public static MethodHandle identity(Wrapper wrap) {
EnumMap<Wrapper, MethodHandle> cache = CONSTANT_FUNCTIONS[1];
MethodHandle mh = cache.get(wrap);
if (mh != null) {
return mh;
}
// slow path
MethodType type = MethodType.methodType(wrap.primitiveType());
if (wrap != Wrapper.VOID) type = type.appendParameterTypes(wrap.primitiveType());
try {
mh = IMPL_LOOKUP.findStatic(THIS_CLASS, "identity", type);
} catch (ReflectiveOperationException ex) {
mh = null;
}
if (mh == null && wrap == Wrapper.VOID) {
mh = EMPTY; // #(){} : #()void
}
if (mh != null) {
cache.put(wrap, mh);
return mh;
}
if (mh != null) {
cache.put(wrap, mh);
return mh;
}
throw new IllegalArgumentException("cannot find identity for " + wrap);
}
static {
try {
MethodType idType = MethodType.genericMethodType(1);
MethodType castType = idType.insertParameterTypes(0, Class.class);
MethodType ignoreType = idType.changeReturnType(void.class);
MethodType zeroObjectType = MethodType.genericMethodType(0);
IDENTITY = IMPL_LOOKUP.findStatic(THIS_CLASS, "identity", idType);
// CAST_REFERENCE = IMPL_LOOKUP.findVirtual(Class.class, "cast", idType);
CAST_REFERENCE = IMPL_LOOKUP.findStatic(THIS_CLASS, "castReference", castType);
ZERO_OBJECT = IMPL_LOOKUP.findStatic(THIS_CLASS, "zeroObject", zeroObjectType);
IGNORE = IMPL_LOOKUP.findStatic(THIS_CLASS, "ignore", ignoreType);
EMPTY = IMPL_LOOKUP.findStatic(THIS_CLASS, "empty", ignoreType.dropParameterTypes(0, 1));
ARRAY_IDENTITY =
IMPL_LOOKUP.findStatic(
THIS_CLASS, "identity", MethodType.methodType(Object[].class, Object[].class));
FILL_NEW_ARRAY =
IMPL_LOOKUP.findStatic(
THIS_CLASS,
"fillNewArray",
MethodType.methodType(Object[].class, Integer.class, Object[].class));
FILL_NEW_TYPED_ARRAY =
IMPL_LOOKUP.findStatic(
THIS_CLASS,
"fillNewTypedArray",
MethodType.methodType(Object[].class, Object[].class, Integer.class, Object[].class));
} catch (NoSuchMethodException | IllegalAccessException ex) {
throw newInternalError("uncaught exception", ex);
}
}
/**
* Return a method handle that takes the indicated number of typed arguments and returns an array
* of them. The type argument is the array type.
*/
public static MethodHandle varargsArray(Class<?> arrayType, int nargs) {
Class<?> elemType = arrayType.getComponentType();
if (elemType == null) throw new IllegalArgumentException("not an array: " + arrayType);
// FIXME: Need more special casing and caching here.
if (nargs >= MAX_JVM_ARITY / 2 - 1) {
int slots = nargs;
final int MAX_ARRAY_SLOTS = MAX_JVM_ARITY - 1; // 1 for receiver MH
if (arrayType == double[].class || arrayType == long[].class) slots *= 2;
if (slots > MAX_ARRAY_SLOTS)
throw new IllegalArgumentException(
"too many arguments: " + arrayType.getSimpleName() + ", length " + nargs);
}
if (elemType == Object.class) return varargsArray(nargs);
// other cases: primitive arrays, subtypes of Object[]
MethodHandle cache[] = TYPED_COLLECTORS.get(elemType);
MethodHandle mh = nargs < cache.length ? cache[nargs] : null;
if (mh != null) return mh;
if (elemType.isPrimitive()) {
MethodHandle builder = FILL_NEW_ARRAY;
MethodHandle producer = buildArrayProducer(arrayType);
mh = buildVarargsArray(builder, producer, nargs);
} else {
@SuppressWarnings("unchecked")
Class<? extends Object[]> objArrayType = (Class<? extends Object[]>) arrayType;
Object[] example = Arrays.copyOf(NO_ARGS_ARRAY, 0, objArrayType);
MethodHandle builder = FILL_NEW_TYPED_ARRAY.bindTo(example);
MethodHandle producer = ARRAY_IDENTITY;
mh = buildVarargsArray(builder, producer, nargs);
}
mh =
mh.asType(MethodType.methodType(arrayType, Collections.<Class<?>>nCopies(nargs, elemType)));
assert (assertCorrectArity(mh, nargs));
if (nargs < cache.length) cache[nargs] = mh;
return mh;
}
private static MethodHandle findCollector(
String name, int nargs, Class<?> rtype, Class<?>... ptypes) {
MethodType type =
MethodType.genericMethodType(nargs).changeReturnType(rtype).insertParameterTypes(0, ptypes);
try {
return IMPL_LOOKUP.findStatic(THIS_CLASS, name, type);
} catch (ReflectiveOperationException ex) {
return null;
}
}
public static MethodHandle convertPrimitive(Wrapper wsrc, Wrapper wdst) {
EnumMap<Wrapper, MethodHandle> cache = CONVERT_PRIMITIVE_FUNCTIONS[wsrc.ordinal()];
MethodHandle mh = cache.get(wdst);
if (mh != null) {
return mh;
}
// slow path
Class<?> src = wsrc.primitiveType();
Class<?> dst = wdst.primitiveType();
MethodType type =
src == void.class ? MethodType.methodType(dst) : MethodType.methodType(dst, src);
if (wsrc == wdst) {
mh = identity(src);
} else if (wsrc == Wrapper.VOID) {
mh = zeroConstantFunction(wdst);
} else if (wdst == Wrapper.VOID) {
mh = MethodHandles.dropArguments(EMPTY, 0, src); // Defer back to MethodHandles.
} else if (wsrc == Wrapper.OBJECT) {
mh = unboxCast(dst);
} else if (wdst == Wrapper.OBJECT) {
mh = box(src);
} else {
assert (src.isPrimitive() && dst.isPrimitive());
try {
mh =
IMPL_LOOKUP.findStatic(
THIS_CLASS, src.getSimpleName() + "To" + capitalize(dst.getSimpleName()), type);
} catch (ReflectiveOperationException ex) {
mh = null;
}
}
if (mh != null) {
assert (mh.type() == type) : mh;
cache.put(wdst, mh);
return mh;
}
throw new IllegalArgumentException(
"cannot find primitive conversion function for "
+ src.getSimpleName()
+ " -> "
+ dst.getSimpleName());
}
static {
try {
// MAKE_ARRAY = IMPL_LOOKUP.findStatic(THIS_CLASS, "makeArray",
// MethodType.methodType(Object[].class, Object[].class));
COPY_AS_REFERENCE_ARRAY =
IMPL_LOOKUP.findStatic(
THIS_CLASS,
"copyAsReferenceArray",
MethodType.methodType(Object[].class, Class.class, Object[].class));
COPY_AS_PRIMITIVE_ARRAY =
IMPL_LOOKUP.findStatic(
THIS_CLASS,
"copyAsPrimitiveArray",
MethodType.methodType(Object.class, Wrapper.class, Object[].class));
MAKE_LIST =
IMPL_LOOKUP.findStatic(
THIS_CLASS, "makeList", MethodType.methodType(List.class, Object[].class));
} catch (ReflectiveOperationException ex) {
throw newInternalError("uncaught exception", ex);
}
}
private static MethodHandle box(Wrapper wrap, boolean exact) {
EnumMap<Wrapper, MethodHandle> cache = BOX_CONVERSIONS[(exact ? 1 : 0)];
MethodHandle mh = cache.get(wrap);
if (mh != null) {
return mh;
}
// slow path
switch (wrap) {
case OBJECT:
mh = IDENTITY;
break;
case VOID:
mh = ZERO_OBJECT;
break;
}
if (mh != null) {
cache.put(wrap, mh);
return mh;
}
// look up the method
String name = "box" + wrap.wrapperSimpleName();
MethodType type = boxType(wrap);
if (exact) {
try {
mh = IMPL_LOOKUP.findStatic(THIS_CLASS, name, type);
} catch (ReflectiveOperationException ex) {
mh = null;
}
} else {
mh = box(wrap, !exact).asType(type.erase());
}
if (mh != null) {
cache.put(wrap, mh);
return mh;
}
throw new IllegalArgumentException(
"cannot find box adapter for " + wrap + (exact ? " (exact)" : ""));
}
public static MethodHandle zeroConstantFunction(Wrapper wrap) {
EnumMap<Wrapper, MethodHandle> cache = CONSTANT_FUNCTIONS[0];
MethodHandle mh = cache.get(wrap);
if (mh != null) {
return mh;
}
// slow path
MethodType type = MethodType.methodType(wrap.primitiveType());
switch (wrap) {
case VOID:
mh = EMPTY;
break;
case OBJECT:
case INT:
case LONG:
case FLOAT:
case DOUBLE:
try {
mh = IMPL_LOOKUP.findStatic(THIS_CLASS, "zero" + wrap.wrapperSimpleName(), type);
} catch (ReflectiveOperationException ex) {
mh = null;
}
break;
}
if (mh != null) {
cache.put(wrap, mh);
return mh;
}
// use zeroInt and cast the result
if (wrap.isSubwordOrInt() && wrap != Wrapper.INT) {
mh = MethodHandles.explicitCastArguments(zeroConstantFunction(Wrapper.INT), type);
cache.put(wrap, mh);
return mh;
}
throw new IllegalArgumentException("cannot find zero constant for " + wrap);
}
private static MethodType boxType(Wrapper wrap) {
// be exact, since return casts are hard to compose
Class<?> boxType = wrap.wrapperType();
return MethodType.methodType(boxType, wrap.primitiveType());
}
private static MethodType unboxType(Wrapper wrap) {
return MethodType.methodType(wrap.primitiveType(), Object.class, boolean.class);
}