Cache MethodHandles in LocalCacheFactory and NodeFactory (#905)

* Cache constructor MethodHandles in factories

Update LocalCacheFactory.java

* Cache constructor MethodHandles in factories

use invokeExact and findClass

* Cache constructor MethodHandles in factories

use var

* Cache BoundedLocalCache and Node factory instances

* Cache LocalCacheFactory and NodeFactory instances

added slow path for our AOT friends

caffeine/src/javaPoet/java/com/github/benmanes/caffeine/cache/Specifications.java

@@ -19,7 +19,7 @@
 import java.lang.invoke.VarHandle;
 import java.lang.ref.Reference;
 import java.lang.ref.ReferenceQueue;
-
+import org.checkerframework.checker.nullness.qual.Nullable;
 import com.squareup.javapoet.ClassName;
 import com.squareup.javapoet.ParameterSpec;
 import com.squareup.javapoet.ParameterizedTypeName;
@@ -82,7 +82,7 @@ public final class Specifications {
   public static final ParameterizedTypeName ASYNC_CACHE_LOADER = ParameterizedTypeName.get(
       ClassName.get(PACKAGE_NAME, "AsyncCacheLoader"), TypeVariableName.get("? super K"), vTypeVar);
   public static final ParameterSpec ASYNC_CACHE_LOADER_PARAM =
-      ParameterSpec.builder(ASYNC_CACHE_LOADER, "cacheLoader").build();
+      ParameterSpec.builder(ASYNC_CACHE_LOADER, "cacheLoader").addAnnotation(Nullable.class).build();
 
   public static final TypeName REMOVAL_LISTENER = ParameterizedTypeName.get(
       ClassName.get(PACKAGE_NAME, "RemovalListener"), kTypeVar, vTypeVar);

caffeine/src/javaPoet/java/com/github/benmanes/caffeine/cache/local/AddConstructor.java

@@ -16,8 +16,11 @@
 package com.github.benmanes.caffeine.cache.local;
 
 import static com.github.benmanes.caffeine.cache.Specifications.ASYNC_CACHE_LOADER_PARAM;
+import static com.github.benmanes.caffeine.cache.Specifications.LOCAL_CACHE_FACTORY;
 import static com.github.benmanes.caffeine.cache.Specifications.BOUNDED_LOCAL_CACHE;
 import static com.github.benmanes.caffeine.cache.Specifications.BUILDER_PARAM;
+import javax.lang.model.element.Modifier;
+import com.squareup.javapoet.FieldSpec;
 
 /**
  * Adds the constructor to the cache.
@@ -44,5 +47,8 @@ protected void execute() {
     } else {
       context.constructor.addStatement("super(builder, cacheLoader, async)");
     }
+    context.cache
+        .addField(FieldSpec.builder(LOCAL_CACHE_FACTORY, "FACTORY", Modifier.STATIC, Modifier.FINAL)
+            .initializer("$N::new", context.className).build());
   }
 }

caffeine/src/javaPoet/java/com/github/benmanes/caffeine/cache/local/LocalCacheContext.java

@@ -32,6 +32,7 @@
  */
 public final class LocalCacheContext {
   public final boolean isFinal;
+  public final String className;
   public final TypeName superClass;
   public final TypeSpec.Builder cache;
   public final MethodSpec.Builder constructor;
@@ -42,6 +43,7 @@ public final class LocalCacheContext {
   public LocalCacheContext(TypeName superClass, String className, boolean isFinal,
       Set<Feature> parentFeatures, Set<Feature> generateFeatures) {
     this.isFinal = isFinal;
+    this.className = className;
     this.superClass = superClass;
     this.suppressedWarnings = new TreeSet<>();
     this.cache = TypeSpec.classBuilder(className);

caffeine/src/jmh/java/com/github/benmanes/caffeine/FactoryBenchmark.java

@@ -15,14 +15,15 @@
  */
 package com.github.benmanes.caffeine;
 
+import java.lang.invoke.LambdaMetafactory;
 import java.lang.invoke.MethodHandle;
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.MethodType;
 import java.lang.reflect.Constructor;
-
 import org.openjdk.jmh.annotations.Benchmark;
 import org.openjdk.jmh.annotations.Scope;
 import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.infra.Blackhole;
 
 /**
  * @author ben.manes@gmail.com (Ben Manes)
@@ -34,35 +35,46 @@ public class FactoryBenchmark {
   private final MethodHandleFactory methodHandleFactory = new MethodHandleFactory();
 
   @Benchmark
-  public Alpha direct() {
-    return new Alpha();
+  public void direct(Blackhole blackhole) {
+    blackhole.consume(new Alpha());
   }
 
   @Benchmark
-  public Alpha methodHandle_invoke() {
-    return methodHandleFactory.invoke();
+  public void methodHandle_invoke(Blackhole blackhole) {
+    blackhole.consume(methodHandleFactory.invoke());
   }
 
   @Benchmark
-  public Alpha methodHandle_invokeExact() {
-    return methodHandleFactory.invokeExact();
+  public void methodHandle_invokeExact(Blackhole blackhole) {
+    blackhole.consume(methodHandleFactory.invokeExact());
   }
 
   @Benchmark
-  public Alpha reflection() {
-    return reflectionFactory.newInstance();
+  public void methodHandle_lambda(Blackhole blackhole) {
+    blackhole.consume(methodHandleFactory.lambda());
+  }
+
+  @Benchmark
+  public void reflection(Blackhole blackhole) {
+    blackhole.consume(reflectionFactory.newInstance());
   }
 
   static final class MethodHandleFactory {
     private static final MethodHandles.Lookup LOOKUP = MethodHandles.lookup();
     private static final MethodType METHOD_TYPE = MethodType.methodType(void.class);
 
     private final MethodHandle methodHandle;
+    private final AlphaConstructor lambda;
 
     MethodHandleFactory() {
       try {
         methodHandle = LOOKUP.findConstructor(Alpha.class, METHOD_TYPE);
-      } catch (NoSuchMethodException | IllegalAccessException e) {
+        lambda =
+            (AlphaConstructor) LambdaMetafactory
+                .metafactory(LOOKUP, "construct", MethodType.methodType(AlphaConstructor.class),
+                    methodHandle.type(), methodHandle, methodHandle.type())
+                .getTarget().invokeExact();
+      } catch (Throwable e) {
         throw new RuntimeException(e);
       }
     }
@@ -82,6 +94,10 @@ Alpha invokeExact() {
         throw new RuntimeException(e);
       }
     }
+
+    Alpha lambda() {
+      return lambda.construct();
+    }
   }
 
   static final class ReflectionFactory {
@@ -107,4 +123,8 @@ Alpha newInstance() {
   static final class Alpha {
     public Alpha() {}
   }
+
+  private interface AlphaConstructor {
+    Alpha construct();
+  }
 }

caffeine/src/main/java/com/github/benmanes/caffeine/cache/LocalCacheFactory.java

@@ -15,23 +15,25 @@
  */
 package com.github.benmanes.caffeine.cache;
 
-import java.lang.invoke.MethodHandle;
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.MethodType;
-
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 /**
  * A factory for caches optimized for a particular configuration.
  *
  * @author ben.manes@gmail.com (Ben Manes)
  */
-final class LocalCacheFactory {
-  private static final MethodHandles.Lookup LOOKUP = MethodHandles.lookup();
-  private static final MethodType FACTORY = MethodType.methodType(
+interface LocalCacheFactory {
+  MethodHandles.Lookup LOOKUP = MethodHandles.lookup();
+  MethodType FACTORY = MethodType.methodType(
       void.class, Caffeine.class, AsyncCacheLoader.class, boolean.class);
+  Map<String, LocalCacheFactory> FACTORIES = new ConcurrentHashMap<>();
 
-  private LocalCacheFactory() {}
+  <K, V> BoundedLocalCache<K, V> newInstance(Caffeine<K, V> builder,
+      @Nullable AsyncCacheLoader<? super K, V> cacheLoader, boolean async);
 
   /** Returns a cache optimized for this configuration. */
   static <K, V> BoundedLocalCache<K, V> newBoundedLocalCache(Caffeine<K, V> builder,
@@ -41,7 +43,7 @@ static <K, V> BoundedLocalCache<K, V> newBoundedLocalCache(Caffeine<K, V> builde
   }
 
   static String getClassName(Caffeine<?, ?> builder) {
-    var className = new StringBuilder(LocalCacheFactory.class.getPackageName()).append('.');
+    var className = new StringBuilder();
     if (builder.isStrongKeys()) {
       className.append('S');
     } else {
@@ -80,10 +82,38 @@ static String getClassName(Caffeine<?, ?> builder) {
 
   static <K, V> BoundedLocalCache<K, V> loadFactory(Caffeine<K, V> builder,
       @Nullable AsyncCacheLoader<? super K, V> cacheLoader, boolean async, String className) {
+    var factory = FACTORIES.get(className);
+    if (factory == null) {
+      factory = FACTORIES.computeIfAbsent(className, LocalCacheFactory::newFactory);
+    }
+    return factory.newInstance(builder, cacheLoader, async);
+  }
+
+  static LocalCacheFactory newFactory(String className) {
     try {
-      Class<?> clazz = Class.forName(className);
-      MethodHandle handle = LOOKUP.findConstructor(clazz, FACTORY);
-      return (BoundedLocalCache<K, V>) handle.invoke(builder, cacheLoader, async);
+      var clazz = LOOKUP.findClass(LocalCacheFactory.class.getPackageName() + "." + className);
+      try {
+        // Fast path
+        return (LocalCacheFactory) LOOKUP
+            .findStaticVarHandle(clazz, "FACTORY", LocalCacheFactory.class).get();
+      } catch (NoSuchFieldException e) {
+        // Slow path when native hints are missing the field, but may have the constructor.
+        var constructor = LOOKUP.findConstructor(clazz, FACTORY);
+        var methodHandle =
+            constructor.asType(constructor.type().changeReturnType(BoundedLocalCache.class));
+        return new LocalCacheFactory() {
+          @Override
+          public <K, V> BoundedLocalCache<K, V> newInstance(Caffeine<K, V> builder,
+              @Nullable AsyncCacheLoader<? super K, V> cacheLoader, boolean async) {
+            try {
+              return (BoundedLocalCache<K, V>) methodHandle.invokeExact(builder, cacheLoader,
+                  async);
+            } catch (Throwable t) {
+              throw new IllegalStateException(className, t);
+            }
+          }
+        };
+      }
     } catch (RuntimeException | Error e) {
       throw e;
     } catch (Throwable t) {

caffeine/src/main/java/com/github/benmanes/caffeine/cache/NodeFactory.java

@@ -15,10 +15,11 @@
  */
 package com.github.benmanes.caffeine.cache;
 
-import java.lang.invoke.MethodHandle;
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.MethodType;
 import java.lang.ref.ReferenceQueue;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
 import com.github.benmanes.caffeine.cache.References.LookupKeyReference;
 import com.github.benmanes.caffeine.cache.References.WeakKeyReference;
@@ -31,6 +32,7 @@
 interface NodeFactory<K, V> {
   MethodType FACTORY = MethodType.methodType(void.class);
   MethodHandles.Lookup LOOKUP = MethodHandles.lookup();
+  Map<String, NodeFactory<Object, Object>> FACTORIES = new ConcurrentHashMap<>();
 
   RetiredStrongKey RETIRED_STRONG_KEY = new RetiredStrongKey();
   RetiredWeakKey RETIRED_WEAK_KEY = new RetiredWeakKey();
@@ -87,7 +89,7 @@ static <K, V> NodeFactory<K, V> newFactory(Caffeine<K, V> builder, boolean isAsy
   }
 
   static String getClassName(Caffeine<?, ?> builder, boolean isAsync) {
-    var className = new StringBuilder(Node.class.getPackageName()).append('.');
+    var className = new StringBuilder();
     if (builder.isStrongKeys()) {
       className.append('P');
     } else {
@@ -131,11 +133,21 @@ static String getClassName(Caffeine<?, ?> builder, boolean isAsync) {
     return className.toString();
   }
 
+  @SuppressWarnings("unchecked")
   static <K, V> NodeFactory<K, V> loadFactory(String className) {
+    var factory = FACTORIES.get(className);
+    if (factory == null) {
+      factory = FACTORIES.computeIfAbsent(className, NodeFactory::newFactory);
+    }
+    return (NodeFactory<K, V>) factory;
+  }
+
+  static NodeFactory<Object, Object> newFactory(String className) {
     try {
-      Class<?> clazz = Class.forName(className);
-      MethodHandle handle = LOOKUP.findConstructor(clazz, FACTORY);
-      return (NodeFactory<K, V>) handle.invoke();
+      var clazz = LOOKUP.findClass(Node.class.getPackageName() + "." + className);
+      var constructor = LOOKUP.findConstructor(clazz, FACTORY);
+      return (NodeFactory<Object, Object>) constructor
+          .asType(constructor.type().changeReturnType(NodeFactory.class)).invokeExact();
     } catch (RuntimeException | Error e) {
       throw e;
     } catch (Throwable t) {

caffeine/src/test/java/com/github/benmanes/caffeine/cache/BoundedLocalCacheTest.java

@@ -50,7 +50,6 @@
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.not;
 import static org.hamcrest.Matchers.nullValue;
-import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertThrows;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyLong;