Merge pull request #41 from eileenmcnaughton/master

#261 clarify meaning of transactionRef and add transactionId as a sta…

src/Omnipay/Common/Message/AbstractRequest.php

@@ -455,6 +455,8 @@ public function setDescription($value)
     /**
      * Get the transaction ID.
      *
+     * The transaction ID is the identifier generated by the merchant website.
+     *
      * @return string
      */
     public function getTransactionId()
@@ -476,6 +478,9 @@ public function setTransactionId($value)
     /**
      * Get the transaction reference.
      *
+     * The transaction reference is the identifier generated by the remote
+     * payment gateway.
+     *
      * @return string
      */
     public function getTransactionReference()

src/Omnipay/Common/Message/AbstractResponse.php

@@ -37,7 +37,7 @@ abstract class AbstractResponse implements ResponseInterface
      * @var RequestInterface
      */
     protected $request;
-    
+
     /**
      * The data contained in the response.
      *
@@ -147,6 +147,16 @@ public function getTransactionReference()
         return null;
     }
 
+    /**
+     * Get the transaction ID as generated by the merchant website.
+     *
+     * @return string
+     */
+    public function getTransactionId()
+    {
+        return null;
+    }
+
     /**
      * Automatically perform any required redirect
      *