private boolean returnConversionNeeded(MethodType callerType, MethodHandle target) {
Class<?> needType = callerType.returnType();
if (needType == erasedCallerType.returnType())
return false; // no conversions possible, since must be primitive or Object
Class<?> haveType = target.type().returnType();
if (VerifyType.isNullConversion(haveType, needType) && !needType.isInterface()) return false;
return true;
}
/**
* Compute and cache information for this adapter, so that it can call out to targets of the
* erasure-family of the given erased type.
*/
/*non-public*/ InvokeGeneric(MethodType erasedCallerType) throws ReflectiveOperationException {
assert (erasedCallerType.equals(erasedCallerType.erase()));
this.erasedCallerType = erasedCallerType;
this.initialInvoker = makeInitialInvoker();
assert initialInvoker
.type()
.equals(erasedCallerType.insertParameterTypes(0, MethodType.class, MethodHandle.class))
: initialInvoker.type();
}
private MethodHandle addReturnConversion(MethodHandle finisher, Class<?> type) {
// FIXME: This is slow because it creates a closure node on every call that requires a return
// cast.
MethodType finisherType = finisher.type();
MethodHandle caster = ValueConversions.identity(type);
caster = caster.asType(caster.type().changeParameterType(0, finisherType.returnType()));
finisher = MethodHandles.filterReturnValue(finisher, caster);
return finisher.asType(finisherType);
}
/**
* Return a method handle to invoke on the callerType, target, and remaining arguments. The method
* handle must finish the call. This is the first look at the caller type and target.
*/
private MethodHandle dispatch(MethodType callerType, MethodHandle target) {
MethodType targetType = target.type();
if (USE_AS_TYPE_PATH || target.isVarargsCollector()) {
MethodHandle newTarget = target.asType(callerType);
targetType = callerType;
Invokers invokers = targetType.invokers();
MethodHandle invoker = invokers.erasedInvokerWithDrops;
if (invoker == null) {
invokers.erasedInvokerWithDrops = invoker = dropDispatchArguments(invokers.erasedInvoker());
}
return invoker.bindTo(newTarget);
}
throw new RuntimeException("NYI");
}
private MethodHandle dispatcher(String dispatchName) throws ReflectiveOperationException {
return lookup()
.bind(
this,
dispatchName,
MethodType.methodType(MethodHandle.class, MethodType.class, MethodHandle.class));
}
private MethodHandle makePostDispatchInvoker() {
// Take (MH'; MT, MH; A...) and run MH'(MT, MH; A...).
MethodType invokerType = erasedCallerType.insertParameterTypes(0, EXTRA_ARGS);
return invokerType.invokers().exactInvoker();
}
private boolean returnConversionPossible() {
Class<?> needType = erasedCallerType.returnType();
return !needType.isPrimitive();
}
private MethodHandle dispatchWithConversion(MethodType callerType, MethodHandle target) {
MethodHandle finisher = dispatch(callerType, target);
if (returnConversionNeeded(callerType, target))
finisher = addReturnConversion(finisher, callerType.returnType()); // FIXME: slow
return finisher;
}