Java example source code file (ValueConversions.java)
The ValueConversions.java Java example source code
/*
* Copyright (c) 2008, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package sun.invoke.util;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodHandles.Lookup;
import java.lang.invoke.MethodType;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.EnumMap;
import java.util.List;
public class ValueConversions {
private static final Class<?> THIS_CLASS = ValueConversions.class;
// Do not adjust this except for special platforms:
private static final int MAX_ARITY;
static {
final Object[] values = { 255 };
AccessController.doPrivileged(new PrivilegedAction<Void>() {
@Override
public Void run() {
values[0] = Integer.getInteger(THIS_CLASS.getName()+".MAX_ARITY", 255);
return null;
}
});
MAX_ARITY = (Integer) values[0];
}
private static final Lookup IMPL_LOOKUP = MethodHandles.lookup();
private static EnumMap<Wrapper, MethodHandle>[] newWrapperCaches(int n) {
@SuppressWarnings("unchecked") // generic array creation
EnumMap<Wrapper, MethodHandle>[] caches
= (EnumMap<Wrapper, MethodHandle>[]) new EnumMap[n];
for (int i = 0; i < n; i++)
caches[i] = new EnumMap<>(Wrapper.class);
return caches;
}
/// Converting references to values.
// There are several levels of this unboxing conversions:
// no conversions: exactly Integer.valueOf, etc.
// implicit conversions sanctioned by JLS 5.1.2, etc.
// explicit conversions as allowed by explicitCastArguments
static int unboxInteger(Object x, boolean cast) {
if (x instanceof Integer)
return ((Integer) x).intValue();
return primitiveConversion(Wrapper.INT, x, cast).intValue();
}
static byte unboxByte(Object x, boolean cast) {
if (x instanceof Byte)
return ((Byte) x).byteValue();
return primitiveConversion(Wrapper.BYTE, x, cast).byteValue();
}
static short unboxShort(Object x, boolean cast) {
if (x instanceof Short)
return ((Short) x).shortValue();
return primitiveConversion(Wrapper.SHORT, x, cast).shortValue();
}
static boolean unboxBoolean(Object x, boolean cast) {
if (x instanceof Boolean)
return ((Boolean) x).booleanValue();
return (primitiveConversion(Wrapper.BOOLEAN, x, cast).intValue() & 1) != 0;
}
static char unboxCharacter(Object x, boolean cast) {
if (x instanceof Character)
return ((Character) x).charValue();
return (char) primitiveConversion(Wrapper.CHAR, x, cast).intValue();
}
static long unboxLong(Object x, boolean cast) {
if (x instanceof Long)
return ((Long) x).longValue();
return primitiveConversion(Wrapper.LONG, x, cast).longValue();
}
static float unboxFloat(Object x, boolean cast) {
if (x instanceof Float)
return ((Float) x).floatValue();
return primitiveConversion(Wrapper.FLOAT, x, cast).floatValue();
}
static double unboxDouble(Object x, boolean cast) {
if (x instanceof Double)
return ((Double) x).doubleValue();
return primitiveConversion(Wrapper.DOUBLE, x, cast).doubleValue();
}
private static MethodType unboxType(Wrapper wrap) {
return MethodType.methodType(wrap.primitiveType(), Object.class, boolean.class);
}
private static final EnumMap<Wrapper, MethodHandle>[]
UNBOX_CONVERSIONS = newWrapperCaches(2);
private static MethodHandle unbox(Wrapper wrap, boolean cast) {
EnumMap<Wrapper, MethodHandle> cache = UNBOX_CONVERSIONS[(cast?1:0)];
MethodHandle mh = cache.get(wrap);
if (mh != null) {
return mh;
}
// slow path
switch (wrap) {
case OBJECT:
mh = IDENTITY; break;
case VOID:
mh = IGNORE; break;
}
if (mh != null) {
cache.put(wrap, mh);
return mh;
}
// look up the method
String name = "unbox" + wrap.wrapperSimpleName();
MethodType type = unboxType(wrap);
try {
mh = IMPL_LOOKUP.findStatic(THIS_CLASS, name, type);
} catch (ReflectiveOperationException ex) {
mh = null;
}
if (mh != null) {
mh = MethodHandles.insertArguments(mh, 1, cast);
cache.put(wrap, mh);
return mh;
}
throw new IllegalArgumentException("cannot find unbox adapter for " + wrap
+ (cast ? " (cast)" : ""));
}
public static MethodHandle unboxCast(Wrapper type) {
return unbox(type, true);
}
public static MethodHandle unbox(Class<?> type) {
return unbox(Wrapper.forPrimitiveType(type), false);
}
public static MethodHandle unboxCast(Class<?> type) {
return unbox(Wrapper.forPrimitiveType(type), true);
}
static private final Integer ZERO_INT = 0, ONE_INT = 1;
/// Primitive conversions
/**
* Produce a Number which represents the given value {@code x}
* according to the primitive type of the given wrapper {@code wrap}.
* Caller must invoke intValue, byteValue, longValue (etc.) on the result
* to retrieve the desired primitive value.
*/
public static Number primitiveConversion(Wrapper wrap, Object x, boolean cast) {
// Maybe merge this code with Wrapper.convert/cast.
Number res;
if (x == null) {
if (!cast) return null;
return ZERO_INT;
}
if (x instanceof Number) {
res = (Number) x;
} else if (x instanceof Boolean) {
res = ((boolean)x ? ONE_INT : ZERO_INT);
} else if (x instanceof Character) {
res = (int)(char)x;
} else {
// this will fail with the required ClassCastException:
res = (Number) x;
}
Wrapper xwrap = Wrapper.findWrapperType(x.getClass());
if (xwrap == null || !cast && !wrap.isConvertibleFrom(xwrap))
// this will fail with the required ClassCastException:
return (Number) wrap.wrapperType().cast(x);
return res;
}
/**
* The JVM verifier allows boolean, byte, short, or char to widen to int.
* Support exactly this conversion, from a boxed value type Boolean,
* Byte, Short, Character, or Integer.
*/
public static int widenSubword(Object x) {
if (x instanceof Integer)
return (int) x;
else if (x instanceof Boolean)
return fromBoolean((boolean) x);
else if (x instanceof Character)
return (char) x;
else if (x instanceof Short)
return (short) x;
else if (x instanceof Byte)
return (byte) x;
else
// Fail with a ClassCastException.
return (int) x;
}
/// Converting primitives to references
static Integer boxInteger(int x) {
return x;
}
static Byte boxByte(byte x) {
return x;
}
static Short boxShort(short x) {
return x;
}
static Boolean boxBoolean(boolean x) {
return x;
}
static Character boxCharacter(char x) {
return x;
}
static Long boxLong(long x) {
return x;
}
static Float boxFloat(float x) {
return x;
}
static Double boxDouble(double x) {
return x;
}
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 final EnumMap<Wrapper, MethodHandle>[]
BOX_CONVERSIONS = newWrapperCaches(2);
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 box(Class<?> type) {
boolean exact = false;
// e.g., boxShort(short)Short if exact,
// e.g., boxShort(short)Object if !exact
return box(Wrapper.forPrimitiveType(type), exact);
}
public static MethodHandle box(Wrapper type) {
boolean exact = false;
return box(type, exact);
}
/// Constant functions
static void ignore(Object x) {
// no value to return; this is an unbox of null
}
static void empty() {
}
static Object zeroObject() {
return null;
}
static int zeroInteger() {
return 0;
}
static long zeroLong() {
return 0;
}
static float zeroFloat() {
return 0;
}
static double zeroDouble() {
return 0;
}
private static final EnumMap<Wrapper, MethodHandle>[]
CONSTANT_FUNCTIONS = newWrapperCaches(2);
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);
}
/// Converting references to references.
/**
* Identity function.
* @param x an arbitrary reference value
* @return the same value x
*/
static <T> T identity(T x) {
return x;
}
static <T> T[] identity(T[] x) {
return x;
}
/**
* Identity function on ints.
* @param x an arbitrary int value
* @return the same value x
*/
static int identity(int x) {
return x;
}
static byte identity(byte x) {
return x;
}
static short identity(short x) {
return x;
}
static boolean identity(boolean x) {
return x;
}
static char identity(char x) {
return x;
}
/**
* Identity function on longs.
* @param x an arbitrary long value
* @return the same value x
*/
static long identity(long x) {
return x;
}
static float identity(float x) {
return x;
}
static double identity(double x) {
return x;
}
/**
* Identity function, with reference cast.
* @param t an arbitrary reference type
* @param x an arbitrary reference value
* @return the same value x
*/
@SuppressWarnings("unchecked")
static <T,U> T castReference(Class t, U x) {
// inlined Class.cast because we can't ForceInline it
if (x != null && !t.isInstance(x))
throw newClassCastException(t, x);
return (T) x;
}
private static ClassCastException newClassCastException(Class<?> t, Object obj) {
return new ClassCastException("Cannot cast " + obj.getClass().getName() + " to " + t.getName());
}
private static final MethodHandle IDENTITY, CAST_REFERENCE, ZERO_OBJECT, IGNORE, EMPTY,
ARRAY_IDENTITY, FILL_NEW_TYPED_ARRAY, FILL_NEW_ARRAY;
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);
}
}
// Varargs methods need to be in a separately initialized class, to avoid bootstrapping problems.
static class LazyStatics {
private static final MethodHandle COPY_AS_REFERENCE_ARRAY, COPY_AS_PRIMITIVE_ARRAY, MAKE_LIST;
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 final EnumMap<Wrapper, MethodHandle>[] WRAPPER_CASTS
= newWrapperCaches(1);
/** Return a method that casts its sole argument (an Object) to the given type
* and returns it as the given type.
*/
public static MethodHandle cast(Class<?> type) {
if (type.isPrimitive()) throw new IllegalArgumentException("cannot cast primitive type "+type);
MethodHandle mh;
Wrapper wrap = null;
EnumMap<Wrapper, MethodHandle> cache = null;
if (Wrapper.isWrapperType(type)) {
wrap = Wrapper.forWrapperType(type);
cache = WRAPPER_CASTS[0];
mh = cache.get(wrap);
if (mh != null) return mh;
}
mh = MethodHandles.insertArguments(CAST_REFERENCE, 0, type);
if (cache != null)
cache.put(wrap, mh);
return mh;
}
public static MethodHandle identity() {
return IDENTITY;
}
public static MethodHandle identity(Class<?> type) {
if (!type.isPrimitive())
// Reference identity has been moved into MethodHandles:
return MethodHandles.identity(type);
return identity(Wrapper.findPrimitiveType(type));
}
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);
}
/// Primitive conversions.
// These are supported directly by the JVM, usually by a single instruction.
// In the case of narrowing to a subword, there may be a pair of instructions.
// In the case of booleans, there may be a helper routine to manage a 1-bit value.
// This is the full 8x8 matrix (minus the diagonal).
// narrow double to all other types:
static float doubleToFloat(double x) { // bytecode: d2f
return (float) x;
}
static long doubleToLong(double x) { // bytecode: d2l
return (long) x;
}
static int doubleToInt(double x) { // bytecode: d2i
return (int) x;
}
static short doubleToShort(double x) { // bytecodes: d2i, i2s
return (short) x;
}
static char doubleToChar(double x) { // bytecodes: d2i, i2c
return (char) x;
}
static byte doubleToByte(double x) { // bytecodes: d2i, i2b
return (byte) x;
}
static boolean doubleToBoolean(double x) {
return toBoolean((byte) x);
}
// widen float:
static double floatToDouble(float x) { // bytecode: f2d
return x;
}
// narrow float:
static long floatToLong(float x) { // bytecode: f2l
return (long) x;
}
static int floatToInt(float x) { // bytecode: f2i
return (int) x;
}
static short floatToShort(float x) { // bytecodes: f2i, i2s
return (short) x;
}
static char floatToChar(float x) { // bytecodes: f2i, i2c
return (char) x;
}
static byte floatToByte(float x) { // bytecodes: f2i, i2b
return (byte) x;
}
static boolean floatToBoolean(float x) {
return toBoolean((byte) x);
}
// widen long:
static double longToDouble(long x) { // bytecode: l2d
return x;
}
static float longToFloat(long x) { // bytecode: l2f
return x;
}
// narrow long:
static int longToInt(long x) { // bytecode: l2i
return (int) x;
}
static short longToShort(long x) { // bytecodes: f2i, i2s
return (short) x;
}
static char longToChar(long x) { // bytecodes: f2i, i2c
return (char) x;
}
static byte longToByte(long x) { // bytecodes: f2i, i2b
return (byte) x;
}
static boolean longToBoolean(long x) {
return toBoolean((byte) x);
}
// widen int:
static double intToDouble(int x) { // bytecode: i2d
return x;
}
static float intToFloat(int x) { // bytecode: i2f
return x;
}
static long intToLong(int x) { // bytecode: i2l
return x;
}
// narrow int:
static short intToShort(int x) { // bytecode: i2s
return (short) x;
}
static char intToChar(int x) { // bytecode: i2c
return (char) x;
}
static byte intToByte(int x) { // bytecode: i2b
return (byte) x;
}
static boolean intToBoolean(int x) {
return toBoolean((byte) x);
}
// widen short:
static double shortToDouble(short x) { // bytecode: i2d (implicit 's2i')
return x;
}
static float shortToFloat(short x) { // bytecode: i2f (implicit 's2i')
return x;
}
static long shortToLong(short x) { // bytecode: i2l (implicit 's2i')
return x;
}
static int shortToInt(short x) { // (implicit 's2i')
return x;
}
// narrow short:
static char shortToChar(short x) { // bytecode: i2c (implicit 's2i')
return (char)x;
}
static byte shortToByte(short x) { // bytecode: i2b (implicit 's2i')
return (byte)x;
}
static boolean shortToBoolean(short x) {
return toBoolean((byte) x);
}
// widen char:
static double charToDouble(char x) { // bytecode: i2d (implicit 'c2i')
return x;
}
static float charToFloat(char x) { // bytecode: i2f (implicit 'c2i')
return x;
}
static long charToLong(char x) { // bytecode: i2l (implicit 'c2i')
return x;
}
static int charToInt(char x) { // (implicit 'c2i')
return x;
}
// narrow char:
static short charToShort(char x) { // bytecode: i2s (implicit 'c2i')
return (short)x;
}
static byte charToByte(char x) { // bytecode: i2b (implicit 'c2i')
return (byte)x;
}
static boolean charToBoolean(char x) {
return toBoolean((byte) x);
}
// widen byte:
static double byteToDouble(byte x) { // bytecode: i2d (implicit 'b2i')
return x;
}
static float byteToFloat(byte x) { // bytecode: i2f (implicit 'b2i')
return x;
}
static long byteToLong(byte x) { // bytecode: i2l (implicit 'b2i')
return x;
}
static int byteToInt(byte x) { // (implicit 'b2i')
return x;
}
static short byteToShort(byte x) { // bytecode: i2s (implicit 'b2i')
return (short)x;
}
static char byteToChar(byte x) { // bytecode: i2b (implicit 'b2i')
return (char)x;
}
// narrow byte to boolean:
static boolean byteToBoolean(byte x) {
return toBoolean(x);
}
// widen boolean to all types:
static double booleanToDouble(boolean x) {
return fromBoolean(x);
}
static float booleanToFloat(boolean x) {
return fromBoolean(x);
}
static long booleanToLong(boolean x) {
return fromBoolean(x);
}
static int booleanToInt(boolean x) {
return fromBoolean(x);
}
static short booleanToShort(boolean x) {
return fromBoolean(x);
}
static char booleanToChar(boolean x) {
return (char)fromBoolean(x);
}
static byte booleanToByte(boolean x) {
return fromBoolean(x);
}
// helpers to force boolean into the conversion scheme:
static boolean toBoolean(byte x) {
// see javadoc for MethodHandles.explicitCastArguments
return ((x & 1) != 0);
}
static byte fromBoolean(boolean x) {
// see javadoc for MethodHandles.explicitCastArguments
return (x ? (byte)1 : (byte)0);
}
private static final EnumMap<Wrapper, MethodHandle>[]
CONVERT_PRIMITIVE_FUNCTIONS = newWrapperCaches(Wrapper.values().length);
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());
}
public static MethodHandle convertPrimitive(Class<?> src, Class dst) {
return convertPrimitive(Wrapper.forPrimitiveType(src), Wrapper.forPrimitiveType(dst));
}
private static String capitalize(String x) {
return Character.toUpperCase(x.charAt(0))+x.substring(1);
}
/// Collection of multiple arguments.
public static Object convertArrayElements(Class<?> arrayType, Object array) {
Class<?> src = array.getClass().getComponentType();
Class<?> dst = arrayType.getComponentType();
if (src == null || dst == null) throw new IllegalArgumentException("not array type");
Wrapper sw = (src.isPrimitive() ? Wrapper.forPrimitiveType(src) : null);
Wrapper dw = (dst.isPrimitive() ? Wrapper.forPrimitiveType(dst) : null);
int length;
if (sw == null) {
Object[] a = (Object[]) array;
length = a.length;
if (dw == null)
return Arrays.copyOf(a, length, arrayType.asSubclass(Object[].class));
Object res = dw.makeArray(length);
dw.copyArrayUnboxing(a, 0, res, 0, length);
return res;
}
length = java.lang.reflect.Array.getLength(array);
Object[] res;
if (dw == null) {
res = Arrays.copyOf(NO_ARGS_ARRAY, length, arrayType.asSubclass(Object[].class));
} else {
res = new Object[length];
}
sw.copyArrayBoxing(array, 0, res, 0, length);
if (dw == null) return res;
Object a = dw.makeArray(length);
dw.copyArrayUnboxing(res, 0, a, 0, length);
return a;
}
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;
}
}
private static final Object[] NO_ARGS_ARRAY = {};
private static Object[] makeArray(Object... args) { return args; }
private static Object[] array() { return NO_ARGS_ARRAY; }
private static Object[] array(Object a0)
{ return makeArray(a0); }
private static Object[] array(Object a0, Object a1)
{ return makeArray(a0, a1); }
private static Object[] array(Object a0, Object a1, Object a2)
{ return makeArray(a0, a1, a2); }
private static Object[] array(Object a0, Object a1, Object a2, Object a3)
{ return makeArray(a0, a1, a2, a3); }
private static Object[] array(Object a0, Object a1, Object a2, Object a3,
Object a4)
{ return makeArray(a0, a1, a2, a3, a4); }
private static Object[] array(Object a0, Object a1, Object a2, Object a3,
Object a4, Object a5)
{ return makeArray(a0, a1, a2, a3, a4, a5); }
private static Object[] array(Object a0, Object a1, Object a2, Object a3,
Object a4, Object a5, Object a6)
{ return makeArray(a0, a1, a2, a3, a4, a5, a6); }
private static Object[] array(Object a0, Object a1, Object a2, Object a3,
Object a4, Object a5, Object a6, Object a7)
{ return makeArray(a0, a1, a2, a3, a4, a5, a6, a7); }
private static Object[] array(Object a0, Object a1, Object a2, Object a3,
Object a4, Object a5, Object a6, Object a7,
Object a8)
{ return makeArray(a0, a1, a2, a3, a4, a5, a6, a7, a8); }
private static Object[] array(Object a0, Object a1, Object a2, Object a3,
Object a4, Object a5, Object a6, Object a7,
Object a8, Object a9)
{ return makeArray(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); }
private static MethodHandle[] makeArrays() {
ArrayList<MethodHandle> mhs = new ArrayList<>();
for (;;) {
MethodHandle mh = findCollector("array", mhs.size(), Object[].class);
if (mh == null) break;
mhs.add(mh);
}
assert(mhs.size() == 11); // current number of methods
return mhs.toArray(new MethodHandle[MAX_ARITY+1]);
}
private static final MethodHandle[] ARRAYS = makeArrays();
// filling versions of the above:
// using Integer len instead of int len and no varargs to avoid bootstrapping problems
private static Object[] fillNewArray(Integer len, Object[] /*not ...*/ args) {
Object[] a = new Object[len];
fillWithArguments(a, 0, args);
return a;
}
private static Object[] fillNewTypedArray(Object[] example, Integer len, Object[] /*not ...*/ args) {
Object[] a = Arrays.copyOf(example, len);
fillWithArguments(a, 0, args);
return a;
}
private static void fillWithArguments(Object[] a, int pos, Object... args) {
System.arraycopy(args, 0, a, pos, args.length);
}
// using Integer pos instead of int pos to avoid bootstrapping problems
private static Object[] fillArray(Integer pos, Object[] a, Object a0)
{ fillWithArguments(a, pos, a0); return a; }
private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1)
{ fillWithArguments(a, pos, a0, a1); return a; }
private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2)
{ fillWithArguments(a, pos, a0, a1, a2); return a; }
private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3)
{ fillWithArguments(a, pos, a0, a1, a2, a3); return a; }
private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
Object a4)
{ fillWithArguments(a, pos, a0, a1, a2, a3, a4); return a; }
private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
Object a4, Object a5)
{ fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5); return a; }
private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
Object a4, Object a5, Object a6)
{ fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6); return a; }
private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
Object a4, Object a5, Object a6, Object a7)
{ fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7); return a; }
private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
Object a4, Object a5, Object a6, Object a7,
Object a8)
{ fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7, a8); return a; }
private static Object[] fillArray(Integer pos, Object[] a, Object a0, Object a1, Object a2, Object a3,
Object a4, Object a5, Object a6, Object a7,
Object a8, Object a9)
{ fillWithArguments(a, pos, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); return a; }
private static MethodHandle[] makeFillArrays() {
ArrayList<MethodHandle> mhs = new ArrayList<>();
mhs.add(null); // there is no empty fill; at least a0 is required
for (;;) {
MethodHandle mh = findCollector("fillArray", mhs.size(), Object[].class, Integer.class, Object[].class);
if (mh == null) break;
mhs.add(mh);
}
assert(mhs.size() == 11); // current number of methods
return mhs.toArray(new MethodHandle[0]);
}
private static final MethodHandle[] FILL_ARRAYS = makeFillArrays();
private static Object[] copyAsReferenceArray(Class<? extends Object[]> arrayType, Object... a) {
return Arrays.copyOf(a, a.length, arrayType);
}
private static Object copyAsPrimitiveArray(Wrapper w, Object... boxes) {
Object a = w.makeArray(boxes.length);
w.copyArrayUnboxing(boxes, 0, a, 0, boxes.length);
return a;
}
/** Return a method handle that takes the indicated number of Object
* arguments and returns an Object array of them, as if for varargs.
*/
public static MethodHandle varargsArray(int nargs) {
MethodHandle mh = ARRAYS[nargs];
if (mh != null) return mh;
mh = findCollector("array", nargs, Object[].class);
if (mh != null) return ARRAYS[nargs] = mh;
mh = buildVarargsArray(FILL_NEW_ARRAY, ARRAY_IDENTITY, nargs);
assert(assertCorrectArity(mh, nargs));
return ARRAYS[nargs] = mh;
}
private static boolean assertCorrectArity(MethodHandle mh, int arity) {
assert(mh.type().parameterCount() == arity) : "arity != "+arity+": "+mh;
return true;
}
private static MethodHandle buildVarargsArray(MethodHandle newArray, MethodHandle finisher, int nargs) {
// Build up the result mh as a sequence of fills like this:
// finisher(fill(fill(newArrayWA(23,x1..x10),10,x11..x20),20,x21..x23))
// The various fill(_,10*I,___*[J]) are reusable.
int leftLen = Math.min(nargs, LEFT_ARGS); // absorb some arguments immediately
int rightLen = nargs - leftLen;
MethodHandle leftCollector = newArray.bindTo(nargs);
leftCollector = leftCollector.asCollector(Object[].class, leftLen);
MethodHandle mh = finisher;
if (rightLen > 0) {
MethodHandle rightFiller = fillToRight(LEFT_ARGS + rightLen);
if (mh == ARRAY_IDENTITY)
mh = rightFiller;
else
mh = MethodHandles.collectArguments(mh, 0, rightFiller);
}
if (mh == ARRAY_IDENTITY)
mh = leftCollector;
else
mh = MethodHandles.collectArguments(mh, 0, leftCollector);
return mh;
}
private static final int LEFT_ARGS = (FILL_ARRAYS.length - 1);
private static final MethodHandle[] FILL_ARRAY_TO_RIGHT = new MethodHandle[MAX_ARITY+1];
/** fill_array_to_right(N).invoke(a, argL..arg[N-1])
* fills a[L]..a[N-1] with corresponding arguments,
* and then returns a. The value L is a global constant (LEFT_ARGS).
*/
private static MethodHandle fillToRight(int nargs) {
MethodHandle filler = FILL_ARRAY_TO_RIGHT[nargs];
if (filler != null) return filler;
filler = buildFiller(nargs);
assert(assertCorrectArity(filler, nargs - LEFT_ARGS + 1));
return FILL_ARRAY_TO_RIGHT[nargs] = filler;
}
private static MethodHandle buildFiller(int nargs) {
if (nargs <= LEFT_ARGS)
return ARRAY_IDENTITY; // no args to fill; return the array unchanged
// we need room for both mh and a in mh.invoke(a, arg*[nargs])
final int CHUNK = LEFT_ARGS;
int rightLen = nargs % CHUNK;
int midLen = nargs - rightLen;
if (rightLen == 0) {
midLen = nargs - (rightLen = CHUNK);
if (FILL_ARRAY_TO_RIGHT[midLen] == null) {
// build some precursors from left to right
for (int j = LEFT_ARGS % CHUNK; j < midLen; j += CHUNK)
if (j > LEFT_ARGS) fillToRight(j);
}
}
if (midLen < LEFT_ARGS) rightLen = nargs - (midLen = LEFT_ARGS);
assert(rightLen > 0);
MethodHandle midFill = fillToRight(midLen); // recursive fill
MethodHandle rightFill = FILL_ARRAYS[rightLen].bindTo(midLen); // [midLen..nargs-1]
assert(midFill.type().parameterCount() == 1 + midLen - LEFT_ARGS);
assert(rightFill.type().parameterCount() == 1 + rightLen);
// Combine the two fills:
// right(mid(a, x10..x19), x20..x23)
// The final product will look like this:
// right(mid(newArrayLeft(24, x0..x9), x10..x19), x20..x23)
if (midLen == LEFT_ARGS)
return rightFill;
else
return MethodHandles.collectArguments(rightFill, 0, midFill);
}
// Type-polymorphic version of varargs maker.
private static final ClassValue<MethodHandle[]> TYPED_COLLECTORS
= new ClassValue<MethodHandle[]>() {
@Override
protected MethodHandle[] computeValue(Class<?> type) {
return new MethodHandle[256];
}
};
static final int MAX_JVM_ARITY = 255; // limit imposed by the JVM
/** 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) 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.<ClassnCopies(nargs, elemType)));
assert(assertCorrectArity(mh, nargs));
if (nargs < cache.length)
cache[nargs] = mh;
return mh;
}
private static MethodHandle buildArrayProducer(Class<?> arrayType) {
Class<?> elemType = arrayType.getComponentType();
if (elemType.isPrimitive())
return LazyStatics.COPY_AS_PRIMITIVE_ARRAY.bindTo(Wrapper.forPrimitiveType(elemType));
else
return LazyStatics.COPY_AS_REFERENCE_ARRAY.bindTo(arrayType);
}
// List version of varargs maker.
private static final List<Object> NO_ARGS_LIST = Arrays.asList(NO_ARGS_ARRAY);
private static List<Object> makeList(Object... args) { return Arrays.asList(args); }
private static List<Object> list() { return NO_ARGS_LIST; }
private static List<Object> list(Object a0)
{ return makeList(a0); }
private static List<Object> list(Object a0, Object a1)
{ return makeList(a0, a1); }
private static List<Object> list(Object a0, Object a1, Object a2)
{ return makeList(a0, a1, a2); }
private static List<Object> list(Object a0, Object a1, Object a2, Object a3)
{ return makeList(a0, a1, a2, a3); }
private static List<Object> list(Object a0, Object a1, Object a2, Object a3,
Object a4)
{ return makeList(a0, a1, a2, a3, a4); }
private static List<Object> list(Object a0, Object a1, Object a2, Object a3,
Object a4, Object a5)
{ return makeList(a0, a1, a2, a3, a4, a5); }
private static List<Object> list(Object a0, Object a1, Object a2, Object a3,
Object a4, Object a5, Object a6)
{ return makeList(a0, a1, a2, a3, a4, a5, a6); }
private static List<Object> list(Object a0, Object a1, Object a2, Object a3,
Object a4, Object a5, Object a6, Object a7)
{ return makeList(a0, a1, a2, a3, a4, a5, a6, a7); }
private static List<Object> list(Object a0, Object a1, Object a2, Object a3,
Object a4, Object a5, Object a6, Object a7,
Object a8)
{ return makeList(a0, a1, a2, a3, a4, a5, a6, a7, a8); }
private static List<Object> list(Object a0, Object a1, Object a2, Object a3,
Object a4, Object a5, Object a6, Object a7,
Object a8, Object a9)
{ return makeList(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9); }
private static MethodHandle[] makeLists() {
ArrayList<MethodHandle> mhs = new ArrayList<>();
for (;;) {
MethodHandle mh = findCollector("list", mhs.size(), List.class);
if (mh == null) break;
mhs.add(mh);
}
assert(mhs.size() == 11); // current number of methods
return mhs.toArray(new MethodHandle[MAX_ARITY+1]);
}
private static final MethodHandle[] LISTS = makeLists();
/** Return a method handle that takes the indicated number of Object
* arguments and returns a List.
*/
public static MethodHandle varargsList(int nargs) {
MethodHandle mh = LISTS[nargs];
if (mh != null) return mh;
mh = findCollector("list", nargs, List.class);
if (mh != null) return LISTS[nargs] = mh;
return LISTS[nargs] = buildVarargsList(nargs);
}
private static MethodHandle buildVarargsList(int nargs) {
return MethodHandles.filterReturnValue(varargsArray(nargs), LazyStatics.MAKE_LIST);
}
// handy shared exception makers (they simplify the common case code)
private static InternalError newInternalError(String message, Throwable cause) {
return new InternalError(message, cause);
}
private static InternalError newInternalError(Throwable cause) {
return new InternalError(cause);
}
}
Other Java examples (source code examples)Here is a short list of links related to this Java ValueConversions.java source code file: |
The search page
Other Java source code examples at this package level
Click here to learn more about this project
