Use MethodHandles for invoking methods/field getters

MethodHandles are faster and safer than Reflection
arteam · Oct 24, 2021 · 9cae313 · 9cae313
1 parent 83abe00
commit 9cae313
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Showing 3 changed files with 52 additions and 19 deletions.
diff --git a/server/src/main/java/com/github/arteam/simplejsonrpc/server/JsonRpcServer.java b/server/src/main/java/com/github/arteam/simplejsonrpc/server/JsonRpcServer.java
@@ -314,7 +314,12 @@ private Response handleSingle(@NotNull Request request, @NotNull Object service)
             return new ErrorResponse(id, INVALID_PARAMS);
         }
 
-        Object result = method.getMethod().invoke(service, methodParams);
+        Object result;
+        try {
+            result = method.getMethodHandle().bindTo(service).invokeWithArguments(methodParams);
+        } catch (Throwable e) {
+            throw new RuntimeException(e);
+        }
         return new SuccessResponse(id, result);
     }
 

diff --git a/server/src/main/java/com/github/arteam/simplejsonrpc/server/Reflections.java b/server/src/main/java/com/github/arteam/simplejsonrpc/server/Reflections.java
@@ -16,6 +16,8 @@
 import org.slf4j.LoggerFactory;
 
 import java.lang.annotation.Annotation;
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
@@ -30,6 +32,7 @@
 class Reflections {
 
     private static final Logger log = LoggerFactory.getLogger(JsonRpcServer.class);
+    private static final MethodHandles.Lookup METHOD_HANDLES_LOOKUP = MethodHandles.lookup();
 
     private Reflections() {
     }
@@ -67,7 +70,6 @@ public static <T extends Annotation> T getAnnotation(@Nullable Annotation[] anno
     @NotNull
     public static ClassMetadata getClassMetadata(@NotNull Class<?> clazz) {
         ImmutableMap.Builder<String, MethodMetadata> methodsMetadata = ImmutableMap.builder();
-
         Class<?> searchType = clazz;
         // Search through the class hierarchy
         while (searchType != null) {
@@ -98,7 +100,13 @@ public static ClassMetadata getClassMetadata(@NotNull Class<?> clazz) {
                 }
 
                 method.setAccessible(true);
-                methodsMetadata.put(rpcMethodName, new MethodMetadata(rpcMethodName, method, methodParams));
+                MethodHandle methodHandle;
+                try {
+                    methodHandle = METHOD_HANDLES_LOOKUP.unreflect(method);
+                } catch (IllegalAccessException e) {
+                    throw new RuntimeException(e);
+                }
+                methodsMetadata.put(rpcMethodName, new MethodMetadata(rpcMethodName, methodHandle, methodParams));
             }
             searchType = searchType.getSuperclass();
         }
@@ -152,8 +160,8 @@ private static ImmutableMap<String, ParameterMetadata> getMethodParameters(@NotN
 
     static ErrorDataResolver buildErrorDataResolver(Class<? extends Throwable> throwableClass) {
         Class<?> c = throwableClass;
-        Field dataField = null;
-        Method dataMethod = null;
+        MethodHandle dataField = null;
+        MethodHandle dataMethod = null;
         while (c != null) {
             for (Field field : c.getDeclaredFields()) {
                 if (field.isAnnotationPresent(JsonRpcErrorData.class)) {
@@ -162,7 +170,11 @@ static ErrorDataResolver buildErrorDataResolver(Class<? extends Throwable> throw
                                 "@JsonRpcErrorData annotated property in " + c.getName());
                     }
                     field.setAccessible(true);
-                    dataField = field;
+                    try {
+                        dataField = METHOD_HANDLES_LOOKUP.unreflectGetter(field);
+                    } catch (IllegalAccessException e) {
+                        throw new IllegalStateException(e);
+                    }
                 }
             }
             for (Method method : c.getDeclaredMethods()) {
@@ -180,17 +192,33 @@ static ErrorDataResolver buildErrorDataResolver(Class<? extends Throwable> throw
                                 "@JsonRpcErrorData annotated property in " + c.getName());
                     }
                     method.setAccessible(true);
-                    dataMethod = method;
+                    try {
+                        dataMethod = METHOD_HANDLES_LOOKUP.unreflect(method);
+                    } catch (IllegalAccessException e) {
+                        throw new RuntimeException(e);
+                    }
                 }
             }
             c = c.getSuperclass();
         }
         if (dataField != null) {
-            Field finalDataField = dataField;
-            return t -> Optional.ofNullable(finalDataField.get(t));
+            MethodHandle finalDataField = dataField;
+            return t -> {
+                try {
+                    return Optional.ofNullable(finalDataField.invoke(t));
+                } catch (Throwable e) {
+                    throw new IllegalStateException(e);
+                }
+            };
         } else if (dataMethod != null) {
-            Method finalDataMethod = dataMethod;
-            return t -> Optional.ofNullable(finalDataMethod.invoke(t));
+            MethodHandle finalDataMethod = dataMethod;
+            return t -> {
+                try {
+                    return Optional.ofNullable(finalDataMethod.invoke(t));
+                } catch (Throwable e) {
+                    throw new IllegalStateException(e);
+                }
+            };
         } else {
             return t -> Optional.empty();
         }

diff --git a/server/src/main/java/com/github/arteam/simplejsonrpc/server/metadata/MethodMetadata.java b/server/src/main/java/com/github/arteam/simplejsonrpc/server/metadata/MethodMetadata.java
@@ -4,7 +4,7 @@
 import com.google.common.collect.ImmutableMap;
 import org.jetbrains.annotations.NotNull;
 
-import java.lang.reflect.Method;
+import java.lang.invoke.MethodHandle;
 
 /**
  * Date: 8/1/14
@@ -20,21 +20,21 @@ public class MethodMetadata {
     private final String name;
 
     /**
-     * Actual method
+     * Actual method handle
      */
     @NotNull
-    private final Method method;
+    private final MethodHandle methodHandle;
 
     /**
      * Map of method params by RPC name
      */
     @NotNull
     private final ImmutableMap<String, ParameterMetadata> params;
 
-    public MethodMetadata(@NotNull String name, @NotNull Method method,
+    public MethodMetadata(@NotNull String name, @NotNull MethodHandle methodHandle,
                           @NotNull ImmutableMap<String, ParameterMetadata> params) {
         this.name = name;
-        this.method = method;
+        this.methodHandle = methodHandle;
         this.params = params;
     }
 
@@ -44,8 +44,8 @@ public String getName() {
     }
 
     @NotNull
-    public Method getMethod() {
-        return method;
+    public MethodHandle getMethodHandle() {
+        return methodHandle;
     }
 
     @NotNull
@@ -57,7 +57,7 @@ public ImmutableMap<String, ParameterMetadata> getParams() {
     public String toString() {
         return MoreObjects.toStringHelper(this)
                 .add("name", name)
-                .add("method", method)
+                .add("method", methodHandle)
                 .add("params", params)
                 .toString();
     }