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
[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: prestodb/presto
private static void verifyMethodParameterType(MethodHandle method, int index, Class javaType, String sqlTypeDisplayName)
{
checkArgument(method.type().parameterArray()[index] == javaType,
"Expected method %s parameter %s type to be %s (%s)",
method,
index,
javaType.getName(),
sqlTypeDisplayName);
}代码示例来源：origin: prestodb/presto
private static void verifyExactOutputFunction(MethodHandle method, List<AccumulatorStateDescriptor> stateDescriptors)
{
if (method == null) {
return;
}
Class<?>[] parameterTypes = method.type().parameterArray();
checkArgument(parameterTypes.length == stateDescriptors.size() + 1, "Number of arguments for combine function must be exactly one plus than number of states.");
for (int i = 0; i < stateDescriptors.size(); i++) {
checkArgument(parameterTypes[i].equals(stateDescriptors.get(i).getStateInterface()), String.format("Type for Parameter index %d is unexpected", i));
}
checkArgument(Arrays.stream(parameterTypes).filter(type -> type.equals(BlockBuilder.class)).count() == 1, "Output function must take exactly one BlockBuilder parameter");
}代码示例来源：origin: prestodb/presto
/**
* @param f (U, S1, S2, ..., Sm)R
* @param g (T1, T2, ..., Tn)U
* @return (T1, T2, ..., Tn, S1, S2, ..., Sm)R
*/
public static MethodHandle compose(MethodHandle f, MethodHandle g)
{
if (f.type().parameterType(0) != g.type().returnType()) {
throw new IllegalArgumentException(format("f.parameter(0) != g.return(). f: %s g: %s", f.type(), g.type()));
}
// Semantics: f => f
// Type: (U, S1, S2, ..., Sn)R => (U, T1, T2, ..., Tm, S1, S2, ..., Sn)R
MethodHandle fUTS = MethodHandles.dropArguments(f, 1, g.type().parameterList());
// Semantics: f => fg
// Type: (U, T1, T2, ..., Tm, S1, S2, ..., Sn)R => (T1, T2, ..., Tm, S1, S2, ..., Sn)R
return MethodHandles.foldArguments(fUTS, g);
}代码示例来源：origin: prestodb/presto
/**
* @param f (U, S1, S2, ..., Sm)R
* @param g (T1, T2, ..., Tn)U
* @return (T1, T2, ..., Tn, S1, S2, ..., Sm)R
*/
public static MethodHandle compose(MethodHandle f, MethodHandle g)
{
if (f.type().parameterType(0) != g.type().returnType()) {
throw new IllegalArgumentException(format("f.parameter(0) != g.return(). f: %s g: %s", f.type(), g.type()));
}
// Semantics: f => f
// Type: (U, S1, S2, ..., Sn)R => (U, T1, T2, ..., Tm, S1, S2, ..., Sn)R
MethodHandle fUTS = MethodHandles.dropArguments(f, 1, g.type().parameterList());
// Semantics: f => fg
// Type: (U, T1, T2, ..., Tm, S1, S2, ..., Sn)R => (T1, T2, ..., Tm, S1, S2, ..., Sn)R
return MethodHandles.foldArguments(fUTS, g);
}代码示例来源：origin: prestodb/presto
private static void verifyCombineFunction(MethodHandle method, List<Class> lambdaInterfaces, List<AccumulatorStateDescriptor> stateDescriptors)
{
Class<?>[] parameterTypes = method.type().parameterArray();
checkArgument(
parameterTypes.length == stateDescriptors.size() * 2 + lambdaInterfaces.size(),
"Number of arguments for combine function must be 2 times the size of states plus number of lambda channels.");
for (int i = 0; i < stateDescriptors.size() * 2; i++) {
checkArgument(
parameterTypes[i].equals(stateDescriptors.get(i % stateDescriptors.size()).getStateInterface()),
String.format("Type for Parameter index %d is unexpected. Arguments for combine function must appear in the order of state1, state2, ..., otherState1, otherState2, ...", i));
}
for (int i = 0; i < lambdaInterfaces.size(); i++) {
verifyMethodParameterType(method, i + stateDescriptors.size() * 2, lambdaInterfaces.get(i), "function");
}
}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: prestodb/presto
public FieldDefinition getCachedInstance(MethodHandle methodHandle)
{
FieldDefinition field = classDefinition.declareField(a(PRIVATE, FINAL), "__cachedInstance" + nextId, methodHandle.type().returnType());
initializers.put(field, methodHandle);
nextId++;
return field;
}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
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: 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: prestodb/presto
private void validateProcedure(Procedure procedure)
{
List<Class<?>> parameters = procedure.getMethodHandle().type().parameterList().stream()
.filter(type -> !ConnectorSession.class.isAssignableFrom(type))
.collect(toList());
for (int i = 0; i < procedure.getArguments().size(); i++) {
Argument argument = procedure.getArguments().get(i);
Type type = typeManager.getType(argument.getType());
Class<?> argumentType = Primitives.unwrap(parameters.get(i));
Class<?> expectedType = getObjectType(type);
checkArgument(expectedType.equals(argumentType),
"Argument '%s' has invalid type %s (expected %s)",
argument.getName(),
argumentType.getName(),
expectedType.getName());
}
}代码示例来源：origin: prestodb/presto
private InvokeFunctionBytecodeExpression(
Scope scope,
CallSiteBinder binder,
String name,
ScalarFunctionImplementation function,
Optional<BytecodeNode> instance,
List<BytecodeExpression> parameters)
{
super(type(Primitives.unwrap(function.getMethodHandle().type().returnType())));
this.invocation = generateInvocation(
scope,
name,
function,
instance,
parameters.stream().map(BytecodeNode.class::cast).collect(toImmutableList()),
binder);
this.oneLineDescription = name + "(" + Joiner.on(", ").join(parameters) + ")";
}代码示例来源：origin: apache/kafka
private static MethodHandle unmapJava7Or8(MethodHandles.Lookup lookup) throws ReflectiveOperationException {
/* "Compile" a MethodHandle that is roughly equivalent to the following lambda:
*
* (ByteBuffer buffer) -> {
* sun.misc.Cleaner cleaner = ((java.nio.DirectByteBuffer) byteBuffer).cleaner();
* if (nonNull(cleaner))
* cleaner.clean();
* else
* noop(cleaner); // the noop is needed because MethodHandles#guardWithTest always needs both if and else
* }
*/
Class<?> directBufferClass = Class.forName("java.nio.DirectByteBuffer");
Method m = directBufferClass.getMethod("cleaner");
m.setAccessible(true);
MethodHandle directBufferCleanerMethod = lookup.unreflect(m);
Class<?> cleanerClass = directBufferCleanerMethod.type().returnType();
MethodHandle cleanMethod = lookup.findVirtual(cleanerClass, "clean", methodType(void.class));
MethodHandle nonNullTest = lookup.findStatic(MappedByteBuffers.class, "nonNull",
methodType(boolean.class, Object.class)).asType(methodType(boolean.class, cleanerClass));
MethodHandle noop = dropArguments(constant(Void.class, null).asType(methodType(void.class)), 0, cleanerClass);
MethodHandle unmapper = filterReturnValue(directBufferCleanerMethod, guardWithTest(nonNullTest, cleanMethod, noop))
.asType(methodType(void.class, ByteBuffer.class));
return unmapper;
}代码示例来源：origin: prestodb/presto
@Override
public ScalarFunctionImplementation specialize(
BoundVariables boundVariables, int arity, TypeManager typeManager,
FunctionRegistry functionRegistry)
{
Type toType = boundVariables.getTypeVariable("E");
MethodHandle methodHandle = METHOD_HANDLE_NON_NULL.asType(METHOD_HANDLE_NON_NULL.type().changeReturnType(toType.getJavaType()));
return new ScalarFunctionImplementation(
false,
ImmutableList.of(valueTypeArgumentProperty(RETURN_NULL_ON_NULL)),
methodHandle,
isDeterministic());
}代码示例来源：origin: prestodb/presto
@Override
public ScalarFunctionImplementation specialize(BoundVariables boundVariables, int arity, TypeManager typeManager, FunctionRegistry functionRegistry)
{
Type returnType = boundVariables.getTypeVariable("T");
return new ScalarFunctionImplementation(
true,
ImmutableList.of(functionTypeArgumentProperty(InvokeLambda.class)),
METHOD_HANDLE.asType(
METHOD_HANDLE.type()
.changeReturnType(wrap(returnType.getJavaType()))),
isDeterministic());
}代码示例来源：origin: prestodb/presto
@Test
public void testCustomStateSerializerAggregationParse()
{
ParametricAggregation aggregation = parseFunctionDefinition(CustomStateSerializerAggregationFunction.class);
AggregationImplementation implementation = getOnlyElement(aggregation.getImplementations().getExactImplementations().values());
assertTrue(implementation.getStateSerializerFactory().isPresent());
InternalAggregationFunction specialized = aggregation.specialize(BoundVariables.builder().build(), 1, new TypeRegistry(), null);
AccumulatorStateSerializer<?> createdSerializer = getOnlyElement(((LazyAccumulatorFactoryBinder) specialized.getAccumulatorFactoryBinder())
.getGenericAccumulatorFactoryBinder().getStateDescriptors()).getSerializer();
Class<?> serializerFactory = implementation.getStateSerializerFactory().get().type().returnType();
assertTrue(serializerFactory.isInstance(createdSerializer));
}代码示例来源：origin: prestodb/presto
@Override
public ScalarFunctionImplementation specialize(BoundVariables boundVariables, int arity, TypeManager typeManager, FunctionRegistry functionRegistry)
{
Type fromType = boundVariables.getTypeVariable("F");
Type toType = boundVariables.getTypeVariable("T");
Class<?> returnType = Primitives.wrap(toType.getJavaType());
List<ArgumentProperty> argumentProperties;
MethodHandle tryCastHandle;
// the resulting method needs to return a boxed type
Signature signature = functionRegistry.getCoercion(fromType, toType);
ScalarFunctionImplementation implementation = functionRegistry.getScalarFunctionImplementation(signature);
argumentProperties = ImmutableList.of(implementation.getArgumentProperty(0));
MethodHandle coercion = implementation.getMethodHandle();
coercion = coercion.asType(methodType(returnType, coercion.type()));
MethodHandle exceptionHandler = dropArguments(constant(returnType, null), 0, RuntimeException.class);
tryCastHandle = catchException(coercion, RuntimeException.class, exceptionHandler);
return new ScalarFunctionImplementation(true, argumentProperties, tryCastHandle, isDeterministic());
}
}代码示例来源：origin: prestodb/presto
@Override
public ScalarFunctionImplementation specialize(BoundVariables boundVariables, int arity, TypeManager typeManager, FunctionRegistry functionRegistry)
{
Type argumentType = boundVariables.getTypeVariable("T");
Type returnType = boundVariables.getTypeVariable("U");
return new ScalarFunctionImplementation(
true,
ImmutableList.of(
valueTypeArgumentProperty(USE_BOXED_TYPE),
functionTypeArgumentProperty(UnaryFunctionInterface.class)),
METHOD_HANDLE.asType(
METHOD_HANDLE.type()
.changeReturnType(wrap(returnType.getJavaType()))
.changeParameterType(0, wrap(argumentType.getJavaType()))),
isDeterministic());
}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());
}内容来源于网络，如有侵权，请联系作者删除！