- Added a "KafkaVersion" annotation type so Vino can start adding version constraints to his code.
diff --git a/connectors/kafka/src/main/java/org/apache/edgent/connectors/kafka/annotations/KafkaVersion.java b/connectors/kafka/src/main/java/org/apache/edgent/connectors/kafka/annotations/KafkaVersion.java
new file mode 100644
index 0000000..f33bc09
--- /dev/null
+++ b/connectors/kafka/src/main/java/org/apache/edgent/connectors/kafka/annotations/KafkaVersion.java
@@ -0,0 +1,28 @@
+package org.apache.edgent.connectors.kafka.annotations;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * In order to prevent the need to implement multiple versions of kafka-adapters.
+ * The {@link KafkaVersion} annotation allows specifying a minimum and maximum version
+ * of Kafka that supports a given functionality. This information currently can only
+ * be provided on a class/type (includes all methods) or individual method level.
+ *
+ * This information is then used by an aspect that wraps access to version constrained
+ * methods and throws meaningful exceptions when being used without satisfying the
+ * version criteria.
+ */
+// We need the information to be available at runtime.
+@Retention(RetentionPolicy.RUNTIME)
+// We will only annotate methods or classes with this version check.
+@Target({ElementType.METHOD, ElementType.TYPE})
+public @interface KafkaVersion {
+
+ String fromVersion();
+
+ String toVersion();
+
+}
