I’m a heavy user of generalized classes and interfaces in Java.Sadly, the generalization is only for compile-time checks. But because you can cast any parameterized class-instance to an unchecked instance you can fool the system. This can be very annoying if a class-cast exception occurs later. For example with collections, the ClassCastException happens somewhere later and the stacktrace points to the wrong location.<\/p>\n
Well for Collections there is a simple solution available. You can create runtime-checked Collections with the Collections-class<\/p>\n
List<String> test = Collections.checkedList(new ArrayList<String>(),String.class); The bad thing is, this is made just for collections. Now I’m thinking about creating an small library, which can create runtime-checks for any interface. Since I saw the little trick on the Google-Guice-library, this seems to be solvable. Sure, you have to use some dirty tricks to archive this goal, but maybe it is realizable.<\/p>\n The following code-snippet shows, what I’m thinking of:<\/p>\n \/\/ This is our target-type \/\/ To create in the code, we create an inner-class of the Type-interface. <\/em><\/p>\n <\/em><\/p>\n<\/p>\n And the code for more dynamic creation, for example when you create a typed based on configuration:<\/p>\n \/\/ There has to be a possibility to create the same type complete dynamically. \/\/ Build the first parameter The Type.ANY_TYPE represents the ? on the parameterlist. \/\/ Create the second parameter \/\/ Create the final type \/\/ Ugly cast =( I’m a heavy user of generalized classes and interfaces in Java.Sadly, the generalization is only for compile-time checks. But because you can cast any parameterized class-instance to an unchecked instance… <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_links_to":"","_links_to_target":""},"categories":[15],"tags":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.gamlor.info\/wordpress\/wp-json\/wp\/v2\/posts\/55"}],"collection":[{"href":"https:\/\/www.gamlor.info\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.gamlor.info\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.gamlor.info\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.gamlor.info\/wordpress\/wp-json\/wp\/v2\/comments?post=55"}],"version-history":[{"count":1,"href":"https:\/\/www.gamlor.info\/wordpress\/wp-json\/wp\/v2\/posts\/55\/revisions"}],"predecessor-version":[{"id":3768,"href":"https:\/\/www.gamlor.info\/wordpress\/wp-json\/wp\/v2\/posts\/55\/revisions\/3768"}],"wp:attachment":[{"href":"https:\/\/www.gamlor.info\/wordpress\/wp-json\/wp\/v2\/media?parent=55"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.gamlor.info\/wordpress\/wp-json\/wp\/v2\/categories?post=55"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.gamlor.info\/wordpress\/wp-json\/wp\/v2\/tags?post=55"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
List somewhereElse = test;
somewhereElse.add(44); \/\/ Here the ClassCastException will be thrown<\/em><\/p>\n
Task<Map<String, ?>, List<? extends InputStream>> targetType; <\/em><\/p>\n<\/p>\n
\/\/ This type will be interpreted by the system to create the typed version.
\/\/ Then we bind it the the normal implementation class and create an instance at the end.
targetType =
RuntimeTypeSave.create(new Type<Task<Map<String, ?>, List<? extends InputStream>>>() {})
.bindTo(new HashMap())
.createInstance(); <\/em><\/p>\n
\/\/ Because the type may get constructet depending on a configuration. <\/em><\/p>\n<\/p>\n
Builder<Map> firstParam = RuntimeTypeSave.getBuilder(Map.class);
Type firstType = firstParam.setParameters(String.class, Type.ANY_TYPE.class).createType(); <\/em><\/p>\n
Builder<List> secondParam = RuntimeTypeSave.getBuilder(List.class);
Type secondType = secondParam.extendsFrom(InputStream.class).createType(); <\/em><\/p>\n
Type<Task> finalType = RuntimeTypeSave
.getBuilder(Task.class).setParameters(firstType, secondType)
.createType(); <\/em><\/p>\n
targetType = (Task<Map<String,?>, List<? extends InputStream>>) RuntimeTypeSave.create(finalType).
bindTo(new TaskImpl()).createInstance();<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"