java.lang.invoke.MethodHandle类的使用及代码示例

x33g5p2x  于2022-01-24 转载在 其他  
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本文整理了Java中java.lang.invoke.MethodHandle类的一些代码示例，展示了MethodHandle类的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。MethodHandle类的具体详情如下：
包路径：java.lang.invoke.MethodHandle
类名称：MethodHandle

MethodHandle介绍

[英]Stub class needed to satisfy Java 8 compilers when compiling lambdas.
[中]编译lambda时，存根类需要满足Java 8编译器的要求。

代码示例

代码示例来源：origin: apache/kafka

@Override
  public Checksum create() {
    try {
      return (Checksum) CONSTRUCTOR.invoke();
    } catch (Throwable throwable) {
      // Should never happen
      throw new RuntimeException(throwable);
    }
  }
}

代码示例来源：origin: apache/kafka

private static MethodHandle unmapJava9(MethodHandles.Lookup lookup) throws ReflectiveOperationException {
  Class<?> unsafeClass = Class.forName("sun.misc.Unsafe");
  MethodHandle unmapper = lookup.findVirtual(unsafeClass, "invokeCleaner",
      methodType(void.class, ByteBuffer.class));
  Field f = unsafeClass.getDeclaredField("theUnsafe");
  f.setAccessible(true);
  Object theUnsafe = f.get(null);
  return unmapper.bindTo(theUnsafe);
}

代码示例来源：origin: apache/kafka

public static void unmap(String resourceDescription, MappedByteBuffer buffer) throws IOException {
  if (!buffer.isDirect())
    throw new IllegalArgumentException("Unmapping only works with direct buffers");
  if (UNMAP == null)
    throw UNMAP_NOT_SUPPORTED_EXCEPTION;
  try {
    UNMAP.invokeExact((ByteBuffer) buffer);
  } catch (Throwable throwable) {
    throw new IOException("Unable to unmap the mapped buffer: " + resourceDescription, throwable);
  }
}

代码示例来源：origin: square/retrofit

@Override Object invokeDefaultMethod(Method method, Class<?> declaringClass, Object object,
  @Nullable Object... args) throws Throwable {
 // Because the service interface might not be public, we need to use a MethodHandle lookup
 // that ignores the visibility of the declaringClass.
 Constructor<Lookup> constructor = Lookup.class.getDeclaredConstructor(Class.class, int.class);
 constructor.setAccessible(true);
 return constructor.newInstance(declaringClass, -1 /* trusted */)
   .unreflectSpecial(method, declaringClass)
   .bindTo(object)
   .invokeWithArguments(args);
}

代码示例来源：origin: org.objenesis/objenesis

@Override
 Class<?> defineClass(String className, byte[] b, int off, int len, Class<?> neighbor, ClassLoader loader, ProtectionDomain protectionDomain) {
   try {
    Object module = getModule.invokeWithArguments(DefineClassHelper.class);
    Object neighborModule = getModule.invokeWithArguments(neighbor);
    addReads.invokeWithArguments(module, neighborModule);
    MethodHandles.Lookup prvlookup = (MethodHandles.Lookup) privateLookupIn.invokeExact(neighbor, lookup);
    return (Class<?>) defineClass.invokeExact(prvlookup, b);
   } catch (Throwable e) {
    throw new ObjenesisException(neighbor.getName() + " has no permission to define the class", e);
   }
 }
}

代码示例来源：origin: prestodb/presto

@Override
public ScalarFunctionImplementation specialize(BoundVariables boundVariables, int arity, TypeManager typeManager, FunctionRegistry functionRegistry)
{
  List<Type> types = this.typeParameters.stream().map(boundVariables::getTypeVariable).collect(toImmutableList());
  List<ArgumentProperty> argumentProperties = nCopies(types.size(), valueTypeArgumentProperty(RETURN_NULL_ON_NULL));
  List<Class<?>> javaArgumentTypes = nCopies(types.size(), Block.class);
  MethodHandle methodHandle = METHOD_HANDLE.bindTo(types).asVarargsCollector(Block[].class).asType(methodType(Block.class, javaArgumentTypes));
  return new ScalarFunctionImplementation(false, argumentProperties, methodHandle, isDeterministic());
}

代码示例来源：origin: prestodb/presto

private static MethodHandle bindInstanceFactory(MethodHandle method, ScalarFunctionImplementation implementation)
{
  if (!implementation.getInstanceFactory().isPresent()) {
    return method;
  }
  try {
    return method.bindTo(implementation.getInstanceFactory().get().invoke());
  }
  catch (Throwable throwable) {
    throw propagate(throwable);
  }
}

代码示例来源：origin: robolectric/robolectric

private static MethodHandle cleanStackTraces(MethodHandle mh) {
  MethodType type = EXCEPTION_HANDLER.type().changeReturnType(mh.type().returnType());
  return catchException(mh, Throwable.class, EXCEPTION_HANDLER.asType(type));
 }
}

代码示例来源：origin: prestodb/presto

@Override
protected Object visitArithmeticUnary(ArithmeticUnaryExpression node, Object context)
{
  Object value = process(node.getValue(), context);
  if (value == null) {
    return null;
  }
  if (value instanceof Expression) {
    return new ArithmeticUnaryExpression(node.getSign(), toExpression(value, type(node.getValue())));
  }
  switch (node.getSign()) {
    case PLUS:
      return value;
    case MINUS:
      Signature operatorSignature = metadata.getFunctionRegistry().resolveOperator(OperatorType.NEGATION, types(node.getValue()));
      MethodHandle handle = metadata.getFunctionRegistry().getScalarFunctionImplementation(operatorSignature).getMethodHandle();
      if (handle.type().parameterCount() > 0 && handle.type().parameterType(0) == ConnectorSession.class) {
        handle = handle.bindTo(session);
      }
      try {
        return handle.invokeWithArguments(value);
      }
      catch (Throwable throwable) {
        throwIfInstanceOf(throwable, RuntimeException.class);
        throwIfInstanceOf(throwable, Error.class);
        throw new RuntimeException(throwable.getMessage(), throwable);
      }
  }
  throw new UnsupportedOperationException("Unsupported unary operator: " + node.getSign());
}

代码示例来源：origin: prestodb/presto

@Override
public ScalarFunctionImplementation specialize(BoundVariables boundVariables, int arity, TypeManager typeManager, FunctionRegistry functionRegistry)
{
  Type inputType = boundVariables.getTypeVariable("T");
  Type intermediateType = boundVariables.getTypeVariable("S");
  Type outputType = boundVariables.getTypeVariable("R");
  MethodHandle methodHandle = METHOD_HANDLE.bindTo(inputType);
  return new ScalarFunctionImplementation(
      true,
      ImmutableList.of(
          valueTypeArgumentProperty(RETURN_NULL_ON_NULL),
          valueTypeArgumentProperty(USE_BOXED_TYPE),
          functionTypeArgumentProperty(BinaryFunctionInterface.class),
          functionTypeArgumentProperty(UnaryFunctionInterface.class)),
      methodHandle.asType(
          methodHandle.type()
              .changeParameterType(1, Primitives.wrap(intermediateType.getJavaType()))
              .changeReturnType(Primitives.wrap(outputType.getJavaType()))),
      isDeterministic());
}

代码示例来源：origin: org.codehaus.groovy/groovy

/**
 * Core method for indy method selection using runtime types.
 */
public static Object selectMethod(MutableCallSite callSite, Class sender, String methodName, int callID, Boolean safeNavigation, Boolean thisCall, Boolean spreadCall, Object dummyReceiver, Object[] arguments) throws Throwable {
  Selector selector = Selector.getSelector(callSite, sender, methodName, callID, safeNavigation, thisCall, spreadCall, arguments); 
  selector.setCallSiteTarget();
  MethodHandle call = selector.handle.asSpreader(Object[].class, arguments.length);
  call = call.asType(MethodType.methodType(Object.class,Object[].class));
  return call.invokeExact(arguments);
}

代码示例来源：origin: org.codehaus.groovy/groovy

@Override
  public Object invokeHandle(Object handle, Object[] args) throws Throwable {
    MethodHandle mh = (MethodHandle) handle;
    return mh.invokeWithArguments(args);
  }
}

代码示例来源：origin: robolectric/robolectric

private static MethodHandle bindWithFallback(RoboCallSite site, MethodHandle mh,
  MethodHandle fallback) {
 SwitchPoint switchPoint = getInvalidator(site.getTheClass());
 MethodType type = site.type();
 MethodHandle boundFallback = foldArguments(exactInvoker(type), fallback.bindTo(site));
 try {
  mh = switchPoint.guardWithTest(mh.asType(type), boundFallback);
 } catch (WrongMethodTypeException e) {
  if (site instanceof MethodCallSite) {
   MethodCallSite methodCallSite = (MethodCallSite) site;
   throw new RuntimeException("failed to bind " + methodCallSite.thisType() + "."
     + methodCallSite.getName(), e);
  } else {
   throw e;
  }
 }
 site.setTarget(mh);
 return mh;
}

代码示例来源：origin: prestodb/presto

public Binding bind(MethodHandle method)
{
  long bindingId = nextId++;
  Binding binding = new Binding(bindingId, method.type());
  bindings.put(bindingId, method);
  return binding;
}

代码示例来源：origin: org.apache.lucene/lucene-core

/**
 * Returns a correctly typed {@link MethodHandle} for the no-arg ctor of the given class.
 */
static final MethodHandle findAttributeImplCtor(Class<? extends AttributeImpl> clazz) {
 try {
  return lookup.findConstructor(clazz, NO_ARG_CTOR).asType(NO_ARG_RETURNING_ATTRIBUTEIMPL);
 } catch (NoSuchMethodException | IllegalAccessException e) {
  throw new IllegalArgumentException("Cannot lookup accessible no-arg constructor for: " + clazz.getName(), e);
 }
}

代码示例来源：origin: prestodb/presto

public Procedure(String schema, String name, List<Argument> arguments, MethodHandle methodHandle)
{
  this.schema = checkNotNullOrEmpty(schema, "schema").toLowerCase(ENGLISH);
  this.name = checkNotNullOrEmpty(name, "name").toLowerCase(ENGLISH);
  this.arguments = unmodifiableList(new ArrayList<>(arguments));
  this.methodHandle = requireNonNull(methodHandle, "methodHandle is null");
  Set<String> names = new HashSet<>();
  for (Argument argument : arguments) {
    checkArgument(names.add(argument.getName()), "Duplicate argument name: " + argument.getName());
  }
  checkArgument(!methodHandle.isVarargsCollector(), "Method must have fixed arity");
  checkArgument(methodHandle.type().returnType() == void.class, "Method must return void");
  long parameterCount = methodHandle.type().parameterList().stream()
      .filter(type -> !ConnectorSession.class.isAssignableFrom(type))
      .count();
  checkArgument(parameterCount == arguments.size(), "Method parameter count must match arguments");
}

代码示例来源：origin: org.codehaus.groovy/groovy

/**
 * Sets a handle to call {@link GroovyInterceptable#invokeMethod(String, Object)}
 */
public boolean setInterceptor() {
  if (!(this.args[0] instanceof GroovyInterceptable)) return false;
  handle = MethodHandles.insertArguments(INTERCEPTABLE_INVOKER, 1, this.name);
  handle = handle.asCollector(Object[].class, targetType.parameterCount()-1); 
  handle = handle.asType(targetType);
  return true;
}

代码示例来源：origin: baomidou/mybatis-plus

private Object invokeDefaultMethod(Object proxy, Method method, Object[] args)
  throws Throwable {
  final Constructor<MethodHandles.Lookup> constructor = MethodHandles.Lookup.class
    .getDeclaredConstructor(Class.class, int.class);
  if (!constructor.isAccessible()) {
    constructor.setAccessible(true);
  }
  final Class<?> declaringClass = method.getDeclaringClass();
  return constructor
    .newInstance(declaringClass,
      MethodHandles.Lookup.PRIVATE | MethodHandles.Lookup.PROTECTED
        | MethodHandles.Lookup.PACKAGE | MethodHandles.Lookup.PUBLIC)
    .unreflectSpecial(method, declaringClass).bindTo(proxy).invokeWithArguments(args);
}

代码示例来源：origin: prestodb/presto

private MethodHandle getMethodHandle(Method method)
{
  MethodHandle methodHandle = methodHandle(FUNCTION_IMPLEMENTATION_ERROR, method);
  if (!isStatic(method.getModifiers())) {
    // Change type of "this" argument to Object to make sure callers won't have classloader issues
    methodHandle = methodHandle.asType(methodHandle.type().changeParameterType(0, Object.class));
    // Re-arrange the parameters, so that the "this" parameter is after the meta parameters
    int[] permutedIndices = new int[methodHandle.type().parameterCount()];
    permutedIndices[0] = dependencies.size();
    MethodType newType = methodHandle.type().changeParameterType(dependencies.size(), methodHandle.type().parameterType(0));
    for (int i = 0; i < dependencies.size(); i++) {
      permutedIndices[i + 1] = i;
      newType = newType.changeParameterType(i, methodHandle.type().parameterType(i + 1));
    }
    for (int i = dependencies.size() + 1; i < permutedIndices.length; i++) {
      permutedIndices[i] = i;
    }
    methodHandle = permuteArguments(methodHandle, newType, permutedIndices);
  }
  return methodHandle;
}

代码示例来源：origin: oracle/helidon

public T create(Config configNode) {
  List<Object> args = createArguments(configNode);
  try {
    Object obj = handle.invokeWithArguments(args);
    return type.cast(obj);
  } catch (ConfigException ex) {
    throw ex;
  } catch (Throwable throwable) {
    throw new ConfigException("Unable to create '" + type.getName() + "' instance.", throwable);
  }
}

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