Index: /Users/orenmnero/Development/quickfixj/src/quickfix/FieldMap.java
===================================================================
--- /Users/orenmnero/Development/quickfixj/src/quickfix/FieldMap.java (revision 416)
+++ /Users/orenmnero/Development/quickfixj/src/quickfix/FieldMap.java (working copy)
@@ -71,6 +71,10 @@
         groups.clear();
     }
 
+ public boolean isEmpty() {
+ return fields.size() == 0;
+ }
+
     private class FieldOrderComparator implements Comparator, Serializable {
         static final long serialVersionUID = 3416006398018829270L;
 
Index: /Users/orenmnero/Development/quickfixj/src/quickfix/Message.java
===================================================================
--- /Users/orenmnero/Development/quickfixj/src/quickfix/Message.java (revision 416)
+++ /Users/orenmnero/Development/quickfixj/src/quickfix/Message.java (working copy)
@@ -305,6 +305,16 @@
         return !isAdmin();
     }
 
+ public boolean isEmpty() {
+ return super.isEmpty() && header.isEmpty() && trailer.isEmpty();
+ }
+
+ public void clear() {
+ super.clear();
+ header.clear();
+ trailer.clear();
+ }
+
     public class Header extends FieldMap {
 
         static final long serialVersionUID = -3193357271891865972L;
@@ -380,6 +390,10 @@
             parseHeader(dd);
             parseBody(dd);
             parseTrailer(dd);
+
+ if( isEmpty() ) {
+ throw new InvalidMessage( "Message contains no fields" );
+ }
         } catch (InvalidMessage e) {
             isValidStructure = false;
             throw e;
@@ -409,24 +423,30 @@
 
     private void parseHeader(DataDictionary dd) throws InvalidMessage {
         boolean invalidHeaderFieldOrder = false;
+
         StringField beginString = extractField(dd);
- if (beginString.getField() != BeginString.FIELD) {
+ if (beginString == null || beginString.getField() != BeginString.FIELD) {
             invalidHeaderFieldOrder = true;
+ } else {
+ header.setField(beginString);
         }
         StringField bodyLength = extractField(dd);
- if (bodyLength.getField() != BodyLength.FIELD) {
+ if (bodyLength == null || bodyLength.getField() != BodyLength.FIELD) {
             invalidHeaderFieldOrder = true;
+ } else {
+ header.setField( bodyLength );
         }
         StringField msgType = extractField(dd);
- if (msgType.getField() != MsgType.FIELD) {
+ if (msgType == null || msgType.getField() != MsgType.FIELD) {
             invalidHeaderFieldOrder = true;
+ } else {
+ header.setField( msgType );
         }
+
         if (doValidation && invalidHeaderFieldOrder) {
             throw new InvalidMessage("Header fields out of order");
         }
- header.setField(beginString);
- header.setField(bodyLength);
- header.setField(msgType);
+
         StringField field = extractField(dd);
         while (field != null && isHeaderField(field, dd)) {
             header.setField(field);
Index: /Users/orenmnero/Development/quickfixj/test/quickfix/MessageTest.java
===================================================================
--- /Users/orenmnero/Development/quickfixj/test/quickfix/MessageTest.java (revision 416)
+++ /Users/orenmnero/Development/quickfixj/test/quickfix/MessageTest.java (working copy)
@@ -287,6 +287,27 @@
         assertEquals("wrong value", "CAD", valueMessageType.getString(UnderlyingCurrency.FIELD));
     }
 
+ public void testParseEmptyString() throws Exception {
+ String data = "";
+
+ // with validation
+ try {
+ Message message = new Message(data, DataDictionaryTest.getDictionary());
+ } catch( NullPointerException npe ) {
+ fail("InvalidMessage expected, got NullPointerException" );
+ } catch( InvalidMessage im ) {
+ }
+
+ // without validation
+ try {
+ Message message = new Message(data, DataDictionaryTest.getDictionary(), false);
+ } catch( NullPointerException npe ) {
+ fail("InvalidMessage expected, got NullPointerException" );
+ } catch( InvalidMessage im ) {
+ }
+
+ }
+
     private void assertHeaderField(Message message, String expectedValue, int field)
             throws FieldNotFound {
         assertEquals(expectedValue, message.getHeader().getString(field));
@@ -473,6 +494,23 @@
         return numAllocs;
     }
 
+ public void testIsEmpty() {
+ Message message = new Message();
+ assertTrue("Message should be empty on construction", message.isEmpty());
+ message.getHeader().setField(new BeginString("FIX.4.2"));
+ assertFalse("Header should contain a field", message.isEmpty());
+ message.clear();
+ assertTrue("Message should be empty after clear", message.isEmpty());
+ message.setField(new Symbol("MSFT"));
+ assertFalse("Body should contain a field", message.isEmpty());
+ message.clear();
+ assertTrue("Message should be empty after clear", message.isEmpty());
+ message.getTrailer().setField(new CheckSum("10"));
+ assertFalse("Trailer should contain a field", message.isEmpty());
+ message.clear();
+ assertTrue("Message should be empty after clear", message.isEmpty());
+ }
+
     public void testMessageSetGetString() {
         Message message = new Message();