Under the Hood: Using Spring in Grails
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The document provides an overview of using Spring in Grails, detailing the main functions of Spring such as dependency injection, transaction management, and bean post-processing. It explains concepts like aliases, Spring MVC controllers, and transaction utility methods with code examples. The document also highlights various programming techniques for defining and managing beans in a Grails application.
![Alternate approach to BeanDefinition modification
def doWithSpring = {
def mybeanDef = delegate.getBeanDefinition('mybean')
mybeanDef.beanClass = NewClass
mybeanDef.propertyValues.add("order",
application.config.plugin?.rendering?.order ?: 42)
}
● Use loadAfter = ['plugin1', 'plugin2'] to
ensure the bean is loaded
● Only valid in a plugin, not the app's resources.groovy
CONFIDENTIAL 10](https://image.slidesharecdn.com/spring-120608093532-phpapp01/85/Under-the-Hood-Using-Spring-in-Grails-10-320.jpg)
![Spring MVC
New in Grails 1.2
Annotate src/java or src/groovy classes with @Controller
Add all packages to the grails.spring.bean.packages list in
Config.groovy
• e.g.grails.spring.bean.packages = ['gr8conf.testapp.foo']
CONFIDENTIAL 15](https://image.slidesharecdn.com/spring-120608093532-phpapp01/85/Under-the-Hood-Using-Spring-in-Grails-15-320.jpg)
![A Simple Proxied Bean – The FactoryBean
public void setTarget(ThingManager manager) {
target = manager;
}
public void afterPropertiesSet() {
Assert.notNull(target,
"The proxied manager must be set");
Class<?>[] interfaces = { ThingManager.class };
InvocationHandler invocationHandler =
new InvocationHandler() {
public Object invoke(Object proxy,
Method m, Object[] args)
throws Throwable {
CONFIDENTIAL 29](https://image.slidesharecdn.com/spring-120608093532-phpapp01/85/Under-the-Hood-Using-Spring-in-Grails-29-320.jpg)
Under the Hood: Using Spring in Grails
- 1. Under the Hood: Using Spring in Grails Burt Beckwith SpringSource
- 3. Who Am I Java developer for over 13 years Background in Spring, Hibernate, Spring Security Grails developer for 5 years SpringSource employee on the Grails team Created or reworked over 40 Grails plugins http://burtbeckwith.com/blog/ https://twitter.com/#!/burtbeckwith CONFIDENTIAL 3
- 4. Spring Overview Main functions of Spring • Bean container: ApplicationContext and BeanFactory • Dependency Injection (DI) and Inversion of Control (IoC) • Proxies • Transactions • Security • Caching • Event publishing and listening • Exception conversion CONFIDENTIAL 4
- 5. Bean PostProcessors CONFIDENTIAL 5
- 6. Bean PostProcessors o.s.b.factory.config.BeanPostProcessor • Object postProcessBeforeInitialization(Object bean, String beanName) • Object postProcessAfterInitialization(Object bean, String beanName) CONFIDENTIAL 6
- 7. Bean PostProcessors o.s.b.factory.config.BeanFactoryPostProcessor • void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) CONFIDENTIAL 7
- 8. Bean PostProcessors o.s.b.factory.support.BeanDefinitionRegistryPostProcessor • extends BeanFactoryPostProcessor • void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) CONFIDENTIAL 8
- 9. Cloud Support Plugin (cloudfoundry, heroku) dataSourceBean.driverClassName = updatedValues.driverClassName dataSourceBean.url = updatedValues.url + suffix dataSourceBean.username = updatedValues.userName dataSourceBean.password = updatedValues.password CONFIDENTIAL 9
- 10. Alternate approach to BeanDefinition modification def doWithSpring = { def mybeanDef = delegate.getBeanDefinition('mybean') mybeanDef.beanClass = NewClass mybeanDef.propertyValues.add("order", application.config.plugin?.rendering?.order ?: 42) } ● Use loadAfter = ['plugin1', 'plugin2'] to ensure the bean is loaded ● Only valid in a plugin, not the app's resources.groovy CONFIDENTIAL 10
- 11. Bean Aliases CONFIDENTIAL 11
- 12. Aliases As of Grails 2.1 aliases work fully • You can create aliases pre2.1 but only if defined in the same resources.groovy or plugin (doWithSpring) beans = { springConfig.addAlias 'alias', 'realBean' } CONFIDENTIAL 12
- 13. Aliases The cache plugin registers the alias cacheOperationSource for the bean registered as org.springframework.cache.annotation.AnnotationCacheOperationSource#0 Can use to have multiple implementations of a bean and choose one via configuration at startup, e.g. perenvironment or some other rule CONFIDENTIAL 13
- 14. Spring MVC Controllers CONFIDENTIAL 14
- 15. Spring MVC New in Grails 1.2 Annotate src/java or src/groovy classes with @Controller Add all packages to the grails.spring.bean.packages list in Config.groovy • e.g.grails.spring.bean.packages = ['gr8conf.testapp.foo'] CONFIDENTIAL 15
- 16. Spring MVC Annotate methods with @o.s.w.bind.annotation.RequestMapping @RequestMapping("/mvc/hello.dispatch") public ModelMap handleRequest() { return new ModelMap() .addAttribute("text", "some text") .addAttribute("cost", 42) .addAttribute("config", grailsApplication.getConfig().flatten())); } CONFIDENTIAL 16
- 17. Spring MVC @RequestMapping URI value must end in .dispatch Add entries in UrlMappings to create more natural URLs class UrlMappings { static mappings = { … "/mvc/hello"(uri:"/mvc/hello.dispatch") "/mvc/other"(uri:"/mvc/other.dispatch") } } CONFIDENTIAL 17
- 18. Spring MVC Use @Autowired for dependency injection (on fields in Groovy classes, on setters or constructors in Java) private GrailsApplication grailsApplication; @Autowired public void setGrailsApplication(GrailsApplication app) { grailsApplication = app; } CONFIDENTIAL 18
- 19. Transactions CONFIDENTIAL 19
- 20. Utility Methods import o.s.t.interceptor.TransactionAspectSupport import o.s.t.support.TransactionSynchronizationManager for (sc in grailsApplication.serviceClasses) { def metaClass = sc.clazz.metaClass … } CONFIDENTIAL 20
- 21. Utility Methods // returns TransactionStatus metaClass.getCurrentTransactionStatus = { > if (!delegate.isTransactionActive()) { return null } TransactionAspectSupport.currentTransactionStatus() } CONFIDENTIAL 21
- 22. Utility Methods // void, throws NoTransactionException metaClass.setRollbackOnly = { > TransactionAspectSupport.currentTransactionStatus() .setRollbackOnly() } CONFIDENTIAL 22
- 23. Utility Methods // returns boolean metaClass.isRollbackOnly = { > if (!delegate.isTransactionActive()) { return false } delegate.getCurrentTransactionStatus().isRollbackOnly() } CONFIDENTIAL 23
- 24. Utility Methods // returns boolean metaClass.isTransactionActive = { > TransactionSynchronizationManager .isSynchronizationActive() } CONFIDENTIAL 24
- 25. Proxies CONFIDENTIAL 25
- 26. A Simple Proxied Bean – The interface package gr8conf.eu.spring; public interface ThingManager { void method1(); int methodTwo(boolean foo); } CONFIDENTIAL 26
- 27. A Simple Proxied Bean – The implementation package gr8conf.eu.spring; public class ThingManagerImpl implements ThingManager { public void method1() { System.out.println("You called method1"); } public int methodTwo(boolean foo) { System.out.println("You called methodTwo"); return 42; } } CONFIDENTIAL 27
- 28. A Simple Proxied Bean – The FactoryBean package gr8conf.eu.spring; public class ThingManagerProxyFactoryBean implements FactoryBean<ThingManager>, InitializingBean { private ThingManager managerProxy; private ThingManager target; public ThingManager getObject() { return managerProxy; } public Class<ThingManager> getObjectType() { return ThingManager.class; } public boolean isSingleton() { return true; } CONFIDENTIAL 28
- 29. A Simple Proxied Bean – The FactoryBean public void setTarget(ThingManager manager) { target = manager; } public void afterPropertiesSet() { Assert.notNull(target, "The proxied manager must be set"); Class<?>[] interfaces = { ThingManager.class }; InvocationHandler invocationHandler = new InvocationHandler() { public Object invoke(Object proxy, Method m, Object[] args) throws Throwable { CONFIDENTIAL 29
- 30. A Simple Proxied Bean – The FactoryBean System.out.println("Before invoke " + m.getName()); Object value = m.invoke(target, args); System.out.println("After invoke " + m.getName()); return value; } }; managerProxy = (ThingManager)Proxy.newProxyInstance( ThingManager.class.getClassLoader(), interfaces, invocationHandler); } } CONFIDENTIAL 30
- 31. A Simple Proxied Bean – resources.groovy import gr8conf.eu.spring.ThingManager import gr8conf.eu.spring.ThingManagerImpl import gr8conf.eu.spring.ThingManagerProxyFactoryBean beans = { realThingManager(ThingManagerImpl) { // properties, etc. } thingManager(ThingManagerProxyFactoryBean) { bean > // bean.scope = ... // bean.lazyInit = true // target = ref('realThingManager') } } CONFIDENTIAL 31
- 32. A Simple Proxied Bean – resources.groovy import gr8conf.eu.spring.ThingManager import gr8conf.eu.spring.ThingManagerImpl import gr8conf.eu.spring.ThingManagerProxyFactoryBean beans = { thingManager(ThingManagerProxyFactoryBean) { bean > // bean.scope = ... // bean.lazyInit = true target = { ThingManagerImpl thing > // properties, etc. } } } CONFIDENTIAL 32
- 33. Want More Information? CONFIDENTIAL 33
- 35. Thank You CONFIDENTIAL 35