I want to create a custom spring annotation which will work under some conditions or parameters. But as a business constraint I need to share the library which has Genre annotation to all my applications. Is it possible to configure my annotation for limiting to some of my applications like #Profile annotation?
#Target({ElementType.FIELD, ElementType.PARAMETER}) #Retention(RetentionPolicy.RUNTIME)
#Qualifier
public #interface Genre {
String value();
}
and its usage
public class MovieRecommender {
#Autowired
#Genre("Action")
private MovieCatalog actionCatalog;
private MovieCatalog comedyCatalog;
#Autowired
public void setComedyCatalog(#Genre("Comedy") MovieCatalog comedyCatalog) {
this.comedyCatalog = comedyCatalog;
}
// ...
}
I don't think it is possible to alter the behaviour of #Autowired annotation.
However you can easily implement your own BeanPostProcessor and use all the convenience Spring classes, such as AnnotationUtils, ReflectionUtils, etc.
On one project we needed custom JAX-WS port injection. So we created #InjectedPort annotation and implemented our own InjectedPortAnnotationBeanPostProcessor (this just illustrates the simplicity of custom injection logic, the purpose of the code itself is unrelated to the question):
#Override
public Object postProcessBeforeInitialization(final Object bean, String beanName) {
// Walk through class fields and check InjectedPort annotation presence
ReflectionUtils.doWithFields(bean.getClass(), new FieldCallback() {
#Override
public void doWith(final Field field) {
// Find InjectedPort annotation
final InjectedPort injectedPort = field.getAnnotation(InjectedPort.class);
if (injectedPort == null) {
return; // Annotation is not present
}
// Get web service class from the annotation parameter
Class<?> serviceClass = injectedPort.value();
// Find web service annotation on the specified class
WebServiceClient serviceAnnotation = AnnotationUtils.findAnnotation(serviceClass, WebServiceClient.class);
if (serviceAnnotation == null) {
throw new IllegalStateException("Missing WebService " + "annotation on '" + serviceClass + "'.");
}
// Get web service instance from the bean factory
Service service = (Service) beanFactory.getBean(serviceClass);
// Determine the name of the JAX-WS port
QName portName = new QName(service.getServiceName().getNamespaceURI(), findPortLocalName(serviceClass, field.getType()));
// Obtain the JAX-WS port
Object port = service.getPort(portName, field.getType());
// Inject the port into the target bean
ReflectionUtils.makeAccessible(field);
ReflectionUtils.setField(field, bean, port);
}
});
return bean;
}
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 would like to understand what is the programmatic equivalent of a #Bean annotated bean registration
Lets say i have a class like this:
#Configuration
public class SimpleConfiguration {
#Bean
public BigDecimal aDecimal( String example ) {
return new BigDecimal( example );
}
}
here is what i think happens here:
somehow spring register this method as a factory for a bean named
"aDecimal" of type BigDecimal, with a dependency on a bean of type
String
at some point this method will be called with the right bean as
parameter and the result will be the instance associated to the
"aDecimal" bean.
If i wanted to do the same with something like this:
#Configuration
public class DynamicConfiguration {
public void registerDefinition() {
/* i know it can't be like this but i hope it's clear what i mean */
register( "aDecimal", (example) -> aDecimal( example ) );
}
public BigDecimal aDecimal( String example ) {
/* this could be any kind of complex bean creation method */
return new BigDecimal( example );
}
}
what would be the right way to achieve this result?
i already researched a bit about this, and i found for example
How do I create beans programmatically in Spring Boot?
but this kind of registration doesn't seem as powerful as the annotation, and let's spring instatiate the bean, i want the bean to be instatied by a provided method
How to programmatically create bean definition with injected properties?
and this is missing the ability to call a method with injected bean parameters.
the reason i want to do this, is that i have some configuration classes that hold a lot of the same kind of beans with different qualifiers, based on a configuration file.
now every time the configuration file expands, i need to add new beans and configurations ( many of these are spring SessionFactories and SpringIntegration flows so i need these things to be spring beans )
You need to consider to use IntegrationFlowContext:
#Autowired
private IntegrationFlowContext integrationFlowContext;
...
IntegrationFlow myFlow = f -> ...;
BeanFactoryHandler additionalBean = new BeanFactoryHandler();
IntegrationFlowRegistration flowRegistration =
this.integrationFlowContext.registration(myFlow)
.addBean(additionalBean)
.register();
It provides for you hooks to register additional beans at runtime, not only IntegrationFlow structure.
I found the way to solve my problem, it all happens in the BeanDefinition "phase" this way everything is managed by spring and works exactly the same as as a #Bean annotated method with injected parameters, it also cleanly bridge between annotated and programmatically registered beans.
here is what i did
#Configuration
#RunWith( SpringJUnit4ClassRunner.class )
#ContextConfiguration( classes = { TestSpringDynamicConfiguration.class } )
public class TestSpringDynamicConfiguration implements BeanDefinitionRegistryPostProcessor {
#Autowired
#Qualifier( "qualified" )
private String dynamicString;
#Bean
public Integer zero() {
return 0;
}
public String zeroString( Integer aInteger ) {
return aInteger.toString();
}
#Override
public void postProcessBeanDefinitionRegistry( final BeanDefinitionRegistry registry ) throws BeansException {
GenericBeanDefinition beanDefinition = new GenericBeanDefinition();
beanDefinition.setAutowireMode( GenericBeanDefinition.AUTOWIRE_CONSTRUCTOR );
beanDefinition.setScope( BeanDefinition.SCOPE_SINGLETON );
beanDefinition.setFactoryBeanName( "testSpringDynamicConfiguration" );
beanDefinition.setFactoryMethodName( "zeroString" );
registry.registerBeanDefinition( "qualified", beanDefinition );
}
#Override public void postProcessBeanFactory( final ConfigurableListableBeanFactory beanFactory ) throws BeansException { }
#Test
public void testDynamicConfiguration() throws Exception {
assertThat( dynamicString, is( "0" ) );
}
}
I have a instance of a class that is created outside of Spring that I'd like to have access to Spring beans so that it may fire an event and be observed by Spring beans. I'm not using Spring web, my application is running from the command-line via spring boot.
The only option you have is to expose the Spring context of your application using a static method so that the object that is not managed by Spring can use it to get references to managed beans it needs.
Start with a wrapper for the context. Create a regular managed bean which required reference to the context in its constructor. The reference is assigned to a static class field, which also has a static getter:
#Service
class ContextWrapper {
private static ApplicationContext context;
#Autowired
public ContextWrapper(ApplicationContext ac) {
context = ac;
}
public static ApplicationContext getContext() {
return context;
}
}
Use the static getter to get access to context in the object which is not managed by Spring and get reference to beans using methods available in the context:
SomeBean bean = ContextWrapper.getContext().getBean("someBean", SomeBean.class);
// do something with the bean
Last thing you need is communication channel from Spring beans to non-managed object. For instance, the SomeBean can expose a setter which will accept the non-managed object as a parameter and store the reference in a field for future use. The object mast get references to managed beans using the static context accessor mentioned above and use the setter to make the bean aware of its existence.
#Service
class SomeBean {
// ... your bean stuff
private SomeClass someclass;
public void setSomeClass(Someclass someclass) {
this.someclass = someclass;
}
private void sendEventToSomeClass() {
// communicate with the object not managed by Spring
if (someClass == null) return;
someClass.sendEvent();
}
}
You can inject by constructor that spring beans, something like:
#Service
class Bean {
...
}
class NotBean {
private Bean bean;
public NotBean(Bean bean) {
this.bean = bean;
}
// your stuff (handle events, etc...)
}
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.
In a spring based project I am working on, there's a layer of functionality for calling web service. For each web service operation, a method is created with almost same code but with some different, operation specific, information(e.g. service name, operation name, namespaces, etc).
I am replacing this layer with interfaces and annotated methods. For example, below code is provided for operation "fetchBar" of web service("foo").
package a.b.c.webservices;
#WebService(service="foo", namespace="...")
public interface FooWebService {
#WebServiceOperation(operation="fetchBar")
BarRespons fetchBar(BarRequest request) throws WebServiceException;
}
Now I want, with some mechanism, spring allow me to create dynamic proxy beans from some specified package(s) and I can use following code to call web service.
package a.b.c.business;
import a.b.c.webservices.FooWebService;
public class FooBusiness {
#Autowired
FooWebService fooWebService;
public Bar getBar() {
Bar bar = null;
BarRequest request;
//create request
BarResponse response = fooWebService.fetchBar(request);
//extrac bar from response
return bar;
}
}
To achieve this I have created dynamic beans instances using java.lang.reflect.Proxy.newProxyInstance by providing it implementation of InvocationHandler. But Autowiring doesn't work in provided implementation of invocationHandler and in its further dependencies.
I tried following ways to achieve this.
Implemented BeanFactoryPostProcessor.postProcessBeanFactory and registered beans using ConfigurableListableBeanFactory.registerSingleton method.
Implemented ImportBeanDefinitionRegistrar.registerBeanDefinitions and tried to use BeanDefinitionRegistry.registerBeanDefinition but I am confused how to provide correct Bean definition that supports Autowiring.
Can any one tell me what is missing? Please guide me if I am not going in right direction.
Here's how I implemented all the functionality that creates beans of 'WebService' annotated interfaces and also supports Autowiring inside proxy implementation. (package declaration and import statements are omitted in below code)
First of all I created WebService and WebServiceOperation annotation.
WebService Annotation
#Target(ElementType.TYPE)
#Retention(RetentionPolicy.RUNTIME)
public #interface WebService {
String service();
String namespace();
}
WebService Operation Annotation
#Target(ElementType.METHOD)
#Retention(RetentionPolicy.RUNTIME)
public #interface WebServiceOperation {
String operation();
}
Next step is to scan all WebService annotated interfaces from specified packages. Spring provides ClassPathScanningCandidateComponentProvider for package scanning but it does not detect interfaces. Please see this question and it's answer for more details. So I extended ClassPathScanningCandidateComponentProvider and overrode isCandidateComponent method.
ClassPathScanner
public class ClassPathScanner extends ClassPathScanningCandidateComponentProvider {
public ClassPathScanner(final boolean useDefaultFilters) {
super(useDefaultFilters);
}
#Override
protected boolean isCandidateComponent(AnnotatedBeanDefinition beanDefinition) {
return beanDefinition.getMetadata().isIndependent();
}
}
At this point I created EnableWebServices annotation to enable web services and to provide web service packages that contain WebService annotated interfaces.
EnableWebServices Annotation
#Retention(RetentionPolicy.RUNTIME)
#Target(ElementType.TYPE)
#Import({
WebServiceProxyConfig.class,
WebServiceProxyBeansRegistrar.class
})
public #interface EnableWebServices {
#AliasFor("basePackages")
String[] value() default {};
#AliasFor("value")
String[] basePackages() default {};
}
This annotation can be applied to some Configuration annotated class with packages to scan interfaces, as below.
#EnableWebServices({
"a.b.c.webservices",
"x.y.z.webservices"
})
It's time to think about dynamic proxy creation that will invoke actual web service from information given in WebService and WebServiceOperation annotations. Java provides a mechanism to create dynamic proxy which requires to provide implementation of InvocationHandler interface and provide logic in its invoke method. I named this implementaiton as WebServiceProxy
Suppose a bean of type 'TheWebServiceCaller' contains all nasty logic to call a web service. I just have inject it and to invoke it's call method with a TheWebServiceInfo (extracted from WebService and WebServiceOperation annotations) and request object.
TheWebServiceInfo(Suppose all fields have getters and setters)
public class TheWebServiceInfo {
private String service;
private String namespace;
private String operation;
}
WebServiceProxy
public class WebServiceProxy implements InvocationHandler {
#Autowired
private TheWebServiceCaller caller;
#Override
public Object invoke(Object target, Method method, Object[] args) throws Exception {
Object request = (null != args && args.length > 0) ? args[0] : null;
WebService webService = method.getDeclaringClass().getAnnotation(WebService.class);
WebServiceOperation webServiceOperation = method.getAnnotation(WebServiceOperation.class);
TheWebServiceInfo theInfo = createTheWebServiceInfo(webService, webServiceOperation);
return caller.call(theInfo, request);
}
private TheWebServiceInfo createTheWebServiceInfo(WebService webService, WebServiceOperation webServiceOperation) {
TheWebServiceInfo theInfo = new TheWebServiceInfo();
theInfo.setService(webService.service());
theInfo.setNamespace(webService.namespace());
theInfo.setOperation(webServiceOperation.operation());
return theInfo;
}
}
Implementaion of InvocationHandler is passed to Proxy.newProxyInstance (along with some other information) to create proxy objects. I need separat proxy objectes for each WebService annotated interface. I will now create a factory to proxy instances creation and name is as 'WebServiceProxyBeanFactory'. Instances created by this factory will become beans for corresponding WebService annotated interfaces.
A bit later, I will expose 'WebServiceProxy' and WebServiceProxyBeanFactory as beans. In 'WebServiceProxyBeanFactory', I will inject WebServiceProxy and used it. Please note that createWebServiceProxyBean uses generics. This is important.
WebServiceProxyBeanFactory
public class WebServiceProxyBeanFactory {
#Autowired
WebServiceProxy webServiceProxy;
#SuppressWarnings("unchecked")
public <WS> WS createWebServiceProxyBean(ClassLoader classLoader, Class<WS> clazz) {
return (WS) Proxy.newProxyInstance(classLoader, new Class[] {clazz}, webServiceProxy);
}
}
If you remember, earlier I have imported WebServiceProxyConfig in EnableWebServices annotations. WebServiceProxyConfig is used to expose WebServiceProxy and WebServiceProxyBeanFactory as beans.
WebServiceProxyConfig
#Configuration
public class WebServiceProxyConfig {
#Bean
public WebServiceProxy webServiceProxy() {
return new WebServiceProxy();
}
#Bean(name = "webServiceProxyBeanFactory")
public WebServiceProxyBeanFactory webServiceProxyBeanFactory() {
return new WebServiceProxyBeanFactory();
}
}
Now everything is in place. it's time to write a hook to start scanning Web service packages and register dynamic proxies as beans. I will provide implementation of ImportBeanDefinitionRegistrar.
WebServiceProxyBeansRegistrar
#Configuration
public class WebServiceProxyBeansRegistrar implements ImportBeanDefinitionRegistrar, BeanClassLoaderAware {
private ClassPathScanner classpathScanner;
private ClassLoader classLoader;
public WebServiceProxyBeansRegistrar() {
classpathScanner = new ClassPathScanner(false);
classpathScanner.addIncludeFilter(new AnnotationTypeFilter(WebService.class));
}
#Override
public void setBeanClassLoader(ClassLoader classLoader) {
this.classLoader = classLoader;
}
#Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
String[] basePackages = getBasePackages(importingClassMetadata);
if (ArrayUtils.isNotEmpty(basePackages)) {
for (String basePackage : basePackages) {
createWebServicProxies(basePackage, registry);
}
}
}
private String[] getBasePackages(AnnotationMetadata importingClassMetadata) {
String[] basePackages = null;
MultiValueMap<String, Object> allAnnotationAttributes =
importingClassMetadata.getAllAnnotationAttributes(EnableWebServices.class.getName());
if (MapUtils.isNotEmpty(allAnnotationAttributes)) {
basePackages = (String[]) allAnnotationAttributes.getFirst("basePackages");
}
return basePackages;
}
private void createWebServicProxies(String basePackage, BeanDefinitionRegistry registry) {
try {
for (BeanDefinition beanDefinition : classpathScanner.findCandidateComponents(basePackage)) {
Class<?> clazz = Class.forName(beanDefinition.getBeanClassName());
WebService webService = clazz.getAnnotation(WebService.class);
String beanName = StringUtils.isNotEmpty(webService.bean())
? webService.bean() : ClassUtils.getShortNameAsProperty(clazz);
GenericBeanDefinition proxyBeanDefinition = new GenericBeanDefinition();
proxyBeanDefinition.setBeanClass(clazz);
ConstructorArgumentValues args = new ConstructorArgumentValues();
args.addGenericArgumentValue(classLoader);
args.addGenericArgumentValue(clazz);
proxyBeanDefinition.setConstructorArgumentValues(args);
proxyBeanDefinition.setFactoryBeanName("webServiceProxyBeanFactory");
proxyBeanDefinition.setFactoryMethodName("createWebServiceProxyBean");
registry.registerBeanDefinition(beanName, proxyBeanDefinition);
}
} catch (Exception e) {
System.out.println("Exception while createing proxy");
e.printStackTrace();
}
}
}
In this class, I extracted all packages provided in EnableWebServices annotation. for each extracted package, I used ClassPathScanner to scan. (Here logic can be refined to filter only WebService annotated interfaces). For each detected interface, I have registered a bean definitions. Please note I have used webServiceProxyBeanFactory and called its createWebServiceProxyBean with classLoader and type of interface. This factory method, when invoked by spring later, will return bean of same type as that of interface, so bean with correct type is registered. This bean can be injected anywhere with interface type. Moreover, WebServiceProxy can inject and use any other bean. So autowiring will also work as expected.
Is your InvocationHandler a bean? You should create it as a bean, not just a simple object to get Autowired working
I was thinking about the same problem but in a slightly more lightweight context. I don't need to load dynamicaly all the webservice clients. So instead I used a FactoryBean and within this factory bean I constructed the dynamic proxy. Here is one example where Autowiring of the service works:
public class CurrencyServiceWithDynamicProxy extends AbstractFactoryBean<CurrencyService> {
ServiceClientConfiguration clientConfiguration;
Object proxy;
#Autowired
public CurrencySyncFactoryDynamicProxy(ServiceClientConfigurationProvider serviceClientConfigurationProvider) {
this.clientConfiguration = serviceClientConfigurationProvider.createClientConfig("currency");
proxy = Proxy.newProxyInstance(getClass().getClassLoader(), new Class<?>[] { getObjectType() }, new MyInvocationHandler());
}
#Override
public Class<CurrencySync> getObjectType() {
// TODO Auto-generated method stub
return CurrencyService.class;
}
#Override
public CurrencySync createInstance() throws Exception {
// do some creational logic
return (CurrencySync)proxy;
}
public CurrencySync createService() {
JaxWsProxyFactoryBean factory = new JaxWsProxyFactoryBean();
factory.setServiceClass(getObjectType());
factory.getFeatures().add(som features);
return getObjectType().cast(factory.create());
}
}
With respect of the accepted answer this factory example can easily be extended into a more dynamic version.