From 5ad6354e1540904fd0f19c58e2a670ba43706081 Mon Sep 17 00:00:00 2001
From: Darin Kelkhoff <darin.kelkhoff@gmail.com>
Date: Fri, 23 May 2025 12:00:36 -0500
Subject: [PATCH] Add isClassAvailable method (idea being to support optional
 maven dependencies!)

---
 .../backend/core/utils/ClassPathUtils.java    | 25 ++++++++++
 .../core/utils/ClassPathUtilsTest.java        | 47 +++++++++++++++++++
 2 files changed, 72 insertions(+)
 create mode 100644 qqq-backend-core/src/test/java/com/kingsrook/qqq/backend/core/utils/ClassPathUtilsTest.java

diff --git a/qqq-backend-core/src/main/java/com/kingsrook/qqq/backend/core/utils/ClassPathUtils.java b/qqq-backend-core/src/main/java/com/kingsrook/qqq/backend/core/utils/ClassPathUtils.java
index bcc42f2f..17f9c8fd 100644
--- a/qqq-backend-core/src/main/java/com/kingsrook/qqq/backend/core/utils/ClassPathUtils.java
+++ b/qqq-backend-core/src/main/java/com/kingsrook/qqq/backend/core/utils/ClassPathUtils.java
@@ -25,6 +25,8 @@ package com.kingsrook.qqq.backend.core.utils;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.reflect.ClassPath;
 
@@ -37,6 +39,29 @@ public class ClassPathUtils
 {
    private static ImmutableSet<ClassPath.ClassInfo> topLevelClasses;
 
+   private static final Map<String, Boolean> cache = new ConcurrentHashMap<>();
+
+
+
+   /***************************************************************************
+    **
+    ***************************************************************************/
+   public static boolean isClassAvailable(String className)
+   {
+      return cache.computeIfAbsent(className, c ->
+      {
+         try
+         {
+            Class.forName(c, false, ClassPathUtils.class.getClassLoader());
+            return true;
+         }
+         catch(ClassNotFoundException e)
+         {
+            return false;
+         }
+      });
+   }
+
 
 
    /*******************************************************************************
diff --git a/qqq-backend-core/src/test/java/com/kingsrook/qqq/backend/core/utils/ClassPathUtilsTest.java b/qqq-backend-core/src/test/java/com/kingsrook/qqq/backend/core/utils/ClassPathUtilsTest.java
new file mode 100644
index 00000000..ebdd257b
--- /dev/null
+++ b/qqq-backend-core/src/test/java/com/kingsrook/qqq/backend/core/utils/ClassPathUtilsTest.java
@@ -0,0 +1,47 @@
+/*
+ * QQQ - Low-code Application Framework for Engineers.
+ * Copyright (C) 2021-2025.  Kingsrook, LLC
+ * 651 N Broad St Ste 205 # 6917 | Middletown DE 19709 | United States
+ * contact@kingsrook.com
+ * https://github.com/Kingsrook/
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.kingsrook.qqq.backend.core.utils;
+
+
+import com.kingsrook.qqq.backend.core.BaseTest;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+
+/*******************************************************************************
+ ** Unit test for ClassPathUtils 
+ *******************************************************************************/
+class ClassPathUtilsTest extends BaseTest
+{
+
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   @Test
+   void test()
+   {
+      assertTrue(ClassPathUtils.isClassAvailable(ClassPathUtils.class.getName()));
+      assertFalse(ClassPathUtils.isClassAvailable("NOT-" + ClassPathUtils.class.getName()));
+   }
+
+}
\ No newline at end of file