!960 [enhancement] 使LambdaFactory.build支持构造器

Merge pull request !960 from 阿超/v6-dev

hutool-core/src/main/java/cn/hutool/core/lang/func/LambdaFactory.java

@@ -7,9 +7,12 @@ import cn.hutool.core.lang.mutable.MutableEntry;
 import cn.hutool.core.map.WeakConcurrentMap;
 import cn.hutool.core.reflect.LookupFactory;
 import cn.hutool.core.reflect.MethodUtil;
+import cn.hutool.core.reflect.ReflectUtil;
 
 import java.io.Serializable;
 import java.lang.invoke.*;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Executable;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.util.Arrays;
@@ -31,7 +34,7 @@ public class LambdaFactory {
 		throw new IllegalAccessException();
 	}
 
-	private static final Map<MutableEntry<Class<?>, Method>, Object> CACHE = new WeakConcurrentMap<>();
+	private static final Map<MutableEntry<Class<?>, Executable>, Object> CACHE = new WeakConcurrentMap<>();
 
 	/**
 	 * 构建Lambda
@@ -61,30 +64,37 @@ public class LambdaFactory {
 	 * 构建Lambda
 	 *
 	 * @param functionInterfaceType 接受Lambda的函数式接口类型
-	 * @param method                方法对象
+	 * @param executable                方法对象，支持构造器
+	 * @param <F>                   Function类型
 	 * @return 接受Lambda的函数式接口对象
-	 * @param <F> Function类型
 	 */
 	@SuppressWarnings("unchecked")
-	public static <F> F build(final Class<F> functionInterfaceType, final Method method) {
+	public static <F> F build(final Class<F> functionInterfaceType, final Executable executable) {
 		Assert.notNull(functionInterfaceType);
-		Assert.notNull(method);
+		Assert.notNull(executable);
-		final MutableEntry<Class<?>, Method> cacheKey = new MutableEntry<>(functionInterfaceType, method);
+		final MutableEntry<Class<?>, Executable> cacheKey = new MutableEntry<>(functionInterfaceType, executable);
 		return (F) CACHE.computeIfAbsent(cacheKey, key -> {
 			final List<Method> abstractMethods = Arrays.stream(functionInterfaceType.getMethods())
 					.filter(m -> Modifier.isAbstract(m.getModifiers()))
 					.collect(Collectors.toList());
 			Assert.equals(abstractMethods.size(), 1, "不支持非函数式接口");
-			if (!method.isAccessible()) {
+			ReflectUtil.setAccessible(executable);
-				method.setAccessible(true);
-			}
 			final Method invokeMethod = abstractMethods.get(0);
-			final MethodHandles.Lookup caller = LookupFactory.lookup(method.getDeclaringClass());
+			final MethodHandles.Lookup caller = LookupFactory.lookup(executable.getDeclaringClass());
 			final String invokeName = invokeMethod.getName();
 			final MethodType invokedType = methodType(functionInterfaceType);
 			final MethodType samMethodType = methodType(invokeMethod.getReturnType(), invokeMethod.getParameterTypes());
-			final MethodHandle implMethod = Opt.ofTry(() -> caller.unreflect(method)).get();
+			final MethodHandle implMethod;
-			final MethodType insMethodType = methodType(method.getReturnType(), method.getDeclaringClass(), method.getParameterTypes());
+			final MethodType instantiatedMethodType;
+			if (executable instanceof Method) {
+				final Method method = (Method) executable;
+				implMethod = ((SerSupplier<MethodHandle>) () -> MethodHandles.lookup().unreflect(method)).get();
+				instantiatedMethodType = MethodType.methodType(method.getReturnType(), method.getDeclaringClass(), method.getParameterTypes());
+			} else {
+				final Constructor<?> constructor = (Constructor<?>) executable;
+				implMethod = ((SerSupplier<MethodHandle>) () -> MethodHandles.lookup().unreflectConstructor(constructor)).get();
+				instantiatedMethodType = MethodType.methodType(constructor.getDeclaringClass(), constructor.getParameterTypes());
+			}
 			final boolean isSerializable = Serializable.class.isAssignableFrom(functionInterfaceType);
 			try {
 				final CallSite callSite = isSerializable ?
@@ -94,7 +104,7 @@ public class LambdaFactory {
 								invokedType,
 								samMethodType,
 								implMethod,
-								insMethodType,
+								instantiatedMethodType,
 								FLAG_SERIALIZABLE
 						) :
 						LambdaMetafactory.metafactory(
@@ -103,7 +113,7 @@ public class LambdaFactory {
 								invokedType,
 								samMethodType,
 								implMethod,
-								insMethodType
+								instantiatedMethodType
 						);
 				//noinspection unchecked
 				return (F) callSite.getTarget().invoke();

hutool-core/src/test/java/cn/hutool/core/lang/func/LambdaFactoryTest.java

@@ -12,11 +12,8 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.Parameterized;
 
-import java.lang.invoke.LambdaConversionException;
+import java.lang.invoke.*;
-import java.lang.invoke.MethodHandle;
+import java.lang.reflect.Constructor;
-import java.lang.invoke.MethodHandleProxies;
-import java.lang.invoke.MethodHandles;
-import java.lang.invoke.MethodType;
 import java.lang.reflect.Method;
 import java.util.Arrays;
 import java.util.Collection;
@@ -24,6 +21,7 @@ import java.util.Comparator;
 import java.util.concurrent.TimeUnit;
 import java.util.function.BiConsumer;
 import java.util.function.Function;
+import java.util.function.Supplier;
 
 /**
  * @author nasodaengineer
@@ -160,6 +158,15 @@ public class LambdaFactoryTest {
 			loop(count, tasks);
 		}
 
+		@Test
+		public void testConstructor() {
+			Constructor<Something> constructor = ((SerSupplier<Constructor<Something>>) Something.class::getConstructor).get();
+			Supplier<Something> constructorLambda = LambdaFactory.build(Supplier.class, constructor);
+			// constructorLambda can be cache or transfer
+			Something something = constructorLambda.get();
+			Assert.assertEquals(Something.class, something.getClass());
+		}
+
 		/**
 		 * <p>hardCode   运行1次耗时 7600 NANOSECONDS
 		 * <p>lambda     运行1次耗时 12400 NANOSECONDS