Custom lookup for reflective schemas

This commit updates `BeanTableSchema` and `ImmutableTableSchema` to allow
customers to provide their own instance of `MethodHandle.Lookup`.

This is a necessary feature for situations where either of these schemas
are used in an application where the item classes and the SDK classes
are loaded by different classloaders. Since these schemas work by
reflectively scanning the item class to find the attributes' getters and
setters (or builder for immutable classes), the enhanced client makes
use of a LambdaMetaFactory to construct lambdas that directly call these
methods to avoid reflection when mapping to and from a
`AttributeValue`s. At least as of Java 21, the way that lambdas are
constructed (all lambdas, not just the ones created by the enhanced
client), is they are made internal classes of the "caller" class, i.e.
the class that defined it. The calling class is identified by the class
that created the `Lookup` object. This means that when using the default
`Lookup` created `LambdaToMethodBridgeBuilder`, all of these lambdas are
inner classes of of `LambdaToMethodBridgeBuilder`. This is an issue when
the item class is from a different classloader (or module) because when
the lambda attempts to reference the item class (e.g. to call a getter),
it's `ClassLoader` will throw a `ClassNotFoundException` because because
it's not a class that it knows about.

By allowing the customer to provide a `Lookup` object, they can
guarantee that the the `Lookup` has visibility and access to the item
classes.

.changes/next-release/feature-DynamoDBEnhancedClient-f39cb99.json

@@ -0,0 +1,6 @@
+{
+    "type": "feature",
+    "category": "DynamoDB Enhanced Client",
+    "contributor": "",
+    "description": "Add ability to provide a custom `MethodHandles.Lookup` object when using either `BeanTableSchema` or `ImmutableTableSchema`. By setting a custom `MethodHandles.Lookup` it allows these schemas to be used in applications where the item class and the SDK are loaded by different `ClassLoader`s."
+}

services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/internal/mapper/BeanAttributeGetter.java

@@ -15,6 +15,7 @@
 
 package software.amazon.awssdk.enhanced.dynamodb.internal.mapper;
 
+import java.lang.invoke.MethodHandles;
 import java.lang.reflect.Method;
 import java.util.function.Function;
 import software.amazon.awssdk.annotations.SdkInternalApi;
@@ -24,12 +25,14 @@
 @SdkInternalApi
 @SuppressWarnings("unchecked")
 public interface BeanAttributeGetter<BeanT, GetterT> extends Function<BeanT, GetterT> {
-    static <BeanT, GetterT> BeanAttributeGetter<BeanT, GetterT> create(Class<BeanT> beanClass, Method getter) {
+    static <BeanT, GetterT> BeanAttributeGetter<BeanT, GetterT> create(Class<BeanT> beanClass, Method getter,
+                                                                       MethodHandles.Lookup lookup) {
         Validate.isTrue(getter.getParameterCount() == 0,
                         "%s.%s has parameters, despite being named like a getter.",
                         beanClass, getter.getName());
 
         return LambdaToMethodBridgeBuilder.create(BeanAttributeGetter.class)
+                                          .lookup(lookup)
                                           .lambdaMethodName("apply")
                                           .runtimeLambdaSignature(Object.class, Object.class)
                                           .compileTimeLambdaSignature(getter.getReturnType(), beanClass)

services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/internal/mapper/BeanAttributeSetter.java

@@ -15,6 +15,7 @@
 
 package software.amazon.awssdk.enhanced.dynamodb.internal.mapper;
 
+import java.lang.invoke.MethodHandles;
 import java.lang.reflect.Method;
 import java.util.function.BiConsumer;
 import software.amazon.awssdk.annotations.SdkInternalApi;
@@ -25,7 +26,9 @@
 @SdkInternalApi
 public interface BeanAttributeSetter<BeanT, GetterT> extends BiConsumer<BeanT, GetterT> {
     @SuppressWarnings("unchecked")
-    static <BeanT, SetterT> BeanAttributeSetter<BeanT, SetterT> create(Class<BeanT> beanClass, Method setter) {
+    static <BeanT, SetterT> BeanAttributeSetter<BeanT, SetterT> create(Class<BeanT> beanClass,
+                                                                       Method setter,
+                                                                       MethodHandles.Lookup lookup) {
         Validate.isTrue(setter.getParameterCount() == 1,
                         "%s.%s doesn't have just 1 parameter, despite being named like a setter.",
                         beanClass, setter.getName());
@@ -34,6 +37,7 @@ static <BeanT, SetterT> BeanAttributeSetter<BeanT, SetterT> create(Class<BeanT>
         Class<?> boxedInputClass = ReflectionUtils.getWrappedClass(setterInputClass);
 
         return LambdaToMethodBridgeBuilder.create(BeanAttributeSetter.class)
+                                          .lookup(lookup)
                                           .lambdaMethodName("accept")
                                           .runtimeLambdaSignature(void.class, Object.class, Object.class)
                                           .compileTimeLambdaSignature(void.class, beanClass, boxedInputClass)

services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/internal/mapper/LambdaToMethodBridgeBuilder.java

@@ -28,9 +28,10 @@
 
 @SdkInternalApi
 public class LambdaToMethodBridgeBuilder<T> {
-    private static final MethodHandles.Lookup LOOKUP = MethodHandles.lookup();
+    private static final MethodHandles.Lookup SELF_LOOKUP = MethodHandles.lookup();
 
     private final Class<T> lambdaType;
+    private MethodHandles.Lookup lookup;
     private String lambdaMethodName;
     private Class<?> postEraseLambdaReturnType;
     private Class<?>[] postEraseLambdaParameters;
@@ -73,14 +74,20 @@ public LambdaToMethodBridgeBuilder<T> targetMethod(Constructor<?> method) {
         return this;
     }
 
+    public LambdaToMethodBridgeBuilder<T> lookup(MethodHandles.Lookup lookup) {
+        this.lookup = lookup;
+        return this;
+    }
+
     public T build() {
+        MethodHandles.Lookup metaFactoryLookup = resolveLookup();
         try {
             MethodHandle targetMethodHandle = targetMethod.map(
-                m -> invokeSafely(() -> LOOKUP.unreflect(m)),
-                c -> invokeSafely(() -> LOOKUP.unreflectConstructor(c)));
+                m -> invokeSafely(() -> metaFactoryLookup.unreflect(m)),
+                c -> invokeSafely(() -> metaFactoryLookup.unreflectConstructor(c)));
 
             return lambdaType.cast(
-                LambdaMetafactory.metafactory(LOOKUP,
+                LambdaMetafactory.metafactory(metaFactoryLookup,
                                               lambdaMethodName,
                                               MethodType.methodType(lambdaType),
                                               MethodType.methodType(postEraseLambdaReturnType, postEraseLambdaParameters),
@@ -92,4 +99,12 @@ public T build() {
             throw new IllegalArgumentException("Failed to generate method handle.", e);
         }
     }
+
+    private MethodHandles.Lookup resolveLookup() {
+        if (lookup != null) {
+            return lookup;
+        }
+
+        return SELF_LOOKUP;
+    }
 }

services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/internal/mapper/ObjectConstructor.java

@@ -15,6 +15,7 @@
 
 package software.amazon.awssdk.enhanced.dynamodb.internal.mapper;
 
+import java.lang.invoke.MethodHandles;
 import java.lang.reflect.Constructor;
 import java.util.function.Supplier;
 import software.amazon.awssdk.annotations.SdkInternalApi;
@@ -24,12 +25,15 @@
 @SdkInternalApi
 @SuppressWarnings("unchecked")
 public interface ObjectConstructor<BeanT> extends Supplier<BeanT> {
-    static <BeanT> ObjectConstructor<BeanT> create(Class<BeanT> beanClass, Constructor<BeanT> noArgsConstructor) {
+    static <BeanT> ObjectConstructor<BeanT> create(Class<BeanT> beanClass, Constructor<BeanT> noArgsConstructor,
+                                                   MethodHandles.Lookup lookup) {
+
         Validate.isTrue(noArgsConstructor.getParameterCount() == 0,
                         "%s has no default constructor.",
                         beanClass);
 
         return LambdaToMethodBridgeBuilder.create(ObjectConstructor.class)
+                                          .lookup(lookup)
                                           .lambdaMethodName("get")
                                           .runtimeLambdaSignature(Object.class)
                                           .compileTimeLambdaSignature(beanClass)

services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/internal/mapper/ObjectGetterMethod.java

@@ -15,6 +15,7 @@
 
 package software.amazon.awssdk.enhanced.dynamodb.internal.mapper;
 
+import java.lang.invoke.MethodHandles;
 import java.lang.reflect.Method;
 import java.util.function.Function;
 import software.amazon.awssdk.annotations.SdkInternalApi;
@@ -23,8 +24,10 @@
 @SdkInternalApi
 @SuppressWarnings("unchecked")
 public interface ObjectGetterMethod<BeanT, GetterT> extends Function<BeanT, GetterT> {
-    static <BeanT, GetterT> ObjectGetterMethod<BeanT, GetterT> create(Class<BeanT> beanClass, Method buildMethod) {
+    static <BeanT, GetterT> ObjectGetterMethod<BeanT, GetterT> create(Class<BeanT> beanClass, Method buildMethod,
+                                                                      MethodHandles.Lookup lookup) {
         return LambdaToMethodBridgeBuilder.create(ObjectGetterMethod.class)
+                                          .lookup(lookup)
                                           .lambdaMethodName("apply")
                                           .runtimeLambdaSignature(Object.class, Object.class)
                                           .compileTimeLambdaSignature(buildMethod.getReturnType(), beanClass)

services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/internal/mapper/StaticGetterMethod.java

@@ -15,6 +15,7 @@
 
 package software.amazon.awssdk.enhanced.dynamodb.internal.mapper;
 
+import java.lang.invoke.MethodHandles;
 import java.lang.reflect.Method;
 import java.util.function.Supplier;
 import software.amazon.awssdk.annotations.SdkInternalApi;
@@ -23,8 +24,10 @@
 @SdkInternalApi
 @SuppressWarnings("unchecked")
 public interface StaticGetterMethod<GetterT> extends Supplier<GetterT> {
-    static <GetterT> StaticGetterMethod<GetterT> create(Method buildMethod) {
+    static <GetterT> StaticGetterMethod<GetterT> create(Method buildMethod,
+                                                        MethodHandles.Lookup lookup) {
         return LambdaToMethodBridgeBuilder.create(StaticGetterMethod.class)
+                                          .lookup(lookup)
                                           .lambdaMethodName("get")
                                           .runtimeLambdaSignature(Object.class)
                                           .compileTimeLambdaSignature(buildMethod.getReturnType())