Update #0 - First Release

sources/main/java/javax/annotation/Nonnegative.java

@@ -0,0 +1,47 @@
+package javax.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+import javax.annotation.meta.TypeQualifier;
+import javax.annotation.meta.TypeQualifierValidator;
+import javax.annotation.meta.When;
+
+/**
+ * This annotation is used to annotate a value that should only contain
+ * nonnegative values.
+ * <p>
+ * When this annotation is applied to a method it applies to the method return
+ * value.
+ */
+@Documented
+@TypeQualifier(applicableTo = Number.class)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface Nonnegative {
+	When when() default When.ALWAYS;
+
+	class Checker implements TypeQualifierValidator<Nonnegative> {
+
+		public When forConstantValue(Nonnegative annotation, Object v) {
+			if (!(v instanceof Number))
+				return When.NEVER;
+			boolean isNegative;
+			Number value = (Number) v;
+			if (value instanceof Long)
+				isNegative = value.longValue() < 0;
+			else if (value instanceof Double)
+				isNegative = value.doubleValue() < 0;
+			else if (value instanceof Float)
+				isNegative = value.floatValue() < 0;
+			else
+				isNegative = value.intValue() < 0;
+
+			if (isNegative)
+				return When.NEVER;
+			else
+				return When.ALWAYS;
+
+		}
+	}
+}