本文整理汇总了Java中jdk.internal.dynalink.linker.LinkerServices.asType方法的典型用法代码示例。如果您正苦于以下问题:Java LinkerServices.asType方法的具体用法?Java LinkerServices.asType怎么用?Java LinkerServices.asType使用的例子?那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类jdk.internal.dynalink.linker.LinkerServices
的用法示例。
在下文中一共展示了LinkerServices.asType方法的2个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的Java代码示例。
示例1: getPropertySetter
import jdk.internal.dynalink.linker.LinkerServices; //导入方法依赖的package包/类
private GuardedInvocationComponent getPropertySetter(final CallSiteDescriptor callSiteDescriptor,
final LinkerServices linkerServices, final List<String> operations) throws Exception {
switch(callSiteDescriptor.getNameTokenCount()) {
case 2: {
// Must have three arguments: target object, property name, and property value.
assertParameterCount(callSiteDescriptor, 3);
// We want setters that conform to "Object(O, V)". Note, we aren't doing "R(O, V)" as it might not be
// valid for us to convert return values proactively. Also, since we don't know what setters will be
// invoked, we'll conservatively presume Object return type. The one exception is void return.
final MethodType origType = callSiteDescriptor.getMethodType();
final MethodType type = origType.returnType() == void.class ? origType : origType.changeReturnType(Object.class);
// What's below is basically:
// foldArguments(guardWithTest(isNotNull, invoke, null|nextComponent.invocation),
// get_setter_handle(type, linkerServices))
// only with a bunch of method signature adjustments. Basically, retrieve method setter
// MethodHandle; if it is non-null, invoke it, otherwise either return null, or delegate to next
// component's invocation.
// Call site type is "ret_type(object_type,property_name_type,property_value_type)", which we'll
// abbreviate to R(O, N, V) going forward, although we don't really use R here (see above about using
// Object return type).
final MethodType setterType = type.dropParameterTypes(1, 2);
// Bind property setter handle to the expected setter type and linker services. Type is
// MethodHandle(Object, String, Object)
final MethodHandle boundGetter = MethodHandles.insertArguments(getPropertySetterHandle, 0,
callSiteDescriptor.changeMethodType(setterType), linkerServices);
// Cast getter to MethodHandle(O, N, V)
final MethodHandle typedGetter = linkerServices.asType(boundGetter, type.changeReturnType(
MethodHandle.class));
// Handle to invoke the setter R(MethodHandle, O, V)
final MethodHandle invokeHandle = MethodHandles.exactInvoker(setterType);
// Handle to invoke the setter, dropping unnecessary fold arguments R(MethodHandle, O, N, V)
final MethodHandle invokeHandleFolded = MethodHandles.dropArguments(invokeHandle, 2, type.parameterType(
1));
final GuardedInvocationComponent nextComponent = getGuardedInvocationComponent(callSiteDescriptor,
linkerServices, operations);
final MethodHandle fallbackFolded;
if(nextComponent == null) {
// Object(MethodHandle)->Object(MethodHandle, O, N, V); returns constant null
fallbackFolded = MethodHandles.dropArguments(CONSTANT_NULL_DROP_METHOD_HANDLE, 1,
type.parameterList()).asType(type.insertParameterTypes(0, MethodHandle.class));
} else {
// Object(O, N, V)->Object(MethodHandle, O, N, V); adapts the next component's invocation to drop the
// extra argument resulting from fold
fallbackFolded = MethodHandles.dropArguments(nextComponent.getGuardedInvocation().getInvocation(),
0, MethodHandle.class);
}
// fold(R(MethodHandle, O, N, V), MethodHandle(O, N, V))
final MethodHandle compositeSetter = MethodHandles.foldArguments(MethodHandles.guardWithTest(
IS_METHOD_HANDLE_NOT_NULL, invokeHandleFolded, fallbackFolded), typedGetter);
if(nextComponent == null) {
return getClassGuardedInvocationComponent(compositeSetter, type);
}
return nextComponent.compose(compositeSetter, getClassGuard(type), clazz, ValidationType.EXACT_CLASS);
}
case 3: {
// Must have two arguments: target object and property value
assertParameterCount(callSiteDescriptor, 2);
final GuardedInvocation gi = createGuardedDynamicMethodInvocation(callSiteDescriptor, linkerServices,
callSiteDescriptor.getNameToken(CallSiteDescriptor.NAME_OPERAND), propertySetters);
// If we have a property setter with this name, this composite operation will always stop here
if(gi != null) {
return new GuardedInvocationComponent(gi, clazz, ValidationType.EXACT_CLASS);
}
// If we don't have a property setter with this name, always fall back to the next operation in the
// composite (if any)
return getGuardedInvocationComponent(callSiteDescriptor, linkerServices, operations);
}
default: {
// More than two name components; don't know what to do with it.
return null;
}
}
}
示例2: asType
import jdk.internal.dynalink.linker.LinkerServices; //导入方法依赖的package包/类
/**
* Takes a guard-test method handle, and adapts it to the requested type, returning a boolean. Applies the passed
* {@link LinkerServices} object's {@link LinkerServices#asType(MethodHandle, MethodType)}.
* @param linkerServices the linker services to use for type conversions
* @param test the test method handle
* @param type the type to adapt the method handle to
* @return the adapted method handle
*/
public static MethodHandle asType(final LinkerServices linkerServices, final MethodHandle test, final MethodType type) {
return linkerServices.asType(test, getTestType(test, type));
}