如果一个类定义了一个注释,是否有可能迫使其子类定义相同的注释?
例如,我们有一个简单的类/子类对,它们共享@Author @interface. 我想做的事情,就是迫使每个进一步的子类定义相同的@Author注释,以防止RuntimeException将来出现问题。
@Author @interface.
@Author
RuntimeException
TestClass.java:
import java.lang.annotation.*; @Retention(RetentionPolicy.RUNTIME) @interface Author { String name(); } @Author( name = "foo" ) public abstract class TestClass { public static String getInfo( Class<? extends TestClass> c ) { return c.getAnnotation( Author.class ).name(); } public static void main( String[] args ) { System.out.println( "The test class was written by " + getInfo( TestClass.class ) ); System.out.println( "The test subclass was written by " + getInfo( TestSubClass.class ) ); } }
TestSubClass.java:
@Author( name = "bar" ) public abstract class TestSubClass extends TestClass {}
我知道我可以在运行时枚举所有批注并检查是否丢失了@Author,但是我真的很想在编译时执行此操作(如果可能)。
您可以在编译时使用JSR 269进行此操作。参见:http : //today.java.net/pub/a/today/2006/06/29/validate-java-ee- annotations-with-annotation-processors.html#pluggable-annotation-processing- api