1 files changed, 27 insertions, 0 deletions
diff --git a/sampleUses/src/main/java/CreditCardNumber.java b/sampleUses/src/main/java/CreditCardNumber.java
new file mode 100644
index 0000000..ef5f711
--- /dev/null
+++ b/sampleUses/src/main/java/CreditCardNumber.java
@@ -0,0 +1,27 @@
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+import javax.annotation.MatchesPattern;
+import javax.annotation.meta.TypeQualifier;
+import javax.annotation.meta.TypeQualifierValidator;
+import javax.annotation.meta.When;
+
+@Documented
+@TypeQualifier
+@MatchesPattern("[0-9]{16}")
+@Retention(RetentionPolicy.RUNTIME)
+public @interface CreditCardNumber {
+	class Checker implements TypeQualifierValidator<CreditCardNumber> {
+
+		public When forConstantValue(CreditCardNumber annotation, Object v) {
+			if (!(v instanceof String))
+				return When.NEVER;
+			String s = (String) v;
+			if (LuhnVerification.checkNumber(s))
+				return When.ALWAYS;
+			return When.NEVER;
+		}
+	}
+}