Enhancement: First field in repeating group as delimiter

quickfixj-base/src/main/java/quickfix/Message.java

@@ -733,7 +733,7 @@ private void parseGroup(String msgType, StringField field, DataDictionary dd, Da
             throw MessageUtils.newInvalidMessageException("Repeating group count requires an Integer but found '" + field.getValue() + "' in " + messageData, this);
         }
         parent.setField(groupCountTag, field);
-        final int firstField = rg.getDelimiterField();
+        int firstField = dds.isFirstFieldInGroupIsDelimiter() ? -1 : rg.getDelimiterField();
         Group group = null;
         boolean inGroupParse = true;
         while (inGroupParse) {
@@ -743,7 +743,9 @@ private void parseGroup(String msgType, StringField field, DataDictionary dd, Da
                 break;
             }
             int tag = field.getTag();
-            if (tag == firstField) {
+            boolean shouldCreateNewGroup = tag == firstField || (dds.isFirstFieldInGroupIsDelimiter() && firstField == -1);
+            if (shouldCreateNewGroup) {
+                firstField = tag;
                 addGroupRefToParent(group, parent);
                 group = new Group(groupCountTag, firstField, groupDataDictionary.getOrderedFields());
                 group.setField(field);

quickfixj-base/src/main/java/quickfix/ValidationSettings.java

@@ -25,6 +25,7 @@ public class ValidationSettings {
     boolean checkUserDefinedFields = true;
     boolean checkUnorderedGroupFields = true;
     boolean allowUnknownMessageFields = false;
+    boolean firstFieldInGroupIsDelimiter = false;
 
     public ValidationSettings() {}
 
@@ -34,6 +35,7 @@ public ValidationSettings(ValidationSettings validationSettings) {
         this.checkUserDefinedFields = validationSettings.checkUserDefinedFields;
         this.checkUnorderedGroupFields = validationSettings.checkUnorderedGroupFields;
         this.allowUnknownMessageFields = validationSettings.allowUnknownMessageFields;
+        this.firstFieldInGroupIsDelimiter = validationSettings.firstFieldInGroupIsDelimiter;
     }
 
     /**
@@ -65,6 +67,10 @@ public boolean isAllowUnknownMessageFields() {
         return allowUnknownMessageFields;
     }
 
+    public boolean isFirstFieldInGroupIsDelimiter() {
+        return firstFieldInGroupIsDelimiter;
+    }
+
     /**
      * Controls whether group fields are in the same order
      *
@@ -95,4 +101,15 @@ public void setCheckUserDefinedFields(boolean flag) {
     public void setAllowUnknownMessageFields(boolean allowUnknownFields) {
         allowUnknownMessageFields = allowUnknownFields;
     }
+
+    /**
+     * Controls whether any field which is
+     * first in the group would be used as delimiter
+     *
+     * @param flag true = use first field from message, false = follow data dictionary
+     * Must be used with disabled {@link #setCheckUnorderedGroupFields(boolean)}
+     */
+    public void setFirstFieldInGroupIsDelimiter(boolean flag) {
+        firstFieldInGroupIsDelimiter = flag;
+    }
 }

quickfixj-base/src/test/java/quickfix/ValidationSettingsTest.java

@@ -14,6 +14,7 @@ public void copyConstructor_retains_settings() {
         validationSettings.setCheckFieldsOutOfOrder(false);
         validationSettings.setCheckUnorderedGroupFields(false);
         validationSettings.setCheckUserDefinedFields(false);
+        validationSettings.setFirstFieldInGroupIsDelimiter(true);
 
         ValidationSettings validationSettingsCopy = new ValidationSettings(validationSettings);
 
@@ -22,5 +23,6 @@ public void copyConstructor_retains_settings() {
         assertEquals(validationSettingsCopy.isCheckFieldsOutOfOrder(), validationSettings.isCheckFieldsOutOfOrder());
         assertEquals(validationSettingsCopy.isCheckUnorderedGroupFields(), validationSettings.isCheckUnorderedGroupFields());
         assertEquals(validationSettingsCopy.isCheckUserDefinedFields(), validationSettings.isCheckUserDefinedFields());
+        assertEquals(validationSettingsCopy.isFirstFieldInGroupIsDelimiter(), validationSettings.isFirstFieldInGroupIsDelimiter());
     }
 }

quickfixj-core/src/main/doc/usermanual/usage/configuration.html

@@ -367,6 +367,14 @@ <H3>QuickFIX Settings</H3>
       N</TD>
     <TD>Y</TD>
   </TR>
+  <TR ALIGN="left" VALIGN="middle">
+    <TD><I>FirstFieldInGroupIsDelimiter</I></TD>
+    <TD>Session validation setting for enabling whether first found field in repeating group will be used as
+        delimiter. Values are "Y" or "N". Default is "N". ValidateUnorderedGroupFields should be set to "N"</TD>
+    <TD>Y<br>
+        N</TD>
+    <TD>N</TD>
+  </TR>
   <TR ALIGN="left" VALIGN="middle">
     <TD><I>ValidateIncomingMessage</I></TD>
     <TD>Allow to bypass the message validation (against the dictionary). Default is "Y".</TD>

quickfixj-core/src/main/java/quickfix/DefaultSessionFactory.java

@@ -21,6 +21,8 @@
 
 import org.quickfixj.QFJException;
 import org.quickfixj.SimpleCache;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import quickfix.field.ApplVerID;
 import quickfix.field.DefaultApplVerID;
 
@@ -37,6 +39,7 @@
  * initiators) for creating sessions.
  */
 public class DefaultSessionFactory implements SessionFactory {
+    private final static Logger log = LoggerFactory.getLogger(DefaultSessionFactory.class);
     private static final SimpleCache<String, DataDictionary> dictionaryCache = new SimpleCache<>(path -> {
         try {
             return new DataDictionary(path);
@@ -314,9 +317,23 @@ private ValidationSettings createValidationSettings(SessionID sessionID, Session
                     Session.SETTING_ALLOW_UNKNOWN_MSG_FIELDS));
         }
 
+        if (settings.isSetting(sessionID, Session.SETTING_FIRST_FIELD_IN_GROUP_IS_DELIMITER)) {
+            validationSettings.setFirstFieldInGroupIsDelimiter(settings.getBool(sessionID,
+                    Session.SETTING_FIRST_FIELD_IN_GROUP_IS_DELIMITER));
+        }
+
+        validateValidationSettings(validationSettings);
+
         return validationSettings;
     }
 
+    private void validateValidationSettings(ValidationSettings validationSettings) {
+        if (validationSettings.isFirstFieldInGroupIsDelimiter() && validationSettings.isCheckUnorderedGroupFields()) {
+            log.warn("Setting " + Session.SETTING_FIRST_FIELD_IN_GROUP_IS_DELIMITER
+                    + " requires " + Session.SETTING_VALIDATE_UNORDERED_GROUP_FIELDS + " to be set to false");
+        }
+    }
+
     private void processFixtDataDictionaries(SessionID sessionID, SessionSettings settings,
             DefaultDataDictionaryProvider dataDictionaryProvider) throws ConfigError,
             FieldConvertError {

quickfixj-core/src/main/java/quickfix/Session.java

@@ -208,6 +208,12 @@ public class Session implements Closeable {
      */
     public static final String SETTING_VALIDATE_UNORDERED_GROUP_FIELDS = "ValidateUnorderedGroupFields";
 
+    /**
+     * Session validation setting for enabling whether first found field in repeating group will be used as
+     * delimiter. Values are "Y" or "N". Default is "N".
+     */
+    public static final String SETTING_FIRST_FIELD_IN_GROUP_IS_DELIMITER = "FirstFieldInGroupIsDelimiter";
+
     /**
      * Session validation setting for enabling whether field values are
      * validated. Empty fields values are not allowed. Values are "Y" or "N".

quickfixj-core/src/test/java/quickfix/MessageTest.java

@@ -27,6 +27,9 @@
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
+import static org.junit.Assert.assertThrows;
+import static quickfix.DataDictionaryTest.getDictionary;
+
 import java.math.BigDecimal;
 import java.time.LocalDateTime;
 import java.time.ZoneOffset;
@@ -120,6 +123,7 @@
 import quickfix.fix44.ExecutionReport;
 import quickfix.fix44.IndicationOfInterest;
 import quickfix.fix44.Logon;
+import quickfix.fix44.NewOrderMultileg;
 import quickfix.fix44.Logon.NoMsgTypes;
 import quickfix.fix44.NewOrderCross;
 import quickfix.fix44.NewOrderSingle.NoPartyIDs;
@@ -1445,6 +1449,66 @@ public void testValidateFieldsOutOfOrderPreFIXT11() throws Exception {
         assertEquals(tcrOrdered.toString(), tcrUnOrdered.toString());
     }
 
+    @Test
+    public void testFirstFieldInGroupIsDelimiter() throws Exception {
+
+        final DataDictionary dataDictionary = new DataDictionary(getDictionary());
+        ValidationSettings validationSettings = new ValidationSettings();
+
+        String fixMsg = "8=FIX.4.4\u00019=688\u000135=AB\u000149=AAA\u000156=BBB\u000134=21133\u000150=ABCABC" +
+                "\u000152=20230905-13:24:37.022\u000155=AAPL\u00011=ACC1\u000111=123456abcedf\u000121=1\u000138=5\u000154=1\u000140=2\u000144=-0.8" +
+                "\u000159=0\u000160=20230905-13:24:36.984\u0001100=ALGO\u0001167=MLEG\u0001555=3\u0001602=111\u0001600=AAA" +
+                "\u0001602=222\u0001654=231\u0001600=BBB\u0001602=333\u0001654=332\u0001600=CCC\u000158=TEXT\u000110=168\u0001";
+
+        String byDictFixMsg = "8=FIX.4.4\u00019=688\u000135=AB\u000149=AAA\u000156=BBB\u000134=21133\u000150=ABCABC" +
+                "\u000152=20230905-13:24:37.022\u000155=AAPL\u00011=ACC1\u000111=123456abcedf\u000121=1\u000138=5\u000154=1\u000140=2\u000144=-0.8" +
+                "\u000159=0\u000160=20230905-13:24:36.984\u0001100=ALGO\u0001167=MLEG\u0001555=3\u0001600=AAA\u0001602=111" +
+                "\u0001600=BBB\u0001602=222\u0001654=231\u0001600=CCC\u0001602=333\u0001654=332\u000158=TEXT\u000110=168\u0001";
+
+        validationSettings.setFirstFieldInGroupIsDelimiter(true);
+        validationSettings.setCheckUnorderedGroupFields(false);
+        final NewOrderMultileg noml1 = new NewOrderMultileg();
+        noml1.fromString(fixMsg, dataDictionary, validationSettings, true);
+        dataDictionary.validate(noml1, validationSettings);
+        assertTrue(noml1.hasGroup(555));
+        assertEquals(3, noml1.getGroupCount(555));
+        //when firstFieldInGroupIsDelimiter = true and setCheckUnorderedGroupFields = false - valid
+        //delimiter should be first tag in group
+        assertEquals(602, noml1.getGroup(1, 555).delim());
+
+        validationSettings.setFirstFieldInGroupIsDelimiter(false);
+        validationSettings.setCheckUnorderedGroupFields(false);
+        final NewOrderMultileg noml2 = new NewOrderMultileg();
+        noml2.fromString(fixMsg, dataDictionary, validationSettings, true);
+        //when firstFieldInGroupIsDelimiter = false and setCheckUnorderedGroupFields = false - exception is thrown
+        assertThrows(FieldException.class, () -> dataDictionary.validate(noml2, validationSettings));
+
+        validationSettings.setFirstFieldInGroupIsDelimiter(false);
+        validationSettings.setCheckUnorderedGroupFields(true);
+        final NewOrderMultileg noml3 = new NewOrderMultileg();
+        noml3.fromString(fixMsg, dataDictionary, validationSettings, true);
+        //when firstFieldInGroupIsDelimiter = false and setCheckUnorderedGroupFields = true - exception is thrown
+        assertThrows(FieldException.class, () -> dataDictionary.validate(noml3, validationSettings));
+
+        validationSettings.setFirstFieldInGroupIsDelimiter(true);
+        validationSettings.setCheckUnorderedGroupFields(true);
+        final NewOrderMultileg noml4 = new NewOrderMultileg();
+        noml4.fromString(fixMsg, dataDictionary, validationSettings, true);
+        //when firstFieldInGroupIsDelimiter = true and setCheckUnorderedGroupFields = true - exception is thrown, since order of tags is incorrect.
+        assertThrows(FieldException.class, () -> dataDictionary.validate(noml4, validationSettings));
+
+        validationSettings.setFirstFieldInGroupIsDelimiter(true);
+        validationSettings.setCheckUnorderedGroupFields(true);
+        final NewOrderMultileg noml5 = new NewOrderMultileg();
+        noml5.fromString(byDictFixMsg, dataDictionary, validationSettings, true);
+        //when firstFieldInGroupIsDelimiter = true and setCheckUnorderedGroupFields = true, message aligns with dictionary - do NOT fail
+        dataDictionary.validate(noml5, validationSettings);
+        assertTrue(noml5.hasGroup(555));
+        assertEquals(3, noml5.getGroupCount(555));
+        //delimiter should be dictionary first tag = 600
+        assertEquals(600, noml5.getGroup(1, 555).delim());
+    }
+
     private void assertHeaderField(Message message, String expectedValue, int field)
             throws FieldNotFound {
         assertEquals(expectedValue, message.getHeader().getString(field));