2 files changed, 47 insertions, 36 deletions

diff --git a/qpid/cpp/include/qpid/amqp_0_10/Codecs.h b/qpid/cpp/include/qpid/amqp_0_10/Codecs.h
index 78b0aa671b..62370a0e5e 100644
--- a/qpid/cpp/include/qpid/amqp_0_10/Codecs.h
+++ b/qpid/cpp/include/qpid/amqp_0_10/Codecs.h
@@ -37,8 +37,9 @@ namespace amqp_0_10 {
 class QPID_COMMON_EXTERN MapCodec
 {
   public:
-    static void encode(const qpid::types::Variant::Map&, std::string&);
-    static void decode(const std::string&, qpid::types::Variant::Map&);
+    typedef qpid::types::Variant::Map ObjectType;
+    static void encode(const ObjectType&, std::string&);
+    static void decode(const std::string&, ObjectType&);
     static const std::string contentType;
   private:
 };
@@ -50,8 +51,9 @@ class QPID_COMMON_EXTERN MapCodec
 class QPID_COMMON_EXTERN ListCodec
 {
   public:
-    static void encode(const qpid::types::Variant::List&, std::string&);
-    static void decode(const std::string&, qpid::types::Variant::List&);
+    typedef qpid::types::Variant::List ObjectType;
+    static void encode(const ObjectType&, std::string&);
+    static void decode(const std::string&, ObjectType&);
     static const std::string contentType;
   private:
 };
diff --git a/qpid/cpp/src/qpid/messaging/Message.cpp b/qpid/cpp/src/qpid/messaging/Message.cpp
index bbbb257b18..753d3cec1b 100644
--- a/qpid/cpp/src/qpid/messaging/Message.cpp
+++ b/qpid/cpp/src/qpid/messaging/Message.cpp
@@ -83,56 +83,65 @@ size_t Message::getContentSize() const
     return impl->getBytes().size();
 }
 
-
 EncodingException::EncodingException(const std::string& msg) : qpid::Exception(msg) {}
 
 const std::string BAD_ENCODING("Unsupported encoding: %1% (only %2% is supported at present).");
 
-bool checkEncoding(const std::string& requested, const std::string& supported)
+template <class C> struct MessageCodec
 {
-    if (requested.size()) {
-        if (requested == supported) return true;
-        else throw EncodingException((boost::format(BAD_ENCODING) % requested % supported).str());
-    } else {
-        return false;
+    static bool checkEncoding(const std::string& requested)
+    {
+        if (requested.size()) {
+            if (requested == C::contentType) return true;
+            else throw EncodingException((boost::format(BAD_ENCODING) % requested % C::contentType).str());
+        } else {
+            return false;
+        }
+    }
+    
+    /*
+     * Currently only support a single encoding type for both list and
+     * map, based on AMQP 0-10, though wider support is anticipated in the
+     * future. This method simply checks that the desired encoding (if one
+     * is specified, either through the message-content or through an
+     * override) is indeed supported.
+     */
+    static void checkEncoding(const Message& message, const std::string& requested)
+    {
+        checkEncoding(requested) || checkEncoding(message.getContentType());
     }
-}
 
-/*
- * Currently only support a single encoding type for both list and
- * map, based on AMQP 0-10, though wider support is anticipated in the
- * future. This method simply checks that the desired encoding (if one
- * is specified, either through the message-content or through an
- * override) is indeed supported.
- */
-void checkEncoding(const Message& message, const std::string& requested, const std::string& supported)
-{
-    checkEncoding(requested, supported) || checkEncoding(message.getContentType(), supported);
-}
- 
+    template <class T> static void decode(const Message& message, T& object, const std::string& encoding)
+    {
+        checkEncoding(message, encoding);
+        C::decode(message.getContent(), object);
+    }
+
+    template <class T> static void encode(const T& map, Message& message, const std::string& encoding)
+    {
+        checkEncoding(message, encoding);
+        std::string content;
+        C::encode(map, content);
+        message.setContentType(C::contentType);
+        message.setContent(content);
+    }
+};
+
 void decode(const Message& message, Variant::Map& map, const std::string& encoding)
 {
-    checkEncoding(message, encoding, qpid::amqp_0_10::MapCodec::contentType);
-    qpid::amqp_0_10::MapCodec::decode(message.getContent(), map);
+    MessageCodec<qpid::amqp_0_10::MapCodec>::decode(message, map, encoding);
 }
 void decode(const Message& message, Variant::List& list, const std::string& encoding)
 {
-    checkEncoding(message, encoding, qpid::amqp_0_10::ListCodec::contentType);
-    qpid::amqp_0_10::ListCodec::decode(message.getContent(), list);
+    MessageCodec<qpid::amqp_0_10::ListCodec>::decode(message, list, encoding);
 }
 void encode(const Variant::Map& map, Message& message, const std::string& encoding)
 {
-    checkEncoding(message, encoding, qpid::amqp_0_10::MapCodec::contentType);
-    std::string content;
-    qpid::amqp_0_10::MapCodec::encode(map, content);
-    message.setContent(content);
+    MessageCodec<qpid::amqp_0_10::MapCodec>::encode(map, message, encoding);
 }
 void encode(const Variant::List& list, Message& message, const std::string& encoding)
 {
-    checkEncoding(message, encoding, qpid::amqp_0_10::ListCodec::contentType);
-    std::string content;
-    qpid::amqp_0_10::ListCodec::encode(list, content);
-    message.setContent(content);
+    MessageCodec<qpid::amqp_0_10::ListCodec>::encode(list, message, encoding);
 }
 
 }} // namespace qpid::messaging