import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.SOURCE)
public @interface MyAnnotation {
String value();
}
import javax.annotation.processing.AbstractProcessor;
import javax.annotation.processing.ProcessingEnvironment;
import javax.annotation.processing.RoundEnvironment;
import javax.annotation.processing.SupportedAnnotationTypes;
import javax.annotation.processing.SupportedSourceVersion;
import javax.lang.model.SourceVersion;
import javax.lang.model.element.TypeElement;
import java.io.IOException;
import java.io.Writer;
import java.util.Set;
@SupportedAnnotationTypes("com.example.MyAnnotation")
@SupportedSourceVersion(SourceVersion.RELEASE_8)
public class MyAnnotationProcessor extends AbstractProcessor {
@Override
public synchronized void init(ProcessingEnvironment processingEnv) {
super.init(processingEnv);
}
@Override
public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
for (TypeElement annotation : annotations) {
Set<? extends Element> annotatedElements = roundEnv.getElementsAnnotatedWith(annotation);
for (Element element : annotatedElements) {
MyAnnotation myAnnotation = element.getAnnotation(MyAnnotation.class);
String value = myAnnotation.value();
String newSourceCode = generateNewSourceCode(value);
try (Writer writer = processingEnv.getFiler().createSourceFile("GeneratedClass").openWriter()) {
writer.write(newSourceCode);
} catch (IOException e) {
e.printStackTrace();
}
}
}
return true;
}
private String generateNewSourceCode(String value) {
// ...
}
}
com.example.MyAnnotationProcessor
