From 0a10e642954e41ece5d0f8b95438f5588b3d53bd Mon Sep 17 00:00:00 2001
From: Michael Simons <michael@simons.ac>
Date: Fri, 11 Sep 2020 15:22:00 +0200
Subject: [PATCH] DATAGRAPH-1376 - Make DefaultNeo4jClient compatible with
 GraalVM native.

- Remove the usage of MethodHandles
- Allow reflective access to the query runner interface.
---
 .../data/neo4j/core/DefaultNeo4jClient.java   | 20 +++++--------------
 .../spring-data-neo4j/native-image.properties |  1 +
 .../spring-data-neo4j/reflection-config.json  |  6 ++++++
 3 files changed, 12 insertions(+), 15 deletions(-)
 create mode 100644 src/main/resources/META-INF/native-image/org.springframework.data/spring-data-neo4j/native-image.properties
 create mode 100644 src/main/resources/META-INF/native-image/org.springframework.data/spring-data-neo4j/reflection-config.json

diff --git a/src/main/java/org/springframework/data/neo4j/core/DefaultNeo4jClient.java b/src/main/java/org/springframework/data/neo4j/core/DefaultNeo4jClient.java
index 77db9b107..2293b835f 100644
--- a/src/main/java/org/springframework/data/neo4j/core/DefaultNeo4jClient.java
+++ b/src/main/java/org/springframework/data/neo4j/core/DefaultNeo4jClient.java
@@ -15,15 +15,12 @@
  */
 package org.springframework.data.neo4j.core;
 
-import java.lang.invoke.MethodHandle;
-import java.lang.invoke.MethodHandles;
 import java.lang.reflect.InvocationHandler;
 import java.lang.reflect.Method;
 import java.lang.reflect.Proxy;
 import java.util.Collection;
 import java.util.Map;
 import java.util.Optional;
-import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.BiFunction;
 import java.util.function.Function;
 import java.util.function.Supplier;
@@ -94,7 +91,6 @@ class DefaultNeo4jClient implements Neo4jClient {
 
 	static class AutoCloseableQueryRunnerHandler implements InvocationHandler {
 
-		private final Map<Method, MethodHandle> cachedHandles = new ConcurrentHashMap<>();
 		private final QueryRunner target;
 
 		AutoCloseableQueryRunnerHandler(QueryRunner target) {
@@ -110,15 +106,7 @@ class DefaultNeo4jClient implements Neo4jClient {
 				}
 				return null;
 			} else {
-				return cachedHandles.computeIfAbsent(method, this::findHandleFor).invokeWithArguments(args);
-			}
-		}
-
-		MethodHandle findHandleFor(Method method) {
-			try {
-				return MethodHandles.publicLookup().unreflect(method).bindTo(target);
-			} catch (IllegalAccessException e) {
-				throw new RuntimeException(e);
+				return method.invoke(target, args);
 			}
 		}
 	}
@@ -178,7 +166,7 @@ class DefaultNeo4jClient implements Neo4jClient {
 	 * Tries to convert the given {@link RuntimeException} into a {@link DataAccessException} but returns the original
 	 * exception if the conversation failed. Thus allows safe re-throwing of the return value.
 	 *
-	 * @param ex the exception to translate
+	 * @param ex                  the exception to translate
 	 * @param exceptionTranslator the {@link PersistenceExceptionTranslator} to be used for translation
 	 * @return
 	 */
@@ -293,7 +281,9 @@ class DefaultNeo4jClient implements Neo4jClient {
 
 			try (AutoCloseableQueryRunner statementRunner = getQueryRunner(this.targetDatabase)) {
 				Result result = runnableStatement.runWith(statementRunner);
-				return result.hasNext() ? Optional.of(mappingFunction.apply(typeSystem, result.single())) : Optional.empty();
+				return result.hasNext() ?
+						Optional.of(mappingFunction.apply(typeSystem, result.single())) :
+						Optional.empty();
 			} catch (RuntimeException e) {
 				throw potentiallyConvertRuntimeException(e, persistenceExceptionTranslator);
 			}
diff --git a/src/main/resources/META-INF/native-image/org.springframework.data/spring-data-neo4j/native-image.properties b/src/main/resources/META-INF/native-image/org.springframework.data/spring-data-neo4j/native-image.properties
new file mode 100644
index 000000000..a5c05f6cd
--- /dev/null
+++ b/src/main/resources/META-INF/native-image/org.springframework.data/spring-data-neo4j/native-image.properties
@@ -0,0 +1 @@
+Args = -H:ReflectionConfigurationResources=${.}/reflection-config.json
diff --git a/src/main/resources/META-INF/native-image/org.springframework.data/spring-data-neo4j/reflection-config.json b/src/main/resources/META-INF/native-image/org.springframework.data/spring-data-neo4j/reflection-config.json
new file mode 100644
index 000000000..d4535a335
--- /dev/null
+++ b/src/main/resources/META-INF/native-image/org.springframework.data/spring-data-neo4j/reflection-config.json
@@ -0,0 +1,6 @@
+[
+  {
+    "name" : "org.neo4j.driver.QueryRunner",
+    "allDeclaredMethods" : true
+  }
+]