ARTEMIS-1252 Add service loading of password codec to obtain its implementation from the app's root context

artemis-commons/src/main/java/org/apache/activemq/artemis/utils/PasswordMaskingUtil.java

@@ -20,6 +20,7 @@ import java.security.AccessController;
 import java.security.PrivilegedAction;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.ServiceLoader;
 
 import org.apache.activemq.artemis.api.core.ActiveMQException;
 import org.apache.activemq.artemis.api.core.ActiveMQExceptionType;
@@ -108,22 +109,33 @@ public final class PasswordMaskingUtil {
 
       // semi colons
       String[] parts = codecDesc.split(";");
-
       if (parts.length < 1)
          throw new ActiveMQException(ActiveMQExceptionType.ILLEGAL_STATE, "Invalid PasswordCodec value: " + codecDesc);
 
       final String codecClassName = parts[0];
 
       // load class
-      codecInstance = AccessController.doPrivileged(new PrivilegedAction<SensitiveDataCodec<String>>() {
-         @Override
-         public SensitiveDataCodec<String> run() {
-            ClassLoader loader = Thread.currentThread().getContextClassLoader();
+      codecInstance = AccessController.doPrivileged((PrivilegedAction<SensitiveDataCodec<String>>) () -> {
+         ServiceLoader<SensitiveDataCodec> serviceLoader = ServiceLoader.load(SensitiveDataCodec.class, PasswordMaskingUtil.class.getClassLoader());
+         try {
+            // Service load the codec, if a service is available
+            for (SensitiveDataCodec<String> codec : serviceLoader) {
+               if ((codec.getClass().getCanonicalName()).equals(codecClassName)) {
+                  return codec.getClass().newInstance();
+               }
+            }
+         } catch (Exception e) {
+            // Will ignore the exception and attempt to load the class directly
+         }
+         try {
+            // If a service is not available, load the codec class using this class's class loader
+            return (SensitiveDataCodec<String>) PasswordMaskingUtil.class.getClassLoader().loadClass(codecClassName).newInstance();
+         } catch (Exception e) {
             try {
-               Class<?> clazz = loader.loadClass(codecClassName);
-               return (SensitiveDataCodec<String>) clazz.newInstance();
-            } catch (Exception e) {
-               throw ActiveMQUtilBundle.BUNDLE.errorCreatingCodec(e, codecClassName);
+               // As a last resort, load the codec class using the current thread's context class loader
+               return (SensitiveDataCodec<String>) Thread.currentThread().getContextClassLoader().loadClass(codecClassName).newInstance();
+            } catch (Exception e2) {
+               throw ActiveMQUtilBundle.BUNDLE.errorCreatingCodec(e2, codecClassName);
             }
          }
       });

artemis-commons/src/test/java/org/apache/activemq/artemis/utils/PasswordMaskingUtilTest.java

@@ -0,0 +1,35 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.apache.activemq.artemis.utils;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertTrue;
+
+public class PasswordMaskingUtilTest {
+
+   @Test
+   public void testGetCodecUsingServiceLoader() throws Exception {
+      SensitiveDataCodec<String> codec = PasswordMaskingUtil.getCodec(PasswordMaskingUtil.getDefaultCodec().getClass().getCanonicalName());
+      assertTrue(codec instanceof DefaultSensitiveStringCodec);
+   }
+
+   @Test(expected = IllegalArgumentException.class)
+   public void testGetCodecUsingInvalidCodec() throws Exception {
+      PasswordMaskingUtil.getCodec("codec doesn't exist");
+   }
+}

artemis-commons/src/test/resources/META-INF/services/org.apache.activemq.artemis.utils.SensitiveDataCodec

@@ -0,0 +1 @@
+org.apache.activemq.artemis.utils.DefaultSensitiveStringCodec

docs/user-manual/en/configuration-index.md

@@ -464,11 +464,12 @@ If you don't want to use the jar-with-dependencies, make sure the classpath is c
 
 Just copy "80cf731af62c290" and replace your plaintext password with it.
 
-#### Using a different decoder
+#### Using a custom decoder
 
-It is possible to use a different decoder rather than the built-in one.
-Simply make sure the decoder is in Apache ActiveMQ Artemis's classpath and configure
-the server to use it as follows:
+It is possible to use a custom decoder rather than the built-in one.
+Simply make sure the decoder is in Apache ActiveMQ Artemis's classpath. The custom decoder
+can also be service loaded rather than class loaded, if the decoder's service provider is installed in the classpath.
+Then configure the server to use it as follows:
 
 ```xml
     <password-codec>com.foo.SomeDecoder;key1=value1;key2=value2</password-codec>