Implement automatic loading of jar extensions

compiler/core/src/zserio/tools/ExtensionManager.java

@@ -1,8 +1,14 @@
 package zserio.tools;
 
+import java.io.File;
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.io.StringWriter;
+import java.io.UnsupportedEncodingException;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.net.URLDecoder;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Iterator;
@@ -24,9 +30,11 @@ final class ExtensionManager
      */
     public ExtensionManager(CommandLineArguments commandLineArguments)
     {
+        final URLClassLoader urlClassLoader = getUrlClassLoader();
+        final ClassLoader classLoader = (urlClassLoader != null) ? urlClassLoader : getClass().getClassLoader();
         extensions = new ArrayList<Extension>();
         this.commandLineArguments = commandLineArguments;
-        ServiceLoader<Extension> loader = ServiceLoader.load(Extension.class, getClass().getClassLoader());
+        ServiceLoader<Extension> loader = ServiceLoader.load(Extension.class, classLoader);
         Iterator<Extension> it = loader.iterator();
         while (it.hasNext())
         {
@@ -94,6 +102,80 @@ public void callExtensions(Root rootNode, ExtensionParameters parameters) throws
         }
     }
 
+    private URLClassLoader getUrlClassLoader()
+    {
+        final String workingDirectory = getWorkingDirectory();
+        if (workingDirectory == null)
+            return null;
+
+        final File[] fileList = new File(workingDirectory).listFiles();
+        if (fileList == null)
+            return null;
+
+        final ArrayList<URL> urlArray = new ArrayList<URL>();
+        try
+        {
+            for (File file : fileList)
+            {
+                if (isFileZserioExtension(file))
+                {
+                    System.out.println("File = " + file);
+                    urlArray.add(new URL("file:" + file.getPath()));
+                }
+            }
+        }
+        catch (MalformedURLException excpt)
+        {
+            return null;
+        }
+
+        final URLClassLoader urlClassLoader = new URLClassLoader(urlArray.toArray(new URL[0]));
+
+        return urlClassLoader;
+    }
+
+    private String getWorkingDirectory()
+    {
+        final String execPath = getClass().getProtectionDomain().getCodeSource().getLocation().getPath();
+        String decodedExecPath = null;
+        try
+        {
+            decodedExecPath = URLDecoder.decode(execPath, "UTF-8");
+        }
+        catch (UnsupportedEncodingException excpt)
+        {
+            return null;
+        }
+
+        final String workingDirectory = new File(decodedExecPath).getParent();
+
+        return workingDirectory;
+    }
+
+    private boolean isFileZserioExtension(File file)
+    {
+        if (!file.isFile())
+            return false;
+
+        final String fileName = file.getName();
+        if (!fileName.endsWith(".jar"))
+            return false;
+
+        if (!fileName.startsWith("zserio_"))
+            return false;
+
+        if (fileName.equals("zserio_core.jar"))
+            return false;
+
+        if (fileName.endsWith("_javadocs.jar"))
+            return false;
+
+        if (fileName.endsWith("_sources.jar"))
+            return false;
+
+        return true;
+    }
+
     private static void check(Root rootNode, Extension extension, ExtensionParameters parameters)
             throws ZserioExtensionException
     {