From 9133cdb466ac952d9b0256386cf99c88652b12f2 Mon Sep 17 00:00:00 2001
From: Robbie Gemmell <robbie@apache.org>
Date: Tue, 3 Sep 2024 14:55:50 +0100
Subject: [PATCH] ARTEMIS-4962: add test, clarify some related comments

---
 .../artemis/api/core/FilterConstants.java     |  2 +-
 .../artemis/core/filter/impl/FilterImpl.java  |  3 +-
 .../artemis/core/filter/impl/FilterTest.java  | 29 +++++++++++++++++--
 3 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/artemis-core-client/src/main/java/org/apache/activemq/artemis/api/core/FilterConstants.java b/artemis-core-client/src/main/java/org/apache/activemq/artemis/api/core/FilterConstants.java
index e690ba602d..d50b7217e8 100644
--- a/artemis-core-client/src/main/java/org/apache/activemq/artemis/api/core/FilterConstants.java
+++ b/artemis-core-client/src/main/java/org/apache/activemq/artemis/api/core/FilterConstants.java
@@ -78,7 +78,7 @@ public final class FilterConstants {
    public static final SimpleString ACTIVEMQ_PREFIX = SimpleString.of("AMQ");
 
    /**
-    * Proton protocol stores JMSMessageID as NATIVE_MESSAGE_ID
+    * Core to AMQP wrapper can store JMSMessageID as NATIVE_MESSAGE_ID internally
     */
    public static final String NATIVE_MESSAGE_ID = "NATIVE_MESSAGE_ID";
 
diff --git a/artemis-server/src/main/java/org/apache/activemq/artemis/core/filter/impl/FilterImpl.java b/artemis-server/src/main/java/org/apache/activemq/artemis/core/filter/impl/FilterImpl.java
index 4246f7b4fe..3893d463f8 100644
--- a/artemis-server/src/main/java/org/apache/activemq/artemis/core/filter/impl/FilterImpl.java
+++ b/artemis-server/src/main/java/org/apache/activemq/artemis/core/filter/impl/FilterImpl.java
@@ -159,7 +159,8 @@ public class FilterImpl implements Filter {
    private static Object getHeaderFieldValue(final Message msg, final SimpleString fieldName) {
       if (FilterConstants.ACTIVEMQ_USERID.equals(fieldName)) {
          if (msg.getUserID() == null) {
-            // Proton stores JMSMessageID as NATIVE_MESSAGE_ID that is an arbitrary string
+            // Artemis can store JMSMessageID as NATIVE_MESSAGE_ID that is an arbitrary string,
+            // in wrapper used internally when converting from Core to AMQP.
             String amqpNativeID = msg.getStringProperty(NATIVE_MESSAGE_ID);
             if (amqpNativeID != null) {
                return SimpleString.of(amqpNativeID);
diff --git a/artemis-server/src/test/java/org/apache/activemq/artemis/core/filter/impl/FilterTest.java b/artemis-server/src/test/java/org/apache/activemq/artemis/core/filter/impl/FilterTest.java
index 8747a1155e..4c95171ecd 100644
--- a/artemis-server/src/test/java/org/apache/activemq/artemis/core/filter/impl/FilterTest.java
+++ b/artemis-server/src/test/java/org/apache/activemq/artemis/core/filter/impl/FilterTest.java
@@ -21,6 +21,8 @@ import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
 
+import java.util.UUID;
+
 import org.apache.activemq.artemis.api.core.ActiveMQException;
 import org.apache.activemq.artemis.api.core.ActiveMQInvalidFilterExpressionException;
 import org.apache.activemq.artemis.api.core.Message;
@@ -106,7 +108,6 @@ public class FilterTest extends SilentTestCase {
       message.setDurable(false);
 
       assertTrue(filter.match(message));
-
    }
 
    @Test
@@ -126,7 +127,6 @@ public class FilterTest extends SilentTestCase {
 
       assertFalse(lessThanSmall.match(message));
       assertFalse(moreThanLarge.match(message));
-
    }
 
    @Test
@@ -157,6 +157,31 @@ public class FilterTest extends SilentTestCase {
       assertTrue(filter.match(message));
    }
 
+   // AMQUserID, i.e. 'user-provided message ID', or what is typically thought of as the MessageID.
+   @Test
+   public void testAMQUserID() throws Exception {
+      // This 'MessageID' is the Artemis 'internal numeric id' assigned to each message
+      message = new CoreMessage().initBuffer(1024).setMessageID(1);
+
+      UUID randomUUID = UUID.randomUUID();
+      org.apache.activemq.artemis.utils.UUID artemisUUID = new org.apache.activemq.artemis.utils.UUID(randomUUID);
+
+      filter = FilterImpl.createFilter(SimpleString.of("AMQUserID='ID:" + randomUUID + "'"));
+      Filter nullFilter = FilterImpl.createFilter(SimpleString.of("AMQUserID IS NULL"));
+      Filter notNullFilter = FilterImpl.createFilter(SimpleString.of("AMQUserID IS NOT NULL"));
+
+      assertFalse(filter.match(message));
+      assertTrue(nullFilter.match(message));
+      assertFalse(notNullFilter.match(message));
+
+      // This 'UserID' is not about user names etc, but what is typically considered as a MessageID.
+      message.setUserID(artemisUUID);
+
+      assertTrue(filter.match(message));
+      assertFalse(nullFilter.match(message));
+      assertTrue(notNullFilter.match(message));
+   }
+
    @Test
    public void testBooleanTrue() throws Exception {
       filter = FilterImpl.createFilter(SimpleString.of("MyBoolean=true"));