You can define your own Spring Scope. One thing to consider is that the beans that are defined in a scope must somehow be backed by a store. For the singlton scope this is the application context itself, for a session scope it is the session, for a request scope it is the request. With this setup the beans lifecycle is bound to the lifecycle of the backing store, e.g. when a session terminates it is deleted and with it all the corresponding beans.<\/p>\n
There are other examples<\/a> out there that implement a custom scope by implementing the store in the scope. This then requires that the lifecycle has to be managed from the outside. So let’s do this the right way:<\/p>\n <\/p>\n To simplify the example let’s assume that there can only be one dialog at a time. The Scope implementation follows this example<\/a> closely. The main difference is that there are two methods which define the start of the scope boundary and the end. A bean of in this scope may only be created after the start and before the end. This is necessary as the lifecycle of the Scope bean is that of a singleton and therefore the store backing the scope would have the same lifecycle. With designating the start and end the access control to the store can be limited.<\/p>\n So here is the Scope implementation:<\/p>\n <\/p>\n And the configuration in the spring context.<\/p>\n <\/p>\n Up until now this is nothing really novel. The clever bit comes now. It’s not terribly complicated but I have not seen any example that combine these two techniques to that effect: We are using Aspect Oriented Programming to control the scope. Somewhere in the application code there will be a method opening a dialog and a method closing the dialog. These are the two points we want to connect to the start and end of the scope. I have chosen to mark these methods with custom annotations. This is not really necessary as one can also use the direct method name, however there are two potential pitfalls:<\/p>\n So here are the two annotations:<\/p>\n Now the most complex part is the definition of the aspect:<\/p>\n The aspect takes nicely care of starting the scope before the dialog is opened and ending it again on closing.<\/p>\n And finally there is some configuration needed in the spring context.<\/p>\n There are some dependencies that are required here defined in the pom.xml:<\/p>\n Finally we want to see if that all worked out. We can do this with this nice little Test.<\/p>\n As the asserts show the Location bean which is defined with the dialog scope is only present after the dialog is opened before it is closed again.<\/p>\n The output of the various sysouts gives us this:<\/p>\n The annotation approach is largely inspired by this article.<\/a><\/p>\n","protected":false},"excerpt":{"rendered":" You can define your own Spring Scope. One thing to consider is that the beans that are defined in a scope must somehow be backed by a store. For the singlton scope this is the application context itself, for a session scope it is the session, for a request scope it is the request. With … \u201eCustom Spring scope done right\u201c <\/span>weiterlesen<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[291,290,269],"class_list":["post-2382","post","type-post","status-publish","format-standard","hentry","category-java","tag-aspect","tag-scope","tag-spring"],"_links":{"self":[{"href":"http:\/\/sahits.ch\/blog\/wp-json\/wp\/v2\/posts\/2382","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/sahits.ch\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/sahits.ch\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/sahits.ch\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/sahits.ch\/blog\/wp-json\/wp\/v2\/comments?post=2382"}],"version-history":[{"count":3,"href":"http:\/\/sahits.ch\/blog\/wp-json\/wp\/v2\/posts\/2382\/revisions"}],"predecessor-version":[{"id":2385,"href":"http:\/\/sahits.ch\/blog\/wp-json\/wp\/v2\/posts\/2382\/revisions\/2385"}],"wp:attachment":[{"href":"http:\/\/sahits.ch\/blog\/wp-json\/wp\/v2\/media?parent=2382"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/sahits.ch\/blog\/wp-json\/wp\/v2\/categories?post=2382"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/sahits.ch\/blog\/wp-json\/wp\/v2\/tags?post=2382"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}\n
public class DialogScope implements Scope {\r\n private Map<String, Object> objectMap = Collections.synchronizedMap(new HashMap<String, Object>());\r\n private volatile boolean scopeOpen = false;\r\n\r\n public DialogScope() {\r\n System.out.println(getClass().getName()+\": Creating scope\");\r\n }\r\n\r\n \/**\r\n * Mark the begining of the scope, before the scope is opened no beans are registered.\r\n *\/\r\n public void openScope() {\r\n scopeOpen = true;\r\n System.out.println(getClass().getName()+\": Opened the scope\");\r\n }\r\n\r\n \/**\r\n * Mark the end of the scope, after the scope is closed, no beans are registered.\r\n *\/\r\n public void closeScope() {\r\n scopeOpen = false;\r\n clear();\r\n System.out.println(getClass().getName()+\": Closed the scope\");\r\n }\r\n\r\n @Override\r\n public Object get(String name, ObjectFactory<?> objectFactory) {\r\n if (scopeOpen && !objectMap.containsKey(name)) {\r\n \/\/ Only add the bean if the scope is open and the bean is not yet already registered\r\n objectMap.put(name, objectFactory.getObject());\r\n }\r\n return objectMap.get(name);\r\n }\r\n\r\n @Override\r\n public Object remove(String name) {\r\n return objectMap.remove(name);\r\n }\r\n\r\n @Override\r\n public void registerDestructionCallback(String name, Runnable callback) {\r\n \/\/ do nothing\r\n }\r\n\r\n @Override\r\n public Object resolveContextualObject(String key) {\r\n return null;\r\n }\r\n\r\n \/**\r\n * Clear the cached beans in the scopes backing store\r\n *\/\r\n private void clear() {\r\n objectMap.clear();\r\n System.out.println(getClass().getName()+\": Clear scope\");\r\n }\r\n\r\n @Override\r\n public String getConversationId() {\r\n return \"Dialog\";\r\n }\r\n}<\/pre>\n <bean id=\"dialogScope\" class=\"ch.sahits.spring.DialogScope\" \/>\r\n\r\n <bean class=\"org.springframework.beans.factory.config.CustomScopeConfigurer\">\r\n <property name=\"scopes\">\r\n <map>\r\n <entry key=\"dialog\">\r\n <ref bean=\"dialogScope\" \/>\r\n <\/entry>\r\n <\/map>\r\n <\/property>\r\n <\/bean><\/pre>\n
\n
@Retention(RetentionPolicy.RUNTIME)\r\n@Target(ElementType.METHOD)\r\npublic @interface DialogOpening {\r\n}\r\n\r\n@Retention(RetentionPolicy.RUNTIME)\r\n@Target(ElementType.METHOD)\r\npublic @interface DialogCloseing {\r\n}<\/pre>\n@Aspect\r\npublic class DialogAspect {\r\n @Autowired\r\n private DialogScope scope;\r\n\r\n @Pointcut(value=\"execution(public * *(..))*\")\r\n public void anyPublicMethod() {\r\n }\r\n @Before(\"anyPublicMethod() && @annotation(dialogOpening)\")\r\n public void openDialog(JoinPoint pjp, DialogOpening dialogOpening) throws Throwable {\r\n System.out.println(getClass().getName()+\": In opening aspect:\");\r\n for (java.lang.Object o : pjp.getArgs()) {\r\n System.out.println(o);\r\n }\r\n scope.openScope();\r\n }\r\n @After(\"anyPublicMethod() && @annotation(dialogCloseing)\")\r\n public void openDialog(JoinPoint pjp, DialogCloseing dialogCloseing) throws Throwable {\r\n System.out.println(getClass().getName()+\": In closing aspect:\");\r\n for (java.lang.Object o : pjp.getArgs()) {\r\n System.out.println(o);\r\n }\r\n scope.closeScope();\r\n }\r\n}<\/pre>\n<aop:aspectj-autoproxy \/>\r\n\r\n<bean id=\"DialogScopeAspect\" class=\"ch.sahits.spring.aop.DialogAspect\" \/><\/pre>\n
<dependency>\r\n <groupId>org.springframework<\/groupId>\r\n <artifactId>spring<\/artifactId>\r\n <version>3.2.0.RELEASE<\/version>\r\n<\/dependency>\r\n<dependency>\r\n <groupId>org.springframework<\/groupId>\r\n <artifactId>spring-beans<\/artifactId>\r\n <version>3.2.0.RELEASE<\/version>\r\n<\/dependency>\r\n<dependency>\r\n <groupId>org.springframework<\/groupId>\r\n <artifactId>spring-core<\/artifactId>\r\n <version>3.2.0.RELEASE<\/version>\r\n<\/dependency>\r\n<dependency>\r\n <groupId>org.springframework<\/groupId>\r\n <artifactId>spring-context<\/artifactId>\r\n <version>3.2.0.RELEASE<\/version>\r\n<\/dependency>\r\n<dependency>\r\n <groupId>org.springframework<\/groupId>\r\n <artifactId>spring-aop<\/artifactId>\r\n <version>3.2.0.RELEASE<\/version>\r\n<\/dependency>\r\n<dependency>\r\n <groupId>org.aspectj<\/groupId>\r\n <artifactId>aspectjrt<\/artifactId>\r\n <version>1.6.11<\/version>\r\n<\/dependency>\r\n\r\n<dependency>\r\n <groupId>org.aspectj<\/groupId>\r\n <artifactId>aspectjweaver<\/artifactId>\r\n <version>1.6.11<\/version>\r\n<\/dependency> <dependency>\r\n <groupId>javax.xml.bind<\/groupId>\r\n <artifactId>jaxb-api<\/artifactId>\r\n <version>2.1<\/version>\r\n<\/dependency>\r\n<dependency>\r\n <groupId>com.sun.xml.bind<\/groupId>\r\n <artifactId>jaxb-impl<\/artifactId>\r\n <version>2.1.13<\/version>\r\n<\/dependency>\r\n<dependency>\r\n <groupId>org.springframework<\/groupId>\r\n <artifactId>spring-oxm<\/artifactId>\r\n <version>3.2.0.RELEASE<\/version>\r\n<\/dependency>\r\n<dependency>\r\n <groupId>org.springframework<\/groupId>\r\n <artifactId>spring-test<\/artifactId>\r\n <version>3.2.0.RELEASE<\/version>\r\n<\/dependency>\r\n<dependency>\r\n <groupId>junit<\/groupId>\r\n <artifactId>junit<\/artifactId>\r\n <version>4.11<\/version>\r\n<\/dependency><\/pre>\n
@Test\r\npublic void testScope() {\r\n\tClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(\"spring-context.xml\");\r\n\tWindowOpening instance = context.getBean(WindowOpening.class);\r\n\r\n\tassertNull(\"Dialog scoped bean Location may not be available before scope is started\", context.getBean(Location.class));\r\n\tinstance.openDialog(\"GenericDialog\");\r\n\tassertNotNull(\"Dialog scoped bean Location must be available after scope is started\", context.getBean(Location.class));\r\n\tThread.currentThread();\r\n\ttry {\r\n\t Thread.sleep(5000);\r\n\t} catch (InterruptedException e) {\r\n\t e.printStackTrace();\r\n\t}\r\n\tinstance.closeDialog(\"GenericDialog\");\r\n\tassertNull(\"Dialog scoped bean Location may not be available after scope is closed\", context.getBean(Location.class));\r\n}<\/pre>\nch.sahits.spring.DialogScope: Creating scope\r\nch.sahits.spring.aop.DialogAspect: In opening aspect:\r\nGenericDialog\r\nch.sahits.spring.DialogScope: Opened the scope\r\nch.sahits.spring.WindowOpening: Opened a dialog: GenericDialog\r\nCreating the location\r\nch.sahits.spring.WindowOpening: Close a dialog: GenericDialog\r\nch.sahits.spring.aop.DialogAspect: In closing aspect:\r\nGenericDialog\r\nch.sahits.spring.DialogScope: Clear scope\r\nch.sahits.spring.DialogScope: Closed the scope<\/pre>\n