From 1bc7725230d86e9e9348146249d2fa885c88e371 Mon Sep 17 00:00:00 2001
From: Karl Schrab <karl.schrab@fokus.fraunhofer.de>
Date: Wed, 19 Jul 2023 18:06:16 +0200
Subject: [PATCH] feat: allow to set a classloader for
 PackageSpecificTypeAdapter

Signed-off-by: Karl Schrab <karl.schrab@fokus.fraunhofer.de>
---
 .../util/gson/PackageSpecificTypeAdapter.java | 41 ++++++++++++++++++-
 1 file changed, 39 insertions(+), 2 deletions(-)

diff --git a/lib/mosaic-utils/src/main/java/org/eclipse/mosaic/lib/util/gson/PackageSpecificTypeAdapter.java b/lib/mosaic-utils/src/main/java/org/eclipse/mosaic/lib/util/gson/PackageSpecificTypeAdapter.java
index a5ea0bda8..f6c296bec 100644
--- a/lib/mosaic-utils/src/main/java/org/eclipse/mosaic/lib/util/gson/PackageSpecificTypeAdapter.java
+++ b/lib/mosaic-utils/src/main/java/org/eclipse/mosaic/lib/util/gson/PackageSpecificTypeAdapter.java
@@ -20,36 +20,73 @@
 import com.google.gson.Gson;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapterFactory;
+import org.apache.commons.lang3.Validate;
 
 import java.util.LinkedList;
 import java.util.List;
 
-public class PackageSpecificTypeAdapter<T> extends AbstractTypeAdapterFactory<T> {
+/**
+ * This {@link TypeAdapterFactory} allows to create an object from JSON definition
+ * based on a "type" attribute. According to the value of the value in the "type" attribute,
+ * a class is loaded and an object of this class is instantiated. Since this explicitly works
+ * with simple class names only, a search space of possible packages need to be defined, which
+ * are used to resolve the actual class.
+ */
+public final class PackageSpecificTypeAdapter<T> extends AbstractTypeAdapterFactory<T> {
+
+    /**
+     * Holds all package names which are used to search for suitable classes to instantiate based on the given type name.
+     */
     private final List<String> packageNames = new LinkedList<>();
 
+    /**
+     * The class loader to load the given class from.
+     */
+    private ClassLoader classLoader = PackageSpecificTypeAdapter.class.getClassLoader();
+
     public PackageSpecificTypeAdapter(TypeAdapterFactory parentFactory, Gson gson) {
         super(parentFactory, gson);
     }
 
+    /**
+     * Adds the package of the given class to the search space. All classes within this package
+     * are candidates to be loaded by a given type name.
+     */
     public PackageSpecificTypeAdapter<T> searchInPackageOfClass(Class<?> clazz) {
         return searchInPackage(clazz.getPackage());
     }
 
+    /**
+     * Adds the given package to the search space. All classes within this package
+     * are candidates to be loaded by a given type name.
+     */
     public PackageSpecificTypeAdapter<T> searchInPackage(Package searchPackage) {
         return searchInPackage(searchPackage.getName());
     }
 
+    /**
+     * Adds the given fully qualified package name to the search space. All classes
+     * within the given package are candidates to be loaded by a given type name.
+     */
     public PackageSpecificTypeAdapter<T> searchInPackage(String packageName) {
         packageNames.add(packageName);
         return this;
     }
 
+    /**
+     * Defines a specific class loader from which the searched classes are loaded.
+     */
+    public PackageSpecificTypeAdapter<T> withClassLoader(ClassLoader classLoader) {
+        this.classLoader = Validate.notNull(classLoader, "Given class loader must not be null");
+        return this;
+    }
+
     @Override
     protected Class<?> fromTypeName(String type) {
         Class<?> returnClass = null;
         for (String searchPackage : packageNames) {
             try {
-                returnClass = Class.forName(searchPackage + "." + type);
+                returnClass = classLoader.loadClass(searchPackage + "." + type);
             } catch (ClassNotFoundException ignored) {
                 // nop
             }