2 files changed, 84 insertions, 44 deletions

diff --git a/src/main/java/org/traccar/ServerManager.java b/src/main/java/org/traccar/ServerManager.java
index 0db786bdb..2e2cf7cff 100644
--- a/src/main/java/org/traccar/ServerManager.java
+++ b/src/main/java/org/traccar/ServerManager.java
@@ -18,23 +18,16 @@ package org.traccar;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.traccar.config.Keys;
+import org.traccar.helper.ClassScanner;
 
-import java.io.File;
 import java.io.IOException;
 import java.net.BindException;
 import java.net.ConnectException;
-import java.net.URI;
 import java.net.URISyntaxException;
-import java.net.URL;
-import java.net.URLDecoder;
-import java.nio.charset.StandardCharsets;
-import java.util.Enumeration;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.jar.JarEntry;
-import java.util.jar.JarFile;
 
 public class ServerManager {
 
@@ -43,38 +36,9 @@ public class ServerManager {
     private final List<TrackerConnector> connectorList = new LinkedList<>();
     private final Map<String, BaseProtocol> protocolList = new ConcurrentHashMap<>();
 
-    private void loadPackage(String packageName) throws IOException, URISyntaxException, ReflectiveOperationException {
-
-        List<String> names = new LinkedList<>();
-        String packagePath = packageName.replace('.', '/');
-        URL packageUrl = getClass().getClassLoader().getResource(packagePath);
-
-        if (packageUrl.getProtocol().equals("jar")) {
-            String jarFileName = URLDecoder.decode(packageUrl.getFile(), StandardCharsets.UTF_8.name());
-            try (JarFile jf = new JarFile(jarFileName.substring(5, jarFileName.indexOf("!")))) {
-                Enumeration<JarEntry> jarEntries = jf.entries();
-                while (jarEntries.hasMoreElements()) {
-                    String entryName = jarEntries.nextElement().getName();
-                    if (entryName.startsWith(packagePath) && entryName.length() > packagePath.length() + 5) {
-                        names.add(entryName.substring(packagePath.length() + 1, entryName.lastIndexOf('.')));
-                    }
-                }
-            }
-        } else {
-            File folder = new File(new URI(packageUrl.toString()));
-            File[] files = folder.listFiles();
-            if (files != null) {
-                for (File actual: files) {
-                    String entryName = actual.getName();
-                    names.add(entryName.substring(0, entryName.lastIndexOf('.')));
-                }
-            }
-        }
-
-        for (String name : names) {
-            Class<?> protocolClass = Class.forName(packageName + '.' + name);
-            if (BaseProtocol.class.isAssignableFrom(protocolClass) && Context.getConfig().hasKey(
-                    Keys.PROTOCOL_PORT.withPrefix(BaseProtocol.nameFromClass(protocolClass)))) {
+    public ServerManager() throws IOException, URISyntaxException, ReflectiveOperationException {
+        for (Class<?> protocolClass : ClassScanner.findSubclasses(BaseProtocol.class, "org.traccar.protocol")) {
+            if (Context.getConfig().hasKey(Keys.PROTOCOL_PORT.withPrefix(BaseProtocol.nameFromClass(protocolClass)))) {
                 BaseProtocol protocol = (BaseProtocol) protocolClass.getDeclaredConstructor().newInstance();
                 connectorList.addAll(protocol.getConnectorList());
                 protocolList.put(protocol.getName(), protocol);
@@ -82,10 +46,6 @@ public class ServerManager {
         }
     }
 
-    public ServerManager() throws IOException, URISyntaxException, ReflectiveOperationException {
-        loadPackage("org.traccar.protocol");
-    }
-
     public BaseProtocol getProtocol(String name) {
         return protocolList.get(name);
     }
diff --git a/src/main/java/org/traccar/helper/ClassScanner.java b/src/main/java/org/traccar/helper/ClassScanner.java
new file mode 100644
index 000000000..c928f6a12
--- /dev/null
+++ b/src/main/java/org/traccar/helper/ClassScanner.java
@@ -0,0 +1,80 @@
+/*
+ * Copyright 2022 Anton Tananaev (anton@traccar.org)
+ *
+ * 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.traccar.helper;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.URL;
+import java.net.URLDecoder;
+import java.nio.charset.StandardCharsets;
+import java.util.Enumeration;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+
+public final class ClassScanner {
+
+    private ClassScanner() {
+    }
+
+    public static List<Class<?>> findSubclasses(
+            Class<?> baseClass) throws IOException, URISyntaxException, ReflectiveOperationException {
+        return findSubclasses(baseClass, baseClass.getPackageName());
+    }
+
+    public static List<Class<?>> findSubclasses(Class<?> baseClass, String packageName)
+            throws IOException, URISyntaxException, ReflectiveOperationException {
+
+        List<String> names = new LinkedList<>();
+        String packagePath = packageName.replace('.', '/');
+        URL packageUrl = baseClass.getClassLoader().getResource(packagePath);
+
+        if (packageUrl.getProtocol().equals("jar")) {
+            String jarFileName = URLDecoder.decode(packageUrl.getFile(), StandardCharsets.UTF_8.name());
+            try (JarFile jf = new JarFile(jarFileName.substring(5, jarFileName.indexOf("!")))) {
+                Enumeration<JarEntry> jarEntries = jf.entries();
+                while (jarEntries.hasMoreElements()) {
+                    String entryName = jarEntries.nextElement().getName();
+                    if (entryName.startsWith(packagePath) && entryName.length() > packagePath.length() + 5) {
+                        names.add(entryName.substring(packagePath.length() + 1, entryName.lastIndexOf('.')));
+                    }
+                }
+            }
+        } else {
+            File folder = new File(new URI(packageUrl.toString()));
+            File[] files = folder.listFiles();
+            if (files != null) {
+                for (File actual: files) {
+                    String entryName = actual.getName();
+                    names.add(entryName.substring(0, entryName.lastIndexOf('.')));
+                }
+            }
+        }
+
+        var classes = new LinkedList<Class<?>>();
+        for (String name : names) {
+            var clazz = Class.forName(packageName + '.' + name);
+            if (baseClass.isAssignableFrom(clazz)) {
+                classes.add(clazz);
+            }
+        }
+        return classes;
+    }
+
+}