Add mechanism to return server protocol serial version

Author: gmfeinberg

driver/src/main/java/oracle/nosql/driver/http/Client.java

@@ -25,6 +25,7 @@
 import static oracle.nosql.driver.util.HttpConstants.REQUEST_NAMESPACE_HEADER;
 import static oracle.nosql.driver.util.HttpConstants.NOSQL_DATA_PATH;
 import static oracle.nosql.driver.util.HttpConstants.REQUEST_ID_HEADER;
+import static oracle.nosql.driver.util.HttpConstants.SERVER_SERIAL_VERSION;
 import static oracle.nosql.driver.util.HttpConstants.USER_AGENT;
 import static oracle.nosql.driver.util.HttpConstants.X_RATELIMIT_DELAY;
 import static oracle.nosql.driver.util.LogUtil.isLoggable;
@@ -1230,10 +1231,20 @@ final Result processResponse(HttpResponseStatus status,
 
         setSessionCookie(headers);
 
+        Result res = null;
         try (ByteInputStream bis = new NettyByteInputStream(content)) {
-            return processOKResponse(bis, kvRequest, serialVersionUsed,
-                                     queryVersionUsed);
+            res = processOKResponse(bis, kvRequest, serialVersionUsed,
+                                    queryVersionUsed);
         }
+        String sv = headers.get(SERVER_SERIAL_VERSION);
+        if (sv != null) {
+            try {
+                res.setServerSerialVersion(Integer.parseInt(sv));
+            } catch (Exception e) {
+                /* ignore */
+            }
+        }
+        return res;
     }
 
     /**

driver/src/main/java/oracle/nosql/driver/ops/Result.java

@@ -22,6 +22,13 @@ public class Result {
     private int readUnits;
     private int writeKB;
 
+    /*
+     * if available, the serial version of the proxy, otherwise 0. This
+     * allows the SDK to conditionalize code and tests based on new features
+     * and semantics
+     */
+    private int serialVersion;
+
     /*
      * Cloud Only
      * If rate limiting is in place, this value will represent the number of
@@ -163,4 +170,23 @@ public TopologyInfo getTopology() {
     public void setTopology(TopologyInfo ti) {
         topology = ti;
     }
+
+    /**
+     * @hidden
+     * Returns the server protocol serial version or 0 if not available.
+     * This is a new feature not supported in older servers.
+     *
+     * @return the serial version of the server
+     */
+    public int getServerSerialVersion() {
+        return serialVersion;
+    }
+
+    /**
+     * @hidden
+     * @param version the server's serial version
+     */
+    public void setServerSerialVersion(int version) {
+        serialVersion = version;
+    }
 }

driver/src/main/java/oracle/nosql/driver/util/HttpConstants.java

@@ -52,6 +52,17 @@ public class HttpConstants {
      */
     public static final String REQUEST_NAMESPACE_HEADER = "x-nosql-default-ns";
 
+    /**
+     * A header that indicates the serial version of the protocol used by the
+     * server (proxy).
+     */
+    public static final String SERVER_SERIAL_VERSION = "x-nosql-serial-version";
+
+    /**
+     * A header that indicates the version of the proxy and kv used.
+     */
+    public static final String SERVER_VERSION = "x-nosql-version";
+
     /**
      * Headers possibly set by the load balancer service to indicate original
      * IP address