[36] Override the ThreadContextMap in the provider.

src/main/java/org/jboss/logmanager/log4j/JBossLogger.java

@@ -20,7 +20,6 @@
 package org.jboss.logmanager.log4j;
 
 import java.util.Collections;
-import java.util.Iterator;
 
 import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.Marker;
@@ -175,14 +174,6 @@ private String getNdc() {
         if (contextStack.isEmpty()) {
             return "";
         }
-        final StringBuilder result = new StringBuilder();
-        final Iterator<String> iter = contextStack.iterator();
-        while (iter.hasNext()) {
-            result.append(iter.next());
-            if (iter.hasNext()) {
-                result.append('.');
-            }
-        }
-        return result.toString();
+        return String.join(".", contextStack);
     }
 }

src/main/java/org/jboss/logmanager/log4j/JBossProvider.java

@@ -20,6 +20,7 @@
 package org.jboss.logmanager.log4j;
 
 import org.apache.logging.log4j.spi.Provider;
+import org.apache.logging.log4j.spi.ThreadContextMap;
 
 /**
  * @author <a href="mailto:jperkins@redhat.com">James R. Perkins</a>
@@ -29,4 +30,14 @@ public class JBossProvider extends Provider {
     public JBossProvider() {
         super(500, "2.6.0", JBossLoggerContextFactory.class);
     }
+
+    @Override
+    public String getThreadContextMap() {
+        return ThreadContextMDCMap.class.getName();
+    }
+
+    @Override
+    public Class<? extends ThreadContextMap> loadThreadContextMap() {
+        return ThreadContextMDCMap.class;
+    }
 }

src/main/java/org/jboss/logmanager/log4j/ThreadContextMDCMap.java

@@ -0,0 +1,77 @@
+/*
+ * JBoss, Home of Professional Open Source.
+ *
+ * Copyright 2023 Red Hat, Inc., and individual contributors
+ * as indicated by the @author tags.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jboss.logmanager.log4j;
+
+import java.util.Map;
+
+import org.apache.logging.log4j.spi.ThreadContextMap;
+import org.jboss.logmanager.MDC;
+
+/**
+ * A {@link ThreadContextMap} implementation which delegates to {@link MDC}.
+ *
+ * @author <a href="mailto:jperkins@redhat.com">James R. Perkins</a>
+ */
+public class ThreadContextMDCMap implements ThreadContextMap {
+    @Override
+    public void clear() {
+        MDC.clear();
+    }
+
+    @Override
+    public boolean containsKey(final String key) {
+        return MDC.get(key) != null;
+    }
+
+    @Override
+    public String get(final String key) {
+        return MDC.get(key);
+    }
+
+    @Override
+    public Map<String, String> getCopy() {
+        return MDC.copy();
+    }
+
+    @Override
+    public Map<String, String> getImmutableMapOrNull() {
+        final Map<String, String> copy = MDC.copy();
+        return copy.isEmpty() ? null : Map.copyOf(copy);
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return MDC.isEmpty();
+    }
+
+    @Override
+    public void put(final String key, final String value) {
+        if (value == null) {
+            MDC.remove(key);
+        } else {
+            MDC.put(key, value);
+        }
+    }
+
+    @Override
+    public void remove(final String key) {
+        MDC.remove(key);
+    }
+}

src/test/java/org/jboss/logmanager/log4j/ThreadContextMapTestCase.java

@@ -22,17 +22,55 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.ThreadContext;
+import org.jboss.logmanager.MDC;
+import org.jboss.logmanager.NDC;
 import org.jboss.logmanager.formatters.PatternFormatter;
 import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import io.smallrye.common.constraint.Assert;
+
 /**
  * @author <a href="mailto:jperkins@redhat.com">James R. Perkins</a>
  */
 public class ThreadContextMapTestCase extends AbstractTestCase {
 
+    @BeforeEach
+    public void clear() {
+        ThreadContext.clearAll();
+        MDC.clear();
+        NDC.clear();
+    }
+
+    @Test
+    public void clearThreadContext() {
+        final String key = "test.clear.key";
+        ThreadContext.put(key, "test clear value");
+
+        Assertions.assertEquals("test clear value", ThreadContext.get(key));
+        Assertions.assertEquals("test clear value", MDC.get(key));
+
+        ThreadContext.clearMap();
+        Assert.assertTrue(ThreadContext.isEmpty());
+        Assert.assertTrue(MDC.isEmpty());
+    }
+
+    @Test
+    public void clearMdc() {
+        final String key = "test.clear.key";
+        ThreadContext.put(key, "test clear value");
+
+        Assertions.assertEquals("test clear value", ThreadContext.get(key));
+        Assertions.assertEquals("test clear value", MDC.get(key));
+
+        MDC.clear();
+        Assert.assertTrue(ThreadContext.isEmpty());
+        Assert.assertTrue(MDC.isEmpty());
+    }
+
     @Test
-    public void testPut() {
+    public void putThreadContext() {
         final String key = "test.key";
         final TestQueueHandler handler = new TestQueueHandler(new PatternFormatter("%X{" + key + "}"));
         org.jboss.logmanager.Logger.getLogger("").addHandler(handler);
@@ -51,7 +89,26 @@ public void testPut() {
     }
 
     @Test
-    public void testPush() {
+    public void putMdc() {
+        final String key = "test.key";
+        final TestQueueHandler handler = new TestQueueHandler(new PatternFormatter("%X{" + key + "}"));
+        org.jboss.logmanager.Logger.getLogger("").addHandler(handler);
+        MDC.put(key, "test value");
+
+        final Logger logger = LogManager.getLogger();
+
+        logger.info("Test message");
+
+        Assertions.assertEquals("test value", handler.pollFormatted());
+
+        ThreadContext.remove(key);
+
+        logger.info("Test message");
+        Assertions.assertEquals("", handler.pollFormatted());
+    }
+
+    @Test
+    public void pushThreadContext() {
         final TestQueueHandler handler = new TestQueueHandler(new PatternFormatter("%x"));
         org.jboss.logmanager.Logger.getLogger("").addHandler(handler);
 
@@ -71,4 +128,32 @@ public void testPush() {
         Assertions.assertEquals("value-1.value-2", handler.pollFormatted());
     }
 
+    @Test
+    public void removeThreadContext() {
+        final String key = "test.clear.key";
+        ThreadContext.put(key, "test clear value");
+
+        Assertions.assertEquals("test clear value", ThreadContext.get(key));
+        Assertions.assertEquals("test clear value", MDC.get(key));
+
+        ThreadContext.remove(key);
+
+        Assertions.assertNull(ThreadContext.get(key));
+        Assertions.assertNull(MDC.get(key));
+    }
+
+    @Test
+    public void removeMdc() {
+        final String key = "test.clear.key";
+        MDC.put(key, "test clear value");
+
+        Assertions.assertEquals("test clear value", ThreadContext.get(key));
+        Assertions.assertEquals("test clear value", MDC.get(key));
+
+        MDC.remove(key);
+
+        Assertions.assertNull(ThreadContext.get(key));
+        Assertions.assertNull(MDC.get(key));
+    }
+
 }