package com.yiibai.tutorial.ann4;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Retention(RetentionPolicy.RUNTIME)
// Using for Class, interface, annotation, enum.
@Target(value = { ElementType.TYPE})
// Simulating the <UL> in HTML.
public @interface AnnHtmlUL {
public String border() default "border:1px solid blue;";

}

• AnnHtmlLI.java

package com.yiibai.tutorial.ann4;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Retention(RetentionPolicy.RUNTIME)
@Target(value = { ElementType.FIELD,ElementType.METHOD})
// Simulating the <LI> in HTML.
public @interface AnnHtmlLI {
public String background();

public String color() default "red";

}

• DocumentClass.java

package com.yiibai.tutorial.ann4;
@AnnHtmlUL(border = "1px solid red")
public class DocumentClass {
private String author;

@AnnHtmlLI(background = "blue", color = "black")
public String getDocumentName() {
    return "Java Core";
}

@AnnHtmlLI(background = "yellow")
public String getDocumentVersion() {
    return "1.0";
}

@AnnHtmlLI(background = "green")
public void setAuthor(String author) {
    this.author = author;
}

@AnnHtmlLI(background = "red", color = "black")
public String getAuthor() {
    return author;
}

// This method is not annotated
public float getPrice()  {
    return 100;
}

}

• HtmlGenerator.java

package com.yiibai.tutorial.ann4;
import java.lang.reflect.Method;
public class HtmlGenerator {
public static void main(String[] args) {

    Class<?> clazz = DocumentClass.class;

     // Check if this class is annotated by Annotation AnnHtmlUL or not.
    boolean isHtmlUL = clazz.isAnnotationPresent(AnnHtmlUL.class);

    StringBuilder sb = new StringBuilder();
    if (isHtmlUL) {
        // Get the AnnHtmlUL annotation on this class.
        AnnHtmlUL annUL = clazz.getAnnotation(AnnHtmlUL.class);

        sb.append("<H3>" + clazz.getName() + "</H3>");
        sb.append("\n");


        // Get the value of the element 'border'.
        String border = annUL.border();

        sb.append("<UL style='border:" + border + "'>");
        
        // Add new line
        sb.append("\n");

        Method[] methods = clazz.getMethods();

        for (Method method : methods) {
            // Check if this method is annotated by Annotation AnnHtmlLI or not.
            if (method.isAnnotationPresent(AnnHtmlLI.class)) {

                // Get the annotation
                AnnHtmlLI annLI = method.getAnnotation(AnnHtmlLI.class);

                // Get the values of elements.
                String background = annLI.background();
                String color = annLI.color();

                sb.append("<LI style='margin:5px;padding:5px;background:"
                        + background + ";color:" + color + "'>");
                sb.append("\n");
                sb.append(method.getName());
                sb.append("\n");
                sb.append("</LI>");
                sb.append("\n");
            }
        }
        sb.append("</UL>");
    }
    writeToFile(clazz.getSimpleName() + ".html", sb);
}

// Write to Console (Or file)
private static void writeToFile(String fileName, StringBuilder sb) {
    System.out.println(sb);
}

}