ConfigurationListener() {
#Override
public void configurationChanged( ConfigurationEvent ce ) {
// zuulProperties.getRoutes() do something
// zuulProperties.getIgnoredPatterns() do something
simpleRouteLocator.refresh();
}
}
}
Every time a property in the file was modified an event was triggered and the ConfigurationEvent was able to deal with it (getPropertyName() and getPropertyValue() to extract data from the event). Since I also Autowired the ZuulProperties I was able to get access to it. With the right rule I could find whether the property of Zuul
zuul.ignoredPatterns
was modified changing its value in the ZuulProperties accordingly.
Here refresh context should work (as long as you are not adding a new routing rule or removing a currently existing one), if you are adding or removing routing rules, you have to add a new bean for ZuulProperties and mark it with #RefreshScope, #Primary.
You can autowire refreshEndpoint bean for example and apply refreshEndpoint.refresh() on the listener.
Marking a custom RouteLocator as primary will cause problems as zuul already has bean of same type marked as primary.
I've seen one of the program where MyConfig(Spring Configuration file) is being referenced in constructor of one of the bean in order to get other bean defined in MyConfig.
I am not sure about this kind of configuration. I can see cyclic reference in this kind of code, though it is working fine but I am not able to understand the flow. How it is working. Below is the replica of that code -
#Configuration
public class MyConfig {
#Bean(name="a")
#Scope("prototype")
public A getA() {
return new A();
}
#Bean(name="b")
#Scope("prototype")
public B getB() {
return new B();
}
#Bean(name="c")
#Scope("prototype")
public C getC() {
return new C();
}
#Bean(name="queueListener")
#Scope("singleton")
public Queue getQueue() {
return new Queue(MyConfig config);
}
}
Here is my Queue class -
public class Queue implements MessageListener{
private MyConfig config;
public Q(MyConfig config) {
this.config = config;
}
#Override
public void onMessage() {
createC();
}
public void createC() {
C cObj = config.getC();
cObj.setConfig(config);
cObj.performTask();
}
}
The class is "C" look like this-
public class C{
private transient MyConfig config;
private MyConfig config;
public C() {
}
public void setConfig(MyConfig config) {
this.config = config;
}
public MyConfig getConfig() {
return config;
}
public void performTask() {
A a = config.getA(); // Is it right way to get bean?
B b = config.getB();
}
}
So my question is that is it right way to get bean in another bean?
Will the return object really be spring bean object or simple java class object?
I can see cyclic reference in above code cause When instance of Queue class will be created inside MyConfig will take instance/reference of MyConfig.
Will this create cyclic reference?
My Architect has suggested me above approach instead of autoWiring Application context in both classes Queue and class "C". According to architect context is very heavy and it is not best practice.
What will be the execution cycle or call hierarchy when bean Queue is getting created?
It would be very much helpful to understand the working of above code.
It is a really bad idea to inject the configuration instance into a specific bean. It complicates your code and makes it inconvenient for testing because for testing Queue instance you should somehow mock the whole configuration.
If you want to inject a prototype bean to the singleton you can use a technique described here :
Howto generate prototype objects with in a singleton bean using spring java configurations
Please see example at Spring Boot #Autowired creating instances on a runtime
You can see how to use singleton and prototypes right way
I have a project where I have an interface, an Abstract class implementing the same interface and then a set of concrete classes which implement this interface and extend the Abstract Class.
public interface Invoice
{
void process();
}
#component
public abstract class AbstractInvoice(){
#Resource
protected Writer writer;
protected validateInvoice(){
//some implementation
}
}
#Component
public Class TypeAInvoice() extends AbstractInvoice implements Invoice{
#Override
public void process(){
//... some code
writer.write();
}
}
public Interface Writer(){
public void write();
}
#Component
public class CDWriter implements Writer{
#Override
public void write() { /* implementation.....*/}
}
Spring file has a component scan for the package.
<context:annotation-config>
<context:component-scan base-package="com.xyz" />
I am using a factory to get an instance of TypeAInvoice invoice
Now calling invoice.process() gets a NPE when getting to write.write()
I am not sure what am I missing here. I tried to see the component scan and scope and could not find anything conceptually wrong.
I am using a factory to get an instance of TypeAInvoice invoice
Depending on what your Factory does, this may be the problem. If the Factory creates a new TypeAInvoice, Spring wiring doesn't apply. You have to query the Spring context for the Bean. One way (though not very pretty) is to use ContextLoader:
return ContextLoader.getCurrentWebApplicationContext().getBean(TypeAInvoice.class)
I'd say static Factories and Spring don't go to well together. Spring stands for the Inversion of Control pattern, while Factories stand for the Service Locator pattern. I'd suggest that you get rid of your factories and autowire your Spring Beans.
Everything is good, except for the fact you use a factory to get the TypeAInvoice. If you create it like TypeAInvoice typer = new TypeAInvoice() then spring knows nothing of it, the Writer is not autowired, there for you get the NullPointerException. You should get the bean from the spring application context.
In my case, inside a Spring4 Application, i had to use a classic Abstract Factory Pattern(for which i took the idea from - http://java-design-patterns.com/patterns/abstract-factory/) to create instances each and every time there was a operation to be done.So my code was to be designed like:
public abstract class EO {
#Autowired
protected SmsNotificationService smsNotificationService;
#Autowired
protected SendEmailService sendEmailService;
...
protected abstract void executeOperation(GenericMessage gMessage);
}
public final class OperationsExecutor {
public enum OperationsType {
ENROLL, CAMPAIGN
}
private OperationsExecutor() {
}
public static Object delegateOperation(OperationsType type, Object obj)
{
switch(type) {
case ENROLL:
if (obj == null) {
return new EnrollOperation();
}
return EnrollOperation.validateRequestParams(obj);
case CAMPAIGN:
if (obj == null) {
return new CampaignOperation();
}
return CampaignOperation.validateRequestParams(obj);
default:
throw new IllegalArgumentException("OperationsType not supported.");
}
}
}
#Configurable(dependencyCheck = true)
public class CampaignOperation extends EO {
#Override
public void executeOperation(GenericMessage genericMessage) {
LOGGER.info("This is CAMPAIGN Operation: " + genericMessage);
}
}
Initially to inject the dependencies in the abstract class I tried all stereotype annotations like #Component, #Service etc but even though Spring context file had ComponentScanning for the entire package, but somehow while creating instances of Subclasses like CampaignOperation, the Super Abstract class EO was having null for its properties as spring was unable to recognize and inject its dependencies.After much trial and error I used this **#Configurable(dependencyCheck = true)** annotation and finally Spring was able to inject the dependencies and I was able to use the properties in the subclass without cluttering them with too many properties.
<context:annotation-config />
<context:component-scan base-package="com.xyz" />
I also tried these other references to find a solution:
http://www.captaindebug.com/2011/06/implementing-springs-factorybean.html#.WqF5pJPwaAN
http://forum.spring.io/forum/spring-projects/container/46815-problem-with-autowired-in-abstract-class
https://github.com/cavallefano/Abstract-Factory-Pattern-Spring-Annotation
http://www.jcombat.com/spring/factory-implementation-using-servicelocatorfactorybean-in-spring
https://www.madbit.org/blog/programming/1074/1074/#sthash.XEJXdIR5.dpbs
Using abstract factory with Spring framework
Spring and Abstract class - injecting properties in abstract classes
Inject spring dependency in abstract super class
Spring autowire dependency defined in an abstract class
Spring can you autowire inside an abstract class?
Please try using **#Configurable(dependencyCheck = true)** and update this post, I might try helping you if you face any problems.
So precisely my point here is you don't need to get a bean from spring context all the time.