From db6c09038794d57a7879189096abc7991e2502c8 Mon Sep 17 00:00:00 2001
From: Jonathan Mace <jonathan.c.mace@gmail.com>
Date: Wed, 10 May 2017 12:35:09 -0400
Subject: [PATCH] Add 'isValid' method

---
 .../src/main/java/brown/tracingplane/BaggageProvider.java   | 6 ++++++
 .../noopprovider/NoOpBaggageContextProvider.java            | 5 +++++
 2 files changed, 11 insertions(+)

diff --git a/baggagecontext/api/src/main/java/brown/tracingplane/BaggageProvider.java b/baggagecontext/api/src/main/java/brown/tracingplane/BaggageProvider.java
index 4620da0..844ade5 100644
--- a/baggagecontext/api/src/main/java/brown/tracingplane/BaggageProvider.java
+++ b/baggagecontext/api/src/main/java/brown/tracingplane/BaggageProvider.java
@@ -10,6 +10,12 @@ import java.nio.ByteBuffer;
  */
 public interface BaggageProvider<B extends BaggageContext> {
 
+    /**
+     * @param baggage a BaggageContext to test
+     * @return true if <code>baggage</code> is an instance of {@link B} or if baggage is null.
+     */
+    boolean isValid(BaggageContext baggage);
+
     /**
      * @return a new instance of {@link B}, which may be null to indicate an empty baggage
      */
diff --git a/baggagecontext/noop-impl/src/main/java/brown/tracingplane/noopprovider/NoOpBaggageContextProvider.java b/baggagecontext/noop-impl/src/main/java/brown/tracingplane/noopprovider/NoOpBaggageContextProvider.java
index 9099b0d..bef49ca 100644
--- a/baggagecontext/noop-impl/src/main/java/brown/tracingplane/noopprovider/NoOpBaggageContextProvider.java
+++ b/baggagecontext/noop-impl/src/main/java/brown/tracingplane/noopprovider/NoOpBaggageContextProvider.java
@@ -9,6 +9,11 @@ import brown.tracingplane.BaggageProvider;
  */
 public class NoOpBaggageContextProvider implements BaggageProvider<BaggageContext> {
 
+    @Override
+    public boolean isValid(BaggageContext baggage) {
+        return baggage == null;
+    }
+
     @Override
     public BaggageContext newInstance() {
         return null;
-- 
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