java.lang.invoke.MethodType Java Examples

@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");
}
 

public CatchExceptionTest(TestCase testCase, final boolean isVararg, final int argsCount,
        final int catchDrops) {
    this.testCase = testCase;
    this.dropped = catchDrops;
    MethodHandle thrower = testCase.thrower;
    int throwerLen = thrower.type().parameterCount();
    List<Class<?>> classes;
    int extra = Math.max(0, argsCount - throwerLen);
    classes = getThrowerParams(isVararg, extra);
    this.argsCount = throwerLen + classes.size();
    thrower = Helper.addTrailingArgs(thrower, this.argsCount, classes);
    if (isVararg && argsCount > throwerLen) {
        MethodType mt = thrower.type();
        Class<?> lastParam = mt.parameterType(mt.parameterCount() - 1);
        thrower = thrower.asVarargsCollector(lastParam);
    }
    this.thrower = thrower;
    this.dropped = Math.min(this.argsCount, catchDrops);
    catcher = testCase.getCatcher(getCatcherParams());
    nargs = Math.max(2, this.argsCount);
}
 

@Override
CompiledFunction getBest(final MethodType callSiteType, final ScriptObject runtimeScope, final Collection<CompiledFunction> forbidden, boolean linkLogicOkay) {
    assert isValidCallSite(callSiteType) : callSiteType;

    CompiledFunction best = null;
    for (final CompiledFunction candidate: code) {
        if (!linkLogicOkay && candidate.hasLinkLogic()) {
            // Skip! Version with no link logic is desired, but this one has link logic!
            continue;
        }

        if (!forbidden.contains(candidate) && candidate.betterThanFinal(best, callSiteType)) {
            best = candidate;
        }
    }

    return best;
}
 

/**
 * Test of toString method, of class MethodType.
 */
@Test
public void testToString() {
    System.out.println("toString");
    MethodType[] instances = {mt_viS, mt_OO2, mt_vv, mt_Ov, mt_iSI, mt_ISi, mt_ISI, mt_iSi};
    //String expResult = "void[int, class java.lang.String]";
    String[] expResults = {
        "(int,String)void",
        "(Object,Object)Object",
        "()void",
        "()Object",
        "(String,Integer)int",
        "(String,int)Integer",
        "(String,Integer)Integer",
        "(String,int)int"
    };
    for (int i = 0; i < instances.length; i++) {
        MethodType instance = instances[i];
        String result = instance.toString();
        System.out.println("#"+i+":"+result);
        assertEquals("#"+i, expResults[i], result);
    }
}
 

public static void main(String[] args) throws Throwable {
    l = MethodHandles.lookup();
    h = l.findVirtual(LambdaReceiver_A.class, "f", mt(int.class));
    MethodType X = mt(int.class, LambdaReceiver.class);
    MethodType A = mt(int.class, LambdaReceiver_A.class);
    MethodType mti = mt(IA.class);
    CallSite cs = LambdaMetafactory.metafactory(l, "m", mti,A,h,X);
    IA p = (IA)cs.dynamicInvoker().invoke();
    LambdaReceiver_A lra = new LambdaReceiver_A();
    try {
        p.m(lra);
    } catch (ClassCastException cce) {
        return;
    }
    throw new AssertionError("CCE expected");
}
 

/**
 * Produces a {@link MethodHandle} or {@link MethodType} using {@link #targetLoader} for the
 * given ASM {@link Handle} or {@link Type}. {@code lookup} is only used for resolving {@link
 * Handle}s.
 */
private Object toJvmMetatype(Lookup lookup, Object asm) throws ReflectiveOperationException {
  if (asm instanceof Number) {
    return asm;
  }
  if (asm instanceof Type) {
    Type type = (Type) asm;
    switch (type.getSort()) {
      case Type.OBJECT:
        return loadFromInternal(type.getInternalName());
      case Type.METHOD:
        return MethodType.fromMethodDescriptorString(type.getDescriptor(), targetLoader);
      default:
        throw new IllegalArgumentException("Cannot convert: " + asm);
    }
  }
  if (asm instanceof Handle) {
    return toMethodHandle(lookup, (Handle) asm, /*target*/ true);
  }
  throw new IllegalArgumentException("Cannot convert: " + asm);
}
 

private static MethodType createLambdaMethodType(Method method, MethodType instantiatedMethodType) {
	boolean isStatic = Modifier.isStatic(method.getModifiers());
	MethodType signature = isStatic ? instantiatedMethodType : instantiatedMethodType.changeParameterType(0, Object.class);

	Class<?>[] params = method.getParameterTypes();
	for (int i=0; i<params.length; i++){
		if (Object.class.isAssignableFrom(params[i])){
			signature = signature.changeParameterType(isStatic ? i : i+1, Object.class);
		}
	}
	if (Object.class.isAssignableFrom(signature.returnType())){
		signature = signature.changeReturnType(Object.class);
	}
	
	return signature;
}
 

Compiler getCompiler(final FunctionNode functionNode, final MethodType actualCallSiteType,
        final ScriptObject runtimeScope, final Map<Integer, Type> invalidatedProgramPoints,
        final int[] continuationEntryPoints) {
    final TypeMap typeMap = typeMap(actualCallSiteType);
    final Type[] paramTypes = typeMap == null ? null : typeMap.getParameterTypes(functionNodeId);
    final Object typeInformationFile = OptimisticTypesPersistence.getLocationDescriptor(source, functionNodeId, paramTypes);
    final Context context = Context.getContextTrusted();
    return new Compiler(
            context,
            context.getEnv(),
            getInstallerForNewCode(),
            functionNode.getSource(),  // source
            context.getErrorManager(),
            isStrict() | functionNode.isStrict(), // is strict
            true,       // is on demand
            this,       // compiledFunction, i.e. this RecompilableScriptFunctionData
            typeMap,    // type map
            getEffectiveInvalidatedProgramPoints(invalidatedProgramPoints, typeInformationFile), // invalidated program points
            typeInformationFile,
            continuationEntryPoints, // continuation entry points
            runtimeScope); // runtime scope
}
 

@Test(dataProvider = "flags")
public void systemLoadLibraryTest(final boolean publicLookup) {
    final CallSite cs1 = createGetMethodCallSite(publicLookup, "loadLibrary");
    final CallSite cs2 = createCallSite(publicLookup, CALL, MethodType.methodType(void.class, Object.class, Object.class, String.class));

    try {
        final Object method = cs1.getTarget().invoke(StaticClass.forClass(System.class));
        cs2.getTarget().invoke(method, StaticClass.forClass(System.class), "foo");
        throw new RuntimeException("should not reach here in any case!");
    } catch (final Throwable th) {
        if (publicLookup) {
            Assert.assertTrue(th instanceof IllegalAccessError);
        } else {
            Assert.assertTrue(th instanceof AccessControlException);
        }
    }
}
 

@Override
CompiledFunction getBest(final MethodType callSiteType, final ScriptObject runtimeScope, final Collection<CompiledFunction> forbidden, boolean linkLogicOkay) {
    assert isValidCallSite(callSiteType) : callSiteType;

    CompiledFunction best = null;
    for (final CompiledFunction candidate: code) {
        if (!linkLogicOkay && candidate.hasLinkLogic()) {
            // Skip! Version with no link logic is desired, but this one has link logic!
            continue;
        }

        if (!forbidden.contains(candidate) && candidate.betterThanFinal(best, callSiteType)) {
            best = candidate;
        }
    }

    return best;
}
 

MethodHandle createConverter(final Class<?> sourceType, final Class<?> targetType) throws Exception {
    final MethodType type = MethodType.methodType(targetType, sourceType);
    final MethodHandle identity = IDENTITY_CONVERSION.asType(type);
    MethodHandle last = identity;
    boolean cacheable = true;
    for(int i = factories.length; i-- > 0;) {
        final GuardedTypeConversion next = factories[i].convertToType(sourceType, targetType);
        if(next != null) {
            cacheable = cacheable && next.isCacheable();
            final GuardedInvocation conversionInvocation = next.getConversionInvocation();
            conversionInvocation.assertType(type);
            last = conversionInvocation.compose(last);
        }
    }
    if(last == identity) {
        return IDENTITY_CONVERSION;
    }
    if(cacheable) {
        return last;
    }
    throw new NotCacheableConverter(last);
}
 

public static void main(String[] args) throws Throwable {
    l = MethodHandles.lookup();
    h = l.findVirtual(LambdaReceiver_A.class, "f", mt(int.class));
    MethodType X = mt(int.class, LambdaReceiver.class);
    MethodType A = mt(int.class, LambdaReceiver_A.class);
    MethodType mti = mt(IA.class);
    CallSite cs = LambdaMetafactory.metafactory(l, "m", mti,A,h,X);
    IA p = (IA)cs.dynamicInvoker().invoke();
    LambdaReceiver_A lra = new LambdaReceiver_A();
    try {
        p.m(lra);
    } catch (ClassCastException cce) {
        return;
    }
    throw new AssertionError("CCE expected");
}
 

private MethodHandle introspectConstructor()
{
  try {
    Method m = _type.getMethod("valueOf", String.class);
    
    Objects.requireNonNull(m);
    
    m.setAccessible(true);
      
    MethodHandle mh = MethodHandles.lookup().unreflect(m);
        
    mh = mh.asType(MethodType.methodType(Object.class, String.class));
      
    return mh;
  } catch (Exception e) {
    throw new H3ExceptionIn(_type.getName() + ": " + e.getMessage(), e);
  }
}
 

private static MethodHandle spreadGuardArguments(final MethodHandle guard, final MethodType descType) {
    final MethodType guardType = guard.type();
    final int guardParamCount = guardType.parameterCount();
    final int descParamCount = descType.parameterCount();
    final int spreadCount = guardParamCount - descParamCount + 1;
    if (spreadCount <= 0) {
        // Guard doesn't dip into the varargs
        return guard;
    }

    final MethodHandle arrayConvertingGuard;
    // If the last parameter type of the guard is an array, then it is already itself a guard for a vararg apply
    // invocation. We must filter the last argument with toApplyArgs otherwise deeper levels of nesting will fail
    // with ClassCastException of NativeArray to Object[].
    if (guardType.parameterType(guardParamCount - 1).isArray()) {
        arrayConvertingGuard = MH.filterArguments(guard, guardParamCount - 1, NativeFunction.TO_APPLY_ARGS);
    } else {
        arrayConvertingGuard = guard;
    }

    return ScriptObject.adaptHandleToVarArgCallSite(arrayConvertingGuard, descParamCount);
}
 

private static GuardedInvocation fixExpressionCallSite(final NashornCallSiteDescriptor desc, final GuardedInvocation link) {
    // If it's not a getMethod, just add an expression filter that converts WithObject in "this" position to its
    // expression.
    if(!"getMethod".equals(desc.getFirstOperator())) {
        return fixReceiverType(link, WITHEXPRESSIONFILTER).filterArguments(0, WITHEXPRESSIONFILTER);
    }

    final MethodHandle linkInvocation = link.getInvocation();
    final MethodType linkType = linkInvocation.type();
    final boolean linkReturnsFunction = ScriptFunction.class.isAssignableFrom(linkType.returnType());
    return link.replaceMethods(
            // Make sure getMethod will bind the script functions it receives to WithObject.expression
            MH.foldArguments(linkReturnsFunction ? BIND_TO_EXPRESSION_FN : BIND_TO_EXPRESSION_OBJ,
                    filter(linkInvocation.asType(linkType.changeReturnType(
                            linkReturnsFunction ? ScriptFunction.class : Object.class)), WITHEXPRESSIONFILTER)),
            // No clever things for the guard -- it is still identically filtered.
            filterGuard(link, WITHEXPRESSIONFILTER));
}
 

/**
 * Find an implementation for a "dyn:callMethod" operation. Note that Nashorn internally never uses
 * "dyn:callMethod", but instead always emits two call sites in bytecode, one for "dyn:getMethod", and then another
 * one for "dyn:call". Explicit support for "dyn:callMethod" is provided for the benefit of potential external
 * callers. The implementation itself actually folds a "dyn:getMethod" method handle into a "dyn:call" method handle.
 *
 * @param desc    the call site descriptor.
 * @param request the link request
 *
 * @return GuardedInvocation to be invoked at call site.
 */
protected GuardedInvocation findCallMethodMethod(final CallSiteDescriptor desc, final LinkRequest request) {
    // R(P0, P1, ...)
    final MethodType callType = desc.getMethodType();
    // use type Object(P0) for the getter
    final CallSiteDescriptor getterType = desc.changeMethodType(MethodType.methodType(Object.class, callType.parameterType(0)));
    final GuardedInvocation getter = findGetMethod(getterType, request, "getMethod");

    // Object(P0) => Object(P0, P1, ...)
    final MethodHandle argDroppingGetter = MH.dropArguments(getter.getInvocation(), 1, callType.parameterList().subList(1, callType.parameterCount()));
    // R(Object, P0, P1, ...)
    final MethodHandle invoker = Bootstrap.createDynamicInvoker("dyn:call", callType.insertParameterTypes(0, argDroppingGetter.type().returnType()));
    // Fold Object(P0, P1, ...) into R(Object, P0, P1, ...) => R(P0, P1, ...)
    return getter.replaceMethods(MH.foldArguments(invoker, argDroppingGetter), getter.getGuard());
}
 

private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) {
    final Class<?>   own = ScriptFunction.class;
    final MethodType mt  = MH.type(rtype, types);
    try {
        return MH.findStatic(MethodHandles.lookup(), own, name, mt);
    } catch (final MethodHandleFactory.LookupException e) {
        return MH.findVirtual(MethodHandles.lookup(), own, name, mt);
    }
}
 

private static MethodHandle getBeanOperation(final GuardingDynamicLinker linker, final String operation,
        final MethodType methodType, final Object source) {
    final GuardedInvocation inv;
    try {
        inv = NashornBeansLinker.getGuardedInvocation(linker, createLinkRequest(operation, methodType, source), Bootstrap.getLinkerServices());
        assert passesGuard(source, inv.getGuard());
    } catch(RuntimeException|Error e) {
        throw e;
    } catch(final Throwable t) {
        throw new RuntimeException(t);
    }
    assert inv.getSwitchPoints() == null; // Linkers in Dynalink's beans package don't use switchpoints.
    // We discard the guard, as all method handles will be bound to a specific object.
    return inv.getInvocation();
}
 

public void testDirectStdSer() throws Throwable {
    MethodHandle fooMH = MethodHandles.lookup().findStatic(SerializedLambdaTest.class, "foo", predicateMT);

    // Standard metafactory, serializable target: not serializable
    CallSite cs = LambdaMetafactory.metafactory(MethodHandles.lookup(),
                                                "test", MethodType.methodType(SerPredicate.class),
                                                predicateMT, fooMH, stringPredicateMT);
    assertNotSerial((SerPredicate<String>) cs.getTarget().invokeExact(), fooAsserter);
}
 

/**
 * Creates a method handle that returns true if the argument in the specified position is a Java array.
 *
 * @param pos the position in the argument lit
 * @param type the method type of the handle
 * @return a method handle that returns true if the argument in the specified position is a Java array; the rest of
 * the arguments are ignored.
 */
@SuppressWarnings("boxing")
public static MethodHandle isArray(int pos, MethodType type) {
    final Class<?> declaredType = type.parameterType(pos);
    if(declaredType.isArray()) {
        LOG.log(Level.WARNING, "isArrayGuardAlwaysTrue", new Object[] { pos, type, DynamicLinker.getLinkedCallSiteLocation() });
        return constantTrue(type);
    }
    if(!declaredType.isAssignableFrom(Object[].class)) {
        LOG.log(Level.WARNING, "isArrayGuardAlwaysFalse", new Object[] { pos, type, DynamicLinker.getLinkedCallSiteLocation() });
        return constantFalse(type);
    }
    return asType(IS_ARRAY, pos, type);
}
 

@Test
public void test254() throws Throwable {
    final int ARITY = 254;
    System.out.println("test"+ARITY);
    Object[] a = testArgs(ARITY);
    Object r0 = hashArguments(a);
    Object r;
    r = hashArguments_254(
// <editor-fold defaultstate="collapsed" desc="a[0x00], a[0x01], a[0x02], a[0x03], a[0x04], ...">
a[0x00], a[0x01], a[0x02], a[0x03], a[0x04], a[0x05], a[0x06], a[0x07], a[0x08], a[0x09], a[0x0A], a[0x0B], a[0x0C], a[0x0D], a[0x0E], a[0x0F],
a[0x10], a[0x11], a[0x12], a[0x13], a[0x14], a[0x15], a[0x16], a[0x17], a[0x18], a[0x19], a[0x1A], a[0x1B], a[0x1C], a[0x1D], a[0x1E], a[0x1F],
a[0x20], a[0x21], a[0x22], a[0x23], a[0x24], a[0x25], a[0x26], a[0x27], a[0x28], a[0x29], a[0x2A], a[0x2B], a[0x2C], a[0x2D], a[0x2E], a[0x2F],
a[0x30], a[0x31], a[0x32], a[0x33], a[0x34], a[0x35], a[0x36], a[0x37], a[0x38], a[0x39], a[0x3A], a[0x3B], a[0x3C], a[0x3D], a[0x3E], a[0x3F],
a[0x40], a[0x41], a[0x42], a[0x43], a[0x44], a[0x45], a[0x46], a[0x47], a[0x48], a[0x49], a[0x4A], a[0x4B], a[0x4C], a[0x4D], a[0x4E], a[0x4F],
a[0x50], a[0x51], a[0x52], a[0x53], a[0x54], a[0x55], a[0x56], a[0x57], a[0x58], a[0x59], a[0x5A], a[0x5B], a[0x5C], a[0x5D], a[0x5E], a[0x5F],
a[0x60], a[0x61], a[0x62], a[0x63], a[0x64], a[0x65], a[0x66], a[0x67], a[0x68], a[0x69], a[0x6A], a[0x6B], a[0x6C], a[0x6D], a[0x6E], a[0x6F],
a[0x70], a[0x71], a[0x72], a[0x73], a[0x74], a[0x75], a[0x76], a[0x77], a[0x78], a[0x79], a[0x7A], a[0x7B], a[0x7C], a[0x7D], a[0x7E], a[0x7F],
a[0x80], a[0x81], a[0x82], a[0x83], a[0x84], a[0x85], a[0x86], a[0x87], a[0x88], a[0x89], a[0x8A], a[0x8B], a[0x8C], a[0x8D], a[0x8E], a[0x8F],
a[0x90], a[0x91], a[0x92], a[0x93], a[0x94], a[0x95], a[0x96], a[0x97], a[0x98], a[0x99], a[0x9A], a[0x9B], a[0x9C], a[0x9D], a[0x9E], a[0x9F],
a[0xA0], a[0xA1], a[0xA2], a[0xA3], a[0xA4], a[0xA5], a[0xA6], a[0xA7], a[0xA8], a[0xA9], a[0xAA], a[0xAB], a[0xAC], a[0xAD], a[0xAE], a[0xAF],
a[0xB0], a[0xB1], a[0xB2], a[0xB3], a[0xB4], a[0xB5], a[0xB6], a[0xB7], a[0xB8], a[0xB9], a[0xBA], a[0xBB], a[0xBC], a[0xBD], a[0xBE], a[0xBF],
a[0xC0], a[0xC1], a[0xC2], a[0xC3], a[0xC4], a[0xC5], a[0xC6], a[0xC7], a[0xC8], a[0xC9], a[0xCA], a[0xCB], a[0xCC], a[0xCD], a[0xCE], a[0xCF],
a[0xD0], a[0xD1], a[0xD2], a[0xD3], a[0xD4], a[0xD5], a[0xD6], a[0xD7], a[0xD8], a[0xD9], a[0xDA], a[0xDB], a[0xDC], a[0xDD], a[0xDE], a[0xDF],
a[0xE0], a[0xE1], a[0xE2], a[0xE3], a[0xE4], a[0xE5], a[0xE6], a[0xE7], a[0xE8], a[0xE9], a[0xEA], a[0xEB], a[0xEC], a[0xED], a[0xEE], a[0xEF],
a[0xF0], a[0xF1], a[0xF2], a[0xF3], a[0xF4], a[0xF5], a[0xF6], a[0xF7],
// </editor-fold>
a[0xF8], a[0xF9], a[0xFA], a[0xFB], a[0xFC], a[0xFD]); // hashArguments_254
    assertEquals(r0, r);
    MethodType mt = MethodType.genericMethodType(ARITY);
    MethodHandle mh = MethodHandles.lookup().findStatic(BigArityTest.class, "hashArguments_"+ARITY, mt);
    test254(mh, a, r0);
    MethodHandle mh_CA = MH_hashArguments_VA.asFixedArity().asCollector(Object[].class, ARITY);
    test254(mh_CA, a, r0);
}
 

/**
 * Creates a guard method handle with arguments of a specified type, but with boolean return value. When invoked, it
 * returns true if the first argument is of the specified class (exactly of it, not a subclass). The rest of the
 * arguments will be ignored.
 *
 * @param clazz the class of the first argument to test for
 * @param type the method type
 * @return a method handle testing whether its first argument is of the specified class.
 */
@SuppressWarnings("boxing")
public static MethodHandle isOfClass(final Class<?> clazz, final MethodType type) {
    final Class<?> declaredType = type.parameterType(0);
    if(clazz == declaredType) {
        LOG.log(Level.WARNING, "isOfClassGuardAlwaysTrue", new Object[] { clazz.getName(), 0, type, DynamicLinker.getLinkedCallSiteLocation() });
        return constantTrue(type);
    }
    if(!declaredType.isAssignableFrom(clazz)) {
        LOG.log(Level.WARNING, "isOfClassGuardAlwaysFalse", new Object[] { clazz.getName(), 0, type, DynamicLinker.getLinkedCallSiteLocation() });
        return constantFalse(type);
    }
    return getClassBoundArgumentTest(IS_OF_CLASS, clazz, 0, type);
}
 

/**
 * Test of hashCode method, of class MethodType.
 */
@Test
public void testHashCode() {
    System.out.println("hashCode");
    MethodType instance = mt_viS;
    ArrayList<Class<?>> types = new ArrayList<>();
    types.add(instance.returnType());
    types.addAll(instance.parameterList());
    int expResult = types.hashCode();
    int result = instance.hashCode();
    assertEquals(expResult, result);
}
 

public static CallSite runtimeBootstrap(MethodHandles.Lookup caller, String name, MethodType type) {
    assert "rt:stack".equals(name) || "rt:locals".equals(name);
    MethodHandle mh = MethodHandles.identity(Object[].class);
    mh = mh.asCollector(Object[].class, type.parameterCount());
    mh = mh.asType(type);
    return new ConstantCallSite(mh);
}
 

@Test
public void testHasWrappers() {
    System.out.println("hasWrappers");
    MethodType[] instances = {mt_viS, mt_OO2, mt_vv, mt_Ov, mt_iSI, mt_ISi, mt_ISI, mt_iSi};
    boolean[] expResults =   {false,  false,  false, false, true,   true,   true,   false};
    for (int i = 0; i < instances.length; i++) {
        System.out.println("  hasWrappers "+instances[i]);
        boolean result = instances[i].hasWrappers();
        assertEquals("#"+i, expResults[i], result);
    }
}
 

@Test
public void testWrap() {
    System.out.println("wrap");
    MethodType[] instances =  {mt_viS, mt_OO2, mt_vv, mt_Ov, mt_iSI, mt_ISi, mt_ISI, mt_iSi};
    MethodType[] expResults = {mt_VIS, mt_OO2, mt_Vv, mt_Ov, mt_ISI, mt_ISI, mt_ISI, mt_ISI};
    for (int i = 0; i < instances.length; i++) {
        MethodType result = instances[i].wrap();
        assertSame("#"+i, expResults[i], result);
    }
}
 

static void testConvert(Wrapper src, Wrapper dst, long tval) throws Throwable {
    if (dst == Wrapper.OBJECT || src == Wrapper.OBJECT)  return;  // must have prims
    if (dst == Wrapper.VOID   || src == Wrapper.VOID  )  return;  // must have values
    boolean testSingleCase = (tval != 0);
    final long tvalInit = tval;
    MethodHandle conv = ValueConversions.convertPrimitive(src, dst);
    MethodType convType = MethodType.methodType(dst.primitiveType(), src.primitiveType());
    assertEquals(convType, conv.type());
    MethodHandle converter = conv.asType(conv.type().changeReturnType(Object.class));
    for (;;) {
        long n = tval;
        Object testValue = src.wrap(n);
        Object expResult = dst.cast(testValue, dst.primitiveType());
        Object result;
        switch (src) {
            case INT:     result = converter.invokeExact((int)n); break;
            case LONG:    result = converter.invokeExact(/*long*/n); break;
            case FLOAT:   result = converter.invokeExact((float)n); break;
            case DOUBLE:  result = converter.invokeExact((double)n); break;
            case CHAR:    result = converter.invokeExact((char)n); break;
            case BYTE:    result = converter.invokeExact((byte)n); break;
            case SHORT:   result = converter.invokeExact((short)n); break;
            case BOOLEAN: result = converter.invokeExact((n & 1) != 0); break;
            default:  throw new AssertionError();
        }
        assertEquals("(src,dst,n,testValue)="+Arrays.asList(src,dst,"0x"+Long.toHexString(n),testValue),
                     expResult, result);
        if (testSingleCase)  break;
        // next test value:
        tval = nextTestValue(tval);
        if (tval == tvalInit)  break;  // repeat
    }
}
 

@Override
MethodType getGenericType() {
    // 2 is for (callee, this)
    if (isVariableArity()) {
        return MethodType.genericMethodType(2, true);
    }
    return MethodType.genericMethodType(2 + getArity());
}
 

/** Make sure the method types are all distinct. */
@Test
public void testDistinct() {
    List<MethodType> gallery2 = new ArrayList<>();
    for (MethodType mt : GALLERY) {
        assertFalse(mt.toString(), gallery2.contains(mt));
        gallery2.add(mt);
    }
    // check self-equality also:
    assertEquals(Arrays.asList(GALLERY), gallery2);
}
 

public static MethodHandle zeroConstantFunction(Wrapper wrap) {
    WrapperCache 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) {
        return cache.put(wrap, mh);
    }

    // use zeroInt and cast the result
    if (wrap.isSubwordOrInt() && wrap != Wrapper.INT) {
        mh = MethodHandles.explicitCastArguments(zeroConstantFunction(Wrapper.INT), type);
        return cache.put(wrap, mh);
    }
    throw new IllegalArgumentException("cannot find zero constant for " + wrap);
}