From a73f428bc486c3013bdee2ebdfe795782508a35f Mon Sep 17 00:00:00 2001
From: Marc Baloup <marc.baloup@laposte.net>
Date: Sat, 7 Nov 2020 15:00:47 +0100
Subject: [PATCH] add ReflexionUtil.getAllSubclasses(Class) with 10 minutes
 cache (because it takes time to compute the result)

---
 pom.xml                                       | 32 +++++++++++++++++++
 .../java/fr/pandacube/util/ReflexionUtil.java | 30 +++++++++++++++++
 2 files changed, 62 insertions(+)

diff --git a/pom.xml b/pom.xml
index b841f65..a0fe38a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -33,5 +33,37 @@
             <version>1.2</version>
             <scope>compile</scope>
         </dependency>
+        <dependency>
+		    <groupId>io.github.classgraph</groupId>
+		    <artifactId>classgraph</artifactId>
+		    <version>4.8.90</version>
+            <scope>compile</scope>
+		</dependency>
     </dependencies>
+    
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-shade-plugin</artifactId>
+                <version>2.4.3</version>
+                
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>shade</goal>
+                        </goals>
+                        <configuration>
+                            <artifactSet>
+                                <includes>
+                                    <include>io.github.classgraph:classgraph</include>
+                                </includes>
+                            </artifactSet>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
 </project>
diff --git a/src/main/java/fr/pandacube/util/ReflexionUtil.java b/src/main/java/fr/pandacube/util/ReflexionUtil.java
index c087699..a07474c 100644
--- a/src/main/java/fr/pandacube/util/ReflexionUtil.java
+++ b/src/main/java/fr/pandacube/util/ReflexionUtil.java
@@ -2,6 +2,15 @@ package fr.pandacube.util;
 
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
+import java.util.List;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+
+import com.google.common.cache.Cache;
+import com.google.common.cache.CacheBuilder;
+
+import io.github.classgraph.ClassGraph;
+import io.github.classgraph.ScanResult;
 
 public class ReflexionUtil {
 
@@ -150,6 +159,27 @@ public class ReflexionUtil {
 	
 	
 	
+	private static Cache<Class<?>, List<Class<?>>> subClassesLists = CacheBuilder.newBuilder()
+			.expireAfterAccess(10, TimeUnit.MINUTES)
+			.build();
+	
+	public static <E> List<Class<? extends E>> getAllSubclasses(Class<E> clazz) {
+		try {
+			@SuppressWarnings("unchecked")
+			List<Class<? extends E>> classes = (List<Class<? extends E>>) (List<?>) subClassesLists.get(clazz, () -> {
+				try (ScanResult scanResult = new ClassGraph().enableClassInfo().ignoreClassVisibility().scan()) {
+					return scanResult.getSubclasses(clazz.getName()).loadClasses();
+				}
+			});
+			return classes;
+		} catch(ExecutionException e) {
+			Log.severe(e);
+			return null;
+		}
+		
+	}
+	
+	
 	
 
 }