下面列出了java.lang.invoke.MethodHandles#permuteArguments ( ) 实例代码,或者点击链接到github查看源代码,也可以在右侧发表评论。
@Test
public void testReturnOnStack() throws Throwable {
MethodHandles.Lookup l = MethodHandles.lookup();
MethodHandle consumeIdentity = l.findStatic(
PermuteArgsReturnVoidTest.class, "consumeIdentity",
MethodType.methodType(String.class, String.class, int.class, int.class));
MethodHandle consumeVoid = l.findStatic(
PermuteArgsReturnVoidTest.class, "consumeVoid",
MethodType.methodType(void.class, String.class, int.class, int.class));
MethodHandle f = MethodHandles.foldArguments(consumeIdentity, consumeVoid);
MethodHandle p = MethodHandles.permuteArguments(f, MethodType.methodType(String.class, String.class, int.class, int.class), 0, 2, 1);
String s = (String) p.invoke("IN", 0, 0);
Assert.assertEquals(s.getClass(), String.class);
Assert.assertEquals(s, "IN");
}
@Test
public void testReturnFromArg() throws Throwable {
MethodHandles.Lookup l = MethodHandles.lookup();
MethodHandle consumeIdentity = dropArguments(
identity(String.class), 1, int.class, int.class);
MethodHandle consumeVoid = l.findStatic(
PermuteArgsReturnVoidTest.class, "consumeVoid",
MethodType.methodType(void.class, String.class, int.class, int.class));
MethodHandle f = MethodHandles.foldArguments(consumeIdentity, consumeVoid);
MethodHandle p = MethodHandles.permuteArguments(f, MethodType.methodType(String.class, String.class, int.class, int.class), 0, 2, 1);
String s = (String) p.invoke("IN", 0, 0);
Assert.assertEquals(s.getClass(), String.class);
Assert.assertEquals(s, "IN");
}
@Test
public void testReturnOnStack() throws Throwable {
MethodHandles.Lookup l = MethodHandles.lookup();
MethodHandle consumeIdentity = l.findStatic(
PermuteArgsReturnVoidTest.class, "consumeIdentity",
MethodType.methodType(String.class, String.class, int.class, int.class));
MethodHandle consumeVoid = l.findStatic(
PermuteArgsReturnVoidTest.class, "consumeVoid",
MethodType.methodType(void.class, String.class, int.class, int.class));
MethodHandle f = MethodHandles.foldArguments(consumeIdentity, consumeVoid);
MethodHandle p = MethodHandles.permuteArguments(f, MethodType.methodType(String.class, String.class, int.class, int.class), 0, 2, 1);
String s = (String) p.invoke("IN", 0, 0);
Assert.assertEquals(s.getClass(), String.class);
Assert.assertEquals(s, "IN");
}
@Test
public void testReturnFromArg() throws Throwable {
MethodHandles.Lookup l = MethodHandles.lookup();
MethodHandle consumeIdentity = dropArguments(
identity(String.class), 1, int.class, int.class);
MethodHandle consumeVoid = l.findStatic(
PermuteArgsReturnVoidTest.class, "consumeVoid",
MethodType.methodType(void.class, String.class, int.class, int.class));
MethodHandle f = MethodHandles.foldArguments(consumeIdentity, consumeVoid);
MethodHandle p = MethodHandles.permuteArguments(f, MethodType.methodType(String.class, String.class, int.class, int.class), 0, 2, 1);
String s = (String) p.invoke("IN", 0, 0);
Assert.assertEquals(s.getClass(), String.class);
Assert.assertEquals(s, "IN");
}
@Test
public void testReturnOnStack() throws Throwable {
MethodHandles.Lookup l = MethodHandles.lookup();
MethodHandle consumeIdentity = l.findStatic(
PermuteArgsReturnVoidTest.class, "consumeIdentity",
MethodType.methodType(String.class, String.class, int.class, int.class));
MethodHandle consumeVoid = l.findStatic(
PermuteArgsReturnVoidTest.class, "consumeVoid",
MethodType.methodType(void.class, String.class, int.class, int.class));
MethodHandle f = MethodHandles.foldArguments(consumeIdentity, consumeVoid);
MethodHandle p = MethodHandles.permuteArguments(f, MethodType.methodType(String.class, String.class, int.class, int.class), 0, 2, 1);
String s = (String) p.invoke("IN", 0, 0);
Assert.assertEquals(s.getClass(), String.class);
Assert.assertEquals(s, "IN");
}
@Test
public void testReturnFromArg() throws Throwable {
MethodHandles.Lookup l = MethodHandles.lookup();
MethodHandle consumeIdentity = dropArguments(
identity(String.class), 1, int.class, int.class);
MethodHandle consumeVoid = l.findStatic(
PermuteArgsReturnVoidTest.class, "consumeVoid",
MethodType.methodType(void.class, String.class, int.class, int.class));
MethodHandle f = MethodHandles.foldArguments(consumeIdentity, consumeVoid);
MethodHandle p = MethodHandles.permuteArguments(f, MethodType.methodType(String.class, String.class, int.class, int.class), 0, 2, 1);
String s = (String) p.invoke("IN", 0, 0);
Assert.assertEquals(s.getClass(), String.class);
Assert.assertEquals(s, "IN");
}
private static MethodHandle buildSetter(Class<?> arrayClass) {
MethodHandle set = MethodHandles.arrayElementSetter(arrayClass);
MethodHandle fallback = MethodHandles.explicitCastArguments(set, set.type().changeParameterType(0, Object.class));
fallback = MethodHandles.dropArguments(fallback, 3, int.class);
MethodType reorderType = fallback.type().
insertParameterTypes(0, int.class).
dropParameterTypes(4, 5);
fallback = MethodHandles.permuteArguments(fallback, reorderType, 1, 0, 3, 0);
fallback = MethodHandles.foldArguments(fallback, normalizeIndex);
fallback = MethodHandles.explicitCastArguments(fallback, set.type());
MethodHandle guard = MethodHandles.dropArguments(notNegative, 0, arrayClass);
MethodHandle handle = MethodHandles.guardWithTest(guard, set, fallback);
return handle;
}
@Test
public void testReturnFromArg() throws Throwable {
MethodHandles.Lookup l = MethodHandles.lookup();
MethodHandle consumeIdentity = dropArguments(
identity(String.class), 1, int.class, int.class);
MethodHandle consumeVoid = l.findStatic(
PermuteArgsReturnVoidTest.class, "consumeVoid",
MethodType.methodType(void.class, String.class, int.class, int.class));
MethodHandle f = MethodHandles.foldArguments(consumeIdentity, consumeVoid);
MethodHandle p = MethodHandles.permuteArguments(f, MethodType.methodType(String.class, String.class, int.class, int.class), 0, 2, 1);
String s = (String) p.invoke("IN", 0, 0);
Assert.assertEquals(s.getClass(), String.class);
Assert.assertEquals(s, "IN");
}
@Test
public void testReturnFromArg() throws Throwable {
MethodHandles.Lookup l = MethodHandles.lookup();
MethodHandle consumeIdentity = dropArguments(
identity(String.class), 1, int.class, int.class);
MethodHandle consumeVoid = l.findStatic(
PermuteArgsReturnVoidTest.class, "consumeVoid",
MethodType.methodType(void.class, String.class, int.class, int.class));
MethodHandle f = MethodHandles.foldArguments(consumeIdentity, consumeVoid);
MethodHandle p = MethodHandles.permuteArguments(f, MethodType.methodType(String.class, String.class, int.class, int.class), 0, 2, 1);
String s = (String) p.invoke("IN", 0, 0);
Assert.assertEquals(s.getClass(), String.class);
Assert.assertEquals(s, "IN");
}
@Test
public void testReturnOnStack() throws Throwable {
MethodHandles.Lookup l = MethodHandles.lookup();
MethodHandle consumeIdentity = l.findStatic(
PermuteArgsReturnVoidTest.class, "consumeIdentity",
MethodType.methodType(String.class, String.class, int.class, int.class));
MethodHandle consumeVoid = l.findStatic(
PermuteArgsReturnVoidTest.class, "consumeVoid",
MethodType.methodType(void.class, String.class, int.class, int.class));
MethodHandle f = MethodHandles.foldArguments(consumeIdentity, consumeVoid);
MethodHandle p = MethodHandles.permuteArguments(f, MethodType.methodType(String.class, String.class, int.class, int.class), 0, 2, 1);
String s = (String) p.invoke("IN", 0, 0);
Assert.assertEquals(s.getClass(), String.class);
Assert.assertEquals(s, "IN");
}
@Test
public void testReturnFromArg() throws Throwable {
MethodHandles.Lookup l = MethodHandles.lookup();
MethodHandle consumeIdentity = dropArguments(
identity(String.class), 1, int.class, int.class);
MethodHandle consumeVoid = l.findStatic(
PermuteArgsReturnVoidTest.class, "consumeVoid",
MethodType.methodType(void.class, String.class, int.class, int.class));
MethodHandle f = MethodHandles.foldArguments(consumeIdentity, consumeVoid);
MethodHandle p = MethodHandles.permuteArguments(f, MethodType.methodType(String.class, String.class, int.class, int.class), 0, 2, 1);
String s = (String) p.invoke("IN", 0, 0);
Assert.assertEquals(s.getClass(), String.class);
Assert.assertEquals(s, "IN");
}
/**
* @param f (U, V)R
* @param g (S1, S2, ..., Sm)U
* @param h (T1, T2, ..., Tn)V
* @return (S1, S2, ..., Sm, T1, T2, ..., Tn)R
*/
public static MethodHandle compose(MethodHandle f, MethodHandle g, MethodHandle h)
{
if (f.type().parameterCount() != 2) {
throw new IllegalArgumentException(format("f.parameterCount != 2. f: %s", f.type()));
}
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()));
}
if (f.type().parameterType(1) != h.type().returnType()) {
throw new IllegalArgumentException(format("f.parameter(0) != h.return. f: %s h: %s", f.type(), h.type()));
}
// (V, T1, T2, ..., Tn, U)R
MethodType typeVTU = f.type().dropParameterTypes(0, 1).appendParameterTypes(h.type().parameterList()).appendParameterTypes(f.type().parameterType(0));
// Semantics: f => f
// Type: (U, V)R => (V, T1, T2, ..., Tn, U)R
MethodHandle fVTU = MethodHandles.permuteArguments(f, typeVTU, h.type().parameterCount() + 1, 0);
// Semantics: f => fh
// Type: (V, T1, T2, ..., Tn, U)R => (T1, T2, ..., Tn, U)R
MethodHandle fhTU = MethodHandles.foldArguments(fVTU, h);
// reorder: [m+1, m+2, ..., m+n, 0]
int[] reorder = new int[fhTU.type().parameterCount()];
for (int i = 0; i < reorder.length - 1; i++) {
reorder[i] = i + 1 + g.type().parameterCount();
}
reorder[reorder.length - 1] = 0;
// (U, S1, S2, ..., Sm, T1, T2, ..., Tn)R
MethodType typeUST = f.type().dropParameterTypes(1, 2).appendParameterTypes(g.type().parameterList()).appendParameterTypes(h.type().parameterList());
// Semantics: f.h => f.h
// Type: (T1, T2, ..., Tn, U)R => (U, S1, S2, ..., Sm, T1, T2, ..., Tn)R
MethodHandle fhUST = MethodHandles.permuteArguments(fhTU, typeUST, reorder);
// Semantics: fh => fgh
// Type: (U, S1, S2, ..., Sm, T1, T2, ..., Tn)R => (S1, S2, ..., Sm, T1, T2, ..., Tn)R
return MethodHandles.foldArguments(fhUST, g);
}
/**
* Generates a method handle for the {@code hashCode} method for a given data class
* @param receiverClass the data class
* @param getters the list of getters
* @return the method handle
*/
private static MethodHandle makeHashCode(Class<?> receiverClass,
List<MethodHandle> getters) {
MethodHandle accumulator = MethodHandles.dropArguments(ZERO, 0, receiverClass); // (R)I
// @@@ Use loop combinator instead?
for (MethodHandle getter : getters) {
MethodHandle hasher = hasher(getter.type().returnType()); // (T)I
MethodHandle hashThisField = MethodHandles.filterArguments(hasher, 0, getter); // (R)I
MethodHandle combineHashes = MethodHandles.filterArguments(HASH_COMBINER, 0, accumulator, hashThisField); // (RR)I
accumulator = MethodHandles.permuteArguments(combineHashes, accumulator.type(), 0, 0); // adapt (R)I to (RR)I
}
return accumulator;
}
static MethodHandle permute(MethodHandle h) {
// The handles representing virtual methods need to be rearranged to match the required order of arguments
// (loop-local state comes first, then loop arguments). As the receiver comes first in the signature but is
// a loop argument, it must be moved to the appropriate position in the signature.
return MethodHandles.permuteArguments(h,
methodType(h.type().returnType(), int.class, int.class, LOOP_WITH_VIRTUALS, int.class), 2, 0, 1, 3);
}
private static ScalarFunctionImplementation specializeArrayJoin(BoundVariables types, Metadata metadata, List<Boolean> nullableArguments, MethodHandle methodHandle)
{
Type type = types.getTypeVariable("T");
List<ArgumentProperty> argumentProperties = nullableArguments.stream()
.map(nullable -> nullable
? valueTypeArgumentProperty(USE_BOXED_TYPE)
: valueTypeArgumentProperty(RETURN_NULL_ON_NULL))
.collect(toImmutableList());
if (type instanceof UnknownType) {
return new ScalarFunctionImplementation(
false,
argumentProperties,
methodHandle.bindTo(null),
Optional.of(STATE_FACTORY));
}
else {
try {
ResolvedFunction resolvedFunction = metadata.getCoercion(type, VARCHAR);
MethodHandle cast = metadata.getScalarFunctionInvoker(resolvedFunction, Optional.empty()).getMethodHandle();
MethodHandle getter;
Class<?> elementType = type.getJavaType();
if (elementType == boolean.class) {
getter = GET_BOOLEAN;
}
else if (elementType == double.class) {
getter = GET_DOUBLE;
}
else if (elementType == long.class) {
getter = GET_LONG;
}
else if (elementType == Slice.class) {
getter = GET_SLICE;
}
else {
throw new UnsupportedOperationException("Unsupported type: " + elementType.getName());
}
// if the cast doesn't take a ConnectorSession, create an adapter that drops the provided session
if (cast.type().parameterArray()[0] != ConnectorSession.class) {
cast = MethodHandles.dropArguments(cast, 0, ConnectorSession.class);
}
// Adapt a target cast that takes (ConnectorSession, ?) to one that takes (Block, int, ConnectorSession), which will be invoked by the implementation
// The first two arguments (Block, int) are filtered through the element type's getXXX method to produce the underlying value that needs to be passed to
// the cast.
cast = MethodHandles.permuteArguments(cast, MethodType.methodType(Slice.class, cast.type().parameterArray()[1], cast.type().parameterArray()[0]), 1, 0);
cast = MethodHandles.dropArguments(cast, 1, int.class);
cast = MethodHandles.dropArguments(cast, 1, Block.class);
cast = MethodHandles.foldArguments(cast, getter.bindTo(type));
MethodHandle target = MethodHandles.insertArguments(methodHandle, 0, cast);
return new ScalarFunctionImplementation(
false,
argumentProperties,
target,
Optional.of(STATE_FACTORY));
}
catch (PrestoException e) {
throw new PrestoException(INVALID_FUNCTION_ARGUMENT, format("Input type %s not supported", type), e);
}
}
}
private static MethodHandle constantBoolean(final Boolean value, final MethodType type) {
return MethodHandles.permuteArguments(MethodHandles.constant(Boolean.TYPE, value),
type.changeReturnType(Boolean.TYPE));
}
private static MethodHandle constantBoolean(final Boolean value, final MethodType type) {
return MethodHandles.permuteArguments(MethodHandles.constant(Boolean.TYPE, value),
type.changeReturnType(Boolean.TYPE));
}
protected MethodHandle initMethodHandle(ServicesAmp ampManager,
Method method)
throws IllegalAccessException
{
Class<?> []paramTypes = method.getParameterTypes();
int paramLen = paramTypes.length;
int resultOffset = findResultOffset(paramTypes);
method.setAccessible(true);
MethodHandle mh = MethodHandles.lookup().unreflect(method);
int []permute = new int[paramLen + 1];
permute[0] = 0;
for (int i = 0; i < resultOffset; i++) {
permute[i + 1] = i + 2;
}
for (int i = resultOffset + 1; i < paramLen; i++) {
permute[i + 1] = i + 1;
}
permute[resultOffset + 1] = 1;
MethodType type = MethodType.genericMethodType(paramLen + 1);
type = type.changeReturnType(void.class);
mh = mh.asType(type);
mh = filterMethod(ampManager,
mh,
method);
mh = MethodHandles.permuteArguments(mh, type, permute);
/*
if (paramLen > 0 && ! Object[].class.equals(paramTypes[paramLen - 1])) {
}
*/
mh = mh.asSpreader(Object[].class, paramLen - 1);
type = MethodType.methodType(void.class,
Object.class,
getResultClass(),
Object[].class);
return mh.asType(type);
}
private static MethodHandle constantBoolean(final Boolean value, final MethodType type) {
return MethodHandles.permuteArguments(MethodHandles.constant(Boolean.TYPE, value),
type.changeReturnType(Boolean.TYPE));
}
private static MethodHandle constantBoolean(Boolean value, MethodType type) {
return MethodHandles.permuteArguments(MethodHandles.constant(Boolean.TYPE, value),
type.changeReturnType(Boolean.TYPE));
}