java.lang.invoke.MethodHandle.type()方法的使用及代码示例

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.type()方法的一些代码示例，展示了MethodHandle.type()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.type()方法的具体详情如下：
包路径：java.lang.invoke.MethodHandle
类名称：MethodHandle
方法名：type

MethodHandle.type介绍

[英]Reports the type of this method handle. Every invocation of this method handle via invokeExact must exactly match this type.
[中]报告此方法句柄的类型。通过invokeExact对此方法句柄的每次调用都必须与此类型完全匹配。

代码示例

代码示例来源：origin: prestodb/presto

  1. public Binding bind(MethodHandle method)
  2. {
  3.   long bindingId = nextId++;
  4.   Binding binding = new Binding(bindingId, method.type());
  5.   bindings.put(bindingId, method);
  6.   return binding;
  7. }

代码示例来源：origin: prestodb/presto

  1. private static void verifyMethodParameterType(MethodHandle method, int index, Class javaType, String sqlTypeDisplayName)
  2. {
  3.   checkArgument(method.type().parameterArray()[index] == javaType,
  4.       "Expected method %s parameter %s type to be %s (%s)",
  5.       method,
  6.       index,
  7.       javaType.getName(),
  8.       sqlTypeDisplayName);
  9. }

代码示例来源：origin: prestodb/presto

  1. private static void verifyExactOutputFunction(MethodHandle method, List<AccumulatorStateDescriptor> stateDescriptors)
  2. {
  3.   if (method == null) {
  4.     return;
  5.   }
  6.   Class<?>[] parameterTypes = method.type().parameterArray();
  7.   checkArgument(parameterTypes.length == stateDescriptors.size() + 1, "Number of arguments for combine function must be exactly one plus than number of states.");
  8.   for (int i = 0; i < stateDescriptors.size(); i++) {
  9.     checkArgument(parameterTypes[i].equals(stateDescriptors.get(i).getStateInterface()), String.format("Type for Parameter index %d is unexpected", i));
  10.   }
  11.   checkArgument(Arrays.stream(parameterTypes).filter(type -> type.equals(BlockBuilder.class)).count() == 1, "Output function must take exactly one BlockBuilder parameter");
  12. }

代码示例来源：origin: prestodb/presto

  1. /**
  2.  * @param f (U, S1, S2, ..., Sm)R
  3.  * @param g (T1, T2, ..., Tn)U
  4.  * @return (T1, T2, ..., Tn, S1, S2, ..., Sm)R
  5.  */
  6. public static MethodHandle compose(MethodHandle f, MethodHandle g)
  7. {
  8.   if (f.type().parameterType(0) != g.type().returnType()) {
  9.     throw new IllegalArgumentException(format("f.parameter(0) != g.return(). f: %s  g: %s", f.type(), g.type()));
  10.   }
  11.   // Semantics: f => f
  12.   // Type: (U, S1, S2, ..., Sn)R => (U, T1, T2, ..., Tm, S1, S2, ..., Sn)R
  13.   MethodHandle fUTS = MethodHandles.dropArguments(f, 1, g.type().parameterList());
  14.   // Semantics: f => fg
  15.   // Type: (U, T1, T2, ..., Tm, S1, S2, ..., Sn)R => (T1, T2, ..., Tm, S1, S2, ..., Sn)R
  16.   return MethodHandles.foldArguments(fUTS, g);
  17. }

代码示例来源：origin: prestodb/presto

  1. /**
  2.  * @param f (U, S1, S2, ..., Sm)R
  3.  * @param g (T1, T2, ..., Tn)U
  4.  * @return (T1, T2, ..., Tn, S1, S2, ..., Sm)R
  5.  */
  6. public static MethodHandle compose(MethodHandle f, MethodHandle g)
  7. {
  8.   if (f.type().parameterType(0) != g.type().returnType()) {
  9.     throw new IllegalArgumentException(format("f.parameter(0) != g.return(). f: %s  g: %s", f.type(), g.type()));
  10.   }
  11.   // Semantics: f => f
  12.   // Type: (U, S1, S2, ..., Sn)R => (U, T1, T2, ..., Tm, S1, S2, ..., Sn)R
  13.   MethodHandle fUTS = MethodHandles.dropArguments(f, 1, g.type().parameterList());
  14.   // Semantics: f => fg
  15.   // Type: (U, T1, T2, ..., Tm, S1, S2, ..., Sn)R => (T1, T2, ..., Tm, S1, S2, ..., Sn)R
  16.   return MethodHandles.foldArguments(fUTS, g);
  17. }

代码示例来源：origin: prestodb/presto

  1. private static void verifyCombineFunction(MethodHandle method, List<Class> lambdaInterfaces, List<AccumulatorStateDescriptor> stateDescriptors)
  2. {
  3.   Class<?>[] parameterTypes = method.type().parameterArray();
  4.   checkArgument(
  5.       parameterTypes.length == stateDescriptors.size() * 2 + lambdaInterfaces.size(),
  6.       "Number of arguments for combine function must be 2 times the size of states plus number of lambda channels.");
  7.   for (int i = 0; i < stateDescriptors.size() * 2; i++) {
  8.     checkArgument(
  9.         parameterTypes[i].equals(stateDescriptors.get(i % stateDescriptors.size()).getStateInterface()),
  10.         String.format("Type for Parameter index %d is unexpected. Arguments for combine function must appear in the order of state1, state2, ..., otherState1, otherState2, ...", i));
  11.   }
  12.   for (int i = 0; i < lambdaInterfaces.size(); i++) {
  13.     verifyMethodParameterType(method, i + stateDescriptors.size() * 2, lambdaInterfaces.get(i), "function");
  14.   }
  15. }

代码示例来源：origin: prestodb/presto

  1. private MethodHandle getMethodHandle(Method method)
  2. {
  3.   MethodHandle methodHandle = methodHandle(FUNCTION_IMPLEMENTATION_ERROR, method);
  4.   if (!isStatic(method.getModifiers())) {
  5.     // Change type of "this" argument to Object to make sure callers won't have classloader issues
  6.     methodHandle = methodHandle.asType(methodHandle.type().changeParameterType(0, Object.class));
  7.     // Re-arrange the parameters, so that the "this" parameter is after the meta parameters
  8.     int[] permutedIndices = new int[methodHandle.type().parameterCount()];
  9.     permutedIndices[0] = dependencies.size();
  10.     MethodType newType = methodHandle.type().changeParameterType(dependencies.size(), methodHandle.type().parameterType(0));
  11.     for (int i = 0; i < dependencies.size(); i++) {
  12.       permutedIndices[i + 1] = i;
  13.       newType = newType.changeParameterType(i, methodHandle.type().parameterType(i + 1));
  14.     }
  15.     for (int i = dependencies.size() + 1; i < permutedIndices.length; i++) {
  16.       permutedIndices[i] = i;
  17.     }
  18.     methodHandle = permuteArguments(methodHandle, newType, permutedIndices);
  19.   }
  20.   return methodHandle;
  21. }

代码示例来源：origin: prestodb/presto

  1. public FieldDefinition getCachedInstance(MethodHandle methodHandle)
  2. {
  3.   FieldDefinition field = classDefinition.declareField(a(PRIVATE, FINAL), "__cachedInstance" + nextId, methodHandle.type().returnType());
  4.   initializers.put(field, methodHandle);
  5.   nextId++;
  6.   return field;
  7. }

代码示例来源：origin: robolectric/robolectric

  1. private static MethodHandle cleanStackTraces(MethodHandle mh) {
  2.   MethodType type = EXCEPTION_HANDLER.type().changeReturnType(mh.type().returnType());
  3.   return catchException(mh, Throwable.class, EXCEPTION_HANDLER.asType(type));
  4.  }
  5. }

代码示例来源：origin: prestodb/presto

  1. public Procedure(String schema, String name, List<Argument> arguments, MethodHandle methodHandle)
  2. {
  3.   this.schema = checkNotNullOrEmpty(schema, "schema").toLowerCase(ENGLISH);
  4.   this.name = checkNotNullOrEmpty(name, "name").toLowerCase(ENGLISH);
  5.   this.arguments = unmodifiableList(new ArrayList<>(arguments));
  6.   this.methodHandle = requireNonNull(methodHandle, "methodHandle is null");
  7.   Set<String> names = new HashSet<>();
  8.   for (Argument argument : arguments) {
  9.     checkArgument(names.add(argument.getName()), "Duplicate argument name: " + argument.getName());
  10.   }
  11.   checkArgument(!methodHandle.isVarargsCollector(), "Method must have fixed arity");
  12.   checkArgument(methodHandle.type().returnType() == void.class, "Method must return void");
  13.   long parameterCount = methodHandle.type().parameterList().stream()
  14.       .filter(type -> !ConnectorSession.class.isAssignableFrom(type))
  15.       .count();
  16.   checkArgument(parameterCount == arguments.size(), "Method parameter count must match arguments");
  17. }

代码示例来源：origin: prestodb/presto

  1. public Procedure(String schema, String name, List<Argument> arguments, MethodHandle methodHandle)
  2. {
  3.   this.schema = checkNotNullOrEmpty(schema, "schema").toLowerCase(ENGLISH);
  4.   this.name = checkNotNullOrEmpty(name, "name").toLowerCase(ENGLISH);
  5.   this.arguments = unmodifiableList(new ArrayList<>(arguments));
  6.   this.methodHandle = requireNonNull(methodHandle, "methodHandle is null");
  7.   Set<String> names = new HashSet<>();
  8.   for (Argument argument : arguments) {
  9.     checkArgument(names.add(argument.getName()), "Duplicate argument name: " + argument.getName());
  10.   }
  11.   checkArgument(!methodHandle.isVarargsCollector(), "Method must have fixed arity");
  12.   checkArgument(methodHandle.type().returnType() == void.class, "Method must return void");
  13.   long parameterCount = methodHandle.type().parameterList().stream()
  14.       .filter(type -> !ConnectorSession.class.isAssignableFrom(type))
  15.       .count();
  16.   checkArgument(parameterCount == arguments.size(), "Method parameter count must match arguments");
  17. }

代码示例来源：origin: prestodb/presto

  1. private void validateProcedure(Procedure procedure)
  2. {
  3.   List<Class<?>> parameters = procedure.getMethodHandle().type().parameterList().stream()
  4.       .filter(type -> !ConnectorSession.class.isAssignableFrom(type))
  5.       .collect(toList());
  6.   for (int i = 0; i < procedure.getArguments().size(); i++) {
  7.     Argument argument = procedure.getArguments().get(i);
  8.     Type type = typeManager.getType(argument.getType());
  9.     Class<?> argumentType = Primitives.unwrap(parameters.get(i));
  10.     Class<?> expectedType = getObjectType(type);
  11.     checkArgument(expectedType.equals(argumentType),
  12.         "Argument '%s' has invalid type %s (expected %s)",
  13.         argument.getName(),
  14.         argumentType.getName(),
  15.         expectedType.getName());
  16.   }
  17. }

代码示例来源：origin: prestodb/presto

  1. private InvokeFunctionBytecodeExpression(
  2.     Scope scope,
  3.     CallSiteBinder binder,
  4.     String name,
  5.     ScalarFunctionImplementation function,
  6.     Optional<BytecodeNode> instance,
  7.     List<BytecodeExpression> parameters)
  8. {
  9.   super(type(Primitives.unwrap(function.getMethodHandle().type().returnType())));
  10.   this.invocation = generateInvocation(
  11.       scope,
  12.       name,
  13.       function,
  14.       instance,
  15.       parameters.stream().map(BytecodeNode.class::cast).collect(toImmutableList()),
  16.       binder);
  17.   this.oneLineDescription = name + "(" + Joiner.on(", ").join(parameters) + ")";
  18. }

代码示例来源：origin: apache/kafka

  1. private static MethodHandle unmapJava7Or8(MethodHandles.Lookup lookup) throws ReflectiveOperationException {
  2.   /* "Compile" a MethodHandle that is roughly equivalent to the following lambda:
  3.    *
  4.    * (ByteBuffer buffer) -> {
  5.    *   sun.misc.Cleaner cleaner = ((java.nio.DirectByteBuffer) byteBuffer).cleaner();
  6.    *   if (nonNull(cleaner))
  7.    *     cleaner.clean();
  8.    *   else
  9.    *     noop(cleaner); // the noop is needed because MethodHandles#guardWithTest always needs both if and else
  10.    * }
  11.    */
  12.   Class<?> directBufferClass = Class.forName("java.nio.DirectByteBuffer");
  13.   Method m = directBufferClass.getMethod("cleaner");
  14.   m.setAccessible(true);
  15.   MethodHandle directBufferCleanerMethod = lookup.unreflect(m);
  16.   Class<?> cleanerClass = directBufferCleanerMethod.type().returnType();
  17.   MethodHandle cleanMethod = lookup.findVirtual(cleanerClass, "clean", methodType(void.class));
  18.   MethodHandle nonNullTest = lookup.findStatic(MappedByteBuffers.class, "nonNull",
  19.       methodType(boolean.class, Object.class)).asType(methodType(boolean.class, cleanerClass));
  20.   MethodHandle noop = dropArguments(constant(Void.class, null).asType(methodType(void.class)), 0, cleanerClass);
  21.   MethodHandle unmapper = filterReturnValue(directBufferCleanerMethod, guardWithTest(nonNullTest, cleanMethod, noop))
  22.       .asType(methodType(void.class, ByteBuffer.class));
  23.   return unmapper;
  24. }

代码示例来源：origin: prestodb/presto

  1. @Override
  2. public ScalarFunctionImplementation specialize(
  3.     BoundVariables boundVariables, int arity, TypeManager typeManager,
  4.     FunctionRegistry functionRegistry)
  5. {
  6.   Type toType = boundVariables.getTypeVariable("E");
  7.   MethodHandle methodHandle = METHOD_HANDLE_NON_NULL.asType(METHOD_HANDLE_NON_NULL.type().changeReturnType(toType.getJavaType()));
  8.   return new ScalarFunctionImplementation(
  9.       false,
  10.       ImmutableList.of(valueTypeArgumentProperty(RETURN_NULL_ON_NULL)),
  11.       methodHandle,
  12.       isDeterministic());
  13. }

代码示例来源：origin: prestodb/presto

  1. @Override
  2. public ScalarFunctionImplementation specialize(BoundVariables boundVariables, int arity, TypeManager typeManager, FunctionRegistry functionRegistry)
  3. {
  4.   Type returnType = boundVariables.getTypeVariable("T");
  5.   return new ScalarFunctionImplementation(
  6.       true,
  7.       ImmutableList.of(functionTypeArgumentProperty(InvokeLambda.class)),
  8.       METHOD_HANDLE.asType(
  9.           METHOD_HANDLE.type()
  10.               .changeReturnType(wrap(returnType.getJavaType()))),
  11.       isDeterministic());
  12. }

代码示例来源：origin: prestodb/presto

  1. @Test
  2. public void testCustomStateSerializerAggregationParse()
  3. {
  4.   ParametricAggregation aggregation = parseFunctionDefinition(CustomStateSerializerAggregationFunction.class);
  5.   AggregationImplementation implementation = getOnlyElement(aggregation.getImplementations().getExactImplementations().values());
  6.   assertTrue(implementation.getStateSerializerFactory().isPresent());
  7.   InternalAggregationFunction specialized = aggregation.specialize(BoundVariables.builder().build(), 1, new TypeRegistry(), null);
  8.   AccumulatorStateSerializer<?> createdSerializer = getOnlyElement(((LazyAccumulatorFactoryBinder) specialized.getAccumulatorFactoryBinder())
  9.       .getGenericAccumulatorFactoryBinder().getStateDescriptors()).getSerializer();
  10.   Class<?> serializerFactory = implementation.getStateSerializerFactory().get().type().returnType();
  11.   assertTrue(serializerFactory.isInstance(createdSerializer));
  12. }

代码示例来源：origin: prestodb/presto

  1. @Override
  2.   public ScalarFunctionImplementation specialize(BoundVariables boundVariables, int arity, TypeManager typeManager, FunctionRegistry functionRegistry)
  3.   {
  4.     Type fromType = boundVariables.getTypeVariable("F");
  5.     Type toType = boundVariables.getTypeVariable("T");
  7.     Class<?> returnType = Primitives.wrap(toType.getJavaType());
  8.     List<ArgumentProperty> argumentProperties;
  9.     MethodHandle tryCastHandle;
  11.     // the resulting method needs to return a boxed type
  12.     Signature signature = functionRegistry.getCoercion(fromType, toType);
  13.     ScalarFunctionImplementation implementation = functionRegistry.getScalarFunctionImplementation(signature);
  14.     argumentProperties = ImmutableList.of(implementation.getArgumentProperty(0));
  15.     MethodHandle coercion = implementation.getMethodHandle();
  16.     coercion = coercion.asType(methodType(returnType, coercion.type()));
  18.     MethodHandle exceptionHandler = dropArguments(constant(returnType, null), 0, RuntimeException.class);
  19.     tryCastHandle = catchException(coercion, RuntimeException.class, exceptionHandler);
  21.     return new ScalarFunctionImplementation(true, argumentProperties, tryCastHandle, isDeterministic());
  22.   }
  23. }

代码示例来源：origin: prestodb/presto

  1. @Override
  2. public ScalarFunctionImplementation specialize(BoundVariables boundVariables, int arity, TypeManager typeManager, FunctionRegistry functionRegistry)
  3. {
  4.   Type argumentType = boundVariables.getTypeVariable("T");
  5.   Type returnType = boundVariables.getTypeVariable("U");
  6.   return new ScalarFunctionImplementation(
  7.       true,
  8.       ImmutableList.of(
  9.           valueTypeArgumentProperty(USE_BOXED_TYPE),
  10.           functionTypeArgumentProperty(UnaryFunctionInterface.class)),
  11.       METHOD_HANDLE.asType(
  12.           METHOD_HANDLE.type()
  13.               .changeReturnType(wrap(returnType.getJavaType()))
  14.               .changeParameterType(0, wrap(argumentType.getJavaType()))),
  15.       isDeterministic());
  16. }

代码示例来源：origin: prestodb/presto

  1. @Override
  2. public ScalarFunctionImplementation specialize(BoundVariables boundVariables, int arity, TypeManager typeManager, FunctionRegistry functionRegistry)
  3. {
  4.   Type inputType = boundVariables.getTypeVariable("T");
  5.   Type intermediateType = boundVariables.getTypeVariable("S");
  6.   Type outputType = boundVariables.getTypeVariable("R");
  7.   MethodHandle methodHandle = METHOD_HANDLE.bindTo(inputType);
  8.   return new ScalarFunctionImplementation(
  9.       true,
  10.       ImmutableList.of(
  11.           valueTypeArgumentProperty(RETURN_NULL_ON_NULL),
  12.           valueTypeArgumentProperty(USE_BOXED_TYPE),
  13.           functionTypeArgumentProperty(BinaryFunctionInterface.class),
  14.           functionTypeArgumentProperty(UnaryFunctionInterface.class)),
  15.       methodHandle.asType(
  16.           methodHandle.type()
  17.               .changeParameterType(1, Primitives.wrap(intermediateType.getJavaType()))
  18.               .changeReturnType(Primitives.wrap(outputType.getJavaType()))),
  19.       isDeterministic());
  20. }

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