Add LambdaMetafactory support to call simple getters efficiently

Author: soumik.dutta

src/main/java/io/leangen/graphql/metadata/execution/FixedLambdaInvoker.java

@@ -0,0 +1,22 @@
+package io.leangen.graphql.metadata.execution;
+
+import java.lang.reflect.AnnotatedType;
+import java.lang.reflect.Method;
+import java.util.function.Supplier;
+
+/**
+ * Created by soumik.dutta on 9/21/24.
+ */
+public class FixedLambdaInvoker extends LambdaInvoker {
+    final private Supplier<Object> targetSupplier;
+
+    public FixedLambdaInvoker(final Supplier<Object> targetSupplier, final Method resolverMethod, final AnnotatedType enclosingType, final boolean useSetAccessible) throws Exception {
+        super(resolverMethod, enclosingType, useSetAccessible);
+        this.targetSupplier = targetSupplier;
+    }
+
+    @Override
+    public Object execute(final Object target, final Object[] arguments) {
+        return this.lambdaGetter.apply(this.targetSupplier.get());
+    }
+}

src/main/java/io/leangen/graphql/metadata/execution/LambdaInvoker.java

@@ -0,0 +1,94 @@
+package io.leangen.graphql.metadata.execution;
+
+import io.leangen.graphql.util.ClassUtils;
+
+import java.lang.invoke.*;
+import java.lang.reflect.AnnotatedType;
+import java.lang.reflect.Method;
+import java.lang.reflect.Parameter;
+import java.util.Optional;
+import java.util.function.Function;
+
+/**
+ * Created by soumik.dutta on 9/21/24.
+ */
+public class LambdaInvoker extends Executable<Method> {
+    private static final Parameter[] NO_PARAMETERS = {};
+    private static final AnnotatedType[] NO_ANNOTATED_TYPES = {};
+    final Function<Object, Object> lambdaGetter;
+    private final AnnotatedType returnType;
+
+
+    public LambdaInvoker(final Method resolverMethod, final AnnotatedType enclosingType, final boolean useSetAccessible) throws Exception {
+        this.delegate = resolverMethod;
+        this.returnType = resolveReturnType(enclosingType);
+        final Optional<Function<Object, Object>> getter = createGetter(resolverMethod, useSetAccessible);
+        if (getter.isEmpty()) {
+            throw new Exception("Cannot create a lambda getter for " + resolverMethod.getName());
+        }
+
+        this.lambdaGetter = getter.get();
+    }
+
+    public static Optional<Function<Object, Object>> createGetter(final Method method, final boolean useSetAccessible) throws Exception {
+        if (method != null) {
+            if (method.getParameterCount() > 0) {
+                throw new Exception(method.getName() + " requires more than one argument");
+            }
+
+            try {
+                method.setAccessible(useSetAccessible);
+                MethodHandles.Lookup lookupMe = MethodHandles.lookup();
+                MethodHandles.Lookup lookup = MethodHandles.privateLookupIn(method.getDeclaringClass(), lookupMe);
+                MethodHandle virtualMethodHandle = lookup.unreflect(method);
+
+                CallSite site = LambdaMetafactory.metafactory(lookup, "apply", MethodType.methodType(Function.class),
+                        MethodType.methodType(Object.class, Object.class), virtualMethodHandle,
+                        MethodType.methodType(method.getReturnType(), method.getDeclaringClass()));
+
+                @SuppressWarnings("unchecked") Function<Object, Object> getterFunction = (Function<Object, Object>) site.getTarget()
+                        .invokeExact();
+                return Optional.of(getterFunction);
+            } catch (Throwable e) {
+                //
+                // if we cant make a dynamic lambda here, then we give up and let the old property fetching code do its thing
+                // this can happen on runtimes such as GraalVM native where LambdaMetafactory is not supported
+                // and will throw something like :
+                //
+                //    com.oracle.svm.core.jdk.UnsupportedFeatureError: Defining hidden classes at runtime is not supported.
+                //        at org.graalvm.nativeimage.builder/com.oracle.svm.core.util.VMError.unsupportedFeature(VMError.java:89)
+            }
+        }
+        return Optional.empty();
+    }
+
+    @Override
+    public Object execute(final Object target, final Object[] args) {
+        return lambdaGetter.apply(target);
+    }
+
+    @Override
+    final public AnnotatedType getReturnType() {
+        return returnType;
+    }
+
+    private AnnotatedType resolveReturnType(final AnnotatedType enclosingType) {
+        return ClassUtils.getReturnType(delegate, enclosingType);
+    }
+
+
+    @Override
+    final public int getParameterCount() {
+        return 0;
+    }
+
+    @Override
+    final public AnnotatedType[] getAnnotatedParameterTypes() {
+        return NO_ANNOTATED_TYPES;
+    }
+
+    @Override
+    final public Parameter[] getParameters() {
+        return NO_PARAMETERS;
+    }
+}

src/main/java/io/leangen/graphql/metadata/strategy/query/DefaultMethodInvokerFactory.java

@@ -1,17 +1,32 @@
 package io.leangen.graphql.metadata.strategy.query;
 
-import io.leangen.graphql.metadata.execution.Executable;
-import io.leangen.graphql.metadata.execution.FixedMethodInvoker;
-import io.leangen.graphql.metadata.execution.MethodInvoker;
+import io.leangen.graphql.metadata.execution.*;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.lang.reflect.AnnotatedType;
 import java.lang.reflect.Method;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.function.Supplier;
 
 public class DefaultMethodInvokerFactory implements MethodInvokerFactory {
+    private static final Logger log = LoggerFactory.getLogger(DefaultMethodInvokerFactory.class);
+    private final AtomicBoolean USE_SET_ACCESSIBLE = new AtomicBoolean(true);
+    private final AtomicBoolean USE_LAMBDA_FACTORY = new AtomicBoolean(true);
 
     @Override
     public Executable<Method> create(Supplier<Object> targetSupplier, Method resolverMethod, AnnotatedType enclosingType, Class<?> exposedType) {
-        return targetSupplier == null ? new MethodInvoker(resolverMethod, enclosingType) : new FixedMethodInvoker(targetSupplier, resolverMethod, enclosingType);
+        try {
+            if (USE_LAMBDA_FACTORY.get()) {
+                return targetSupplier == null ? new LambdaInvoker(resolverMethod, enclosingType,
+                        USE_SET_ACCESSIBLE.get()) : new FixedLambdaInvoker(targetSupplier, resolverMethod, enclosingType,
+                        USE_SET_ACCESSIBLE.get());
+            }
+        } catch (Exception e) {
+            log.warn("Lambda Invokers could not be used for {} because {}", resolverMethod, e.toString());
+        }
+
+        return targetSupplier == null ? new MethodInvoker(resolverMethod, enclosingType) : new FixedMethodInvoker(targetSupplier,
+                resolverMethod, enclosingType);
     }
 }