[Java] Validate message and field names are unique in context. Issue #470.

Author: mjpt777

sbe-tool/src/main/java/uk/co/real_logic/sbe/xml/Message.java

@@ -15,6 +15,7 @@
  */
 package uk.co.real_logic.sbe.xml;
 
+import org.agrona.collections.ObjectHashSet;
 import uk.co.real_logic.sbe.ir.Token;
 
 import org.w3c.dom.Node;
@@ -55,6 +56,7 @@ public class Message
     private final String semanticType;
     private final int computedBlockLength;
     private final Map<String, Type> typeByNameMap;
+    private final ObjectHashSet<String> names = new ObjectHashSet<>();
 
     /**
      * Construct a new message from XML Schema.
@@ -204,6 +206,11 @@ private List<Field> parseFieldsAndGroups(final Node node) throws XPathExpression
                     throw new IllegalStateException("Unknown node name: " + nodeName);
             }
 
+            if (!names.add(field.name()))
+            {
+                handleError(node, "duplicate name found: " + field.name());
+            }
+
             fieldList.add(field);
         }
 

sbe-tool/src/main/java/uk/co/real_logic/sbe/xml/XmlSchemaParser.java

@@ -16,6 +16,7 @@
  */
 package uk.co.real_logic.sbe.xml;
 
+import org.agrona.collections.ObjectHashSet;
 import org.w3c.dom.Document;
 import org.w3c.dom.Node;
 import org.w3c.dom.NodeList;
@@ -161,9 +162,10 @@ public static Map<Long, Message> findMessages(
         final Document document, final XPath xPath, final Map<String, Type> typeByNameMap) throws Exception
     {
         final Map<Long, Message> messageByIdMap = new HashMap<>();
+        final ObjectHashSet<String> names = new ObjectHashSet<>();
 
         forEach((NodeList)xPath.compile(MESSAGE_XPATH_EXPR).evaluate(document, XPathConstants.NODESET),
-            (node) -> addMessageWithIdCheck(messageByIdMap, new Message(node, typeByNameMap), node));
+            (node) -> addMessageWithIdCheck(names, messageByIdMap, new Message(node, typeByNameMap), node));
 
         return messageByIdMap;
     }
@@ -335,13 +337,21 @@ private static void addTypeWithNameCheck(final Map<String, Type> typeByNameMap,
     }
 
     private static void addMessageWithIdCheck(
-        final Map<Long, Message> messageByIdMap, final Message message, final Node node)
+        final ObjectHashSet<String> names,
+        final Map<Long, Message> messageByIdMap,
+        final Message message,
+        final Node node)
     {
         if (messageByIdMap.get((long)message.id()) != null)
         {
             handleError(node, "message template id already exists: " + message.id());
         }
 
+        if (!names.add(message.name()))
+        {
+            handleError(node, "message name already exists: " + message.name());
+        }
+
         checkForValidName(node, message.name());
 
         messageByIdMap.put((long)message.id(), message);