/*
* Copyright ( C ) 2016 The Android Open Source Project
*
* Licensed under the Apache License , Version 2 . 0 ( the " License " ) ;
* you may not use this file except in compliance with the License .
* You may obtain a copy of the License at
*
* http : //www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing , software
* distributed under the License is distributed on an " AS IS " BASIS ,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND , either express or implied .
* See the License for the specific language governing permissions and
* limitations under the License .
*/
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandleInfo;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodHandles.Lookup;
import java.lang.invoke.MethodType;
import java.lang.invoke.WrongMethodTypeException;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.AbstractList;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.function .Consumer;
import other.Chatty;
public class Main {
public static class A {
public A() {}
public void foo() {
System.out.println("foo_A" );
}
public static final Lookup lookup = MethodHandles.lookup();
}
public static class B extends A {
public void foo() {
System.out.println("foo_B" );
}
public static final Lookup lookup = MethodHandles.lookup();
}
public static class C extends B {
public static final Lookup lookup = MethodHandles.lookup();
}
public static class D {
private final void privateRyan() {
System.out.println("privateRyan_D" );
}
public static final Lookup lookup = MethodHandles.lookup();
}
public static class E extends D {
public static final Lookup lookup = MethodHandles.lookup();
}
private interface F {
public default void sayHi() {
System.out.println("F.sayHi()" );
}
}
public static class G implements F {
public void sayHi() {
System.out.println("G.sayHi()" );
}
public MethodHandles.Lookup getLookup() {
return MethodHandles.lookup();
}
}
public static class H implements Chatty {
public void chatter() {
System.out.println("H.chatter()" );
}
public MethodHandles.Lookup getLookup() {
return MethodHandles.lookup();
}
}
public static class I {
public static void someVoidMethod() {
}
}
public static void main(String[] args) throws Throwable {
testfindSpecial_invokeSuperBehaviour();
testfindSpecial_invokeDirectBehaviour();
testExceptionDetailMessages();
testfindVirtual();
testfindStatic();
testUnreflects();
testAsType();
testConstructors();
testStringConstructors();
testReturnValues();
testReturnValueConversions();
testVariableArity();
testVariableArity_MethodHandles_bind();
testRevealDirect();
testReflectiveCalls();
testInterfaceSpecial();
}
public static void testfindSpecial_invokeSuperBehaviour() throws Throwable {
// This is equivalent to an invoke-super instruction where the referrer
// is B.class.
MethodHandle mh1 = B.lookup.findSpecial(A.class /* refC */, "foo",
MethodType.methodType(void .class ), B.class /* specialCaller */);
A aInstance = new A();
B bInstance = new B();
C cInstance = new C();
// This should be as if an invoke-super was called from one of B's methods.
mh1.invokeExact(bInstance);
mh1.invoke(bInstance);
// This should not work. The receiver type in the handle will be suitably
// restricted to B and subclasses.
try {
mh1.invoke(aInstance);
System.out.println("mh1.invoke(aInstance) should not succeeed" );
} catch (ClassCastException expected) {
}
try {
mh1.invokeExact(aInstance);
System.out.println("mh1.invoke(aInstance) should not succeeed" );
} catch (WrongMethodTypeException expected) {
}
// This should *still* be as if an invoke-super was called from one of C's
// methods, despite the fact that we're operating on a C.
mh1.invoke(cInstance);
// Now that C is the special caller, the next invoke will call B.foo.
MethodHandle mh2 = C.lookup.findSpecial(A.class /* refC */, "foo",
MethodType.methodType(void .class ), C.class /* specialCaller */);
mh2.invokeExact(cInstance);
// Shouldn't allow invoke-super semantics from an unrelated special caller.
try {
C.lookup.findSpecial(A.class , "foo" ,
MethodType.methodType(void .class ), D.class /* specialCaller */);
System.out.println("findSpecial(A.class, foo, .. D.class) unexpectedly succeeded." );
} catch (IllegalAccessException expected) {
}
// Check return type matches for find.
try {
B.lookup.findSpecial(A.class /* refC */, "foo",
MethodType.methodType(int .class ), B.class /* specialCaller */);
fail();
} catch (NoSuchMethodException e) {}
// Check constructors
try {
B.lookup.findSpecial(A.class /* refC */, "<init>",
MethodType.methodType(void .class ), B.class /* specialCaller */);
fail();
} catch (NoSuchMethodException e) {}
}
public static void testfindSpecial_invokeDirectBehaviour() throws Throwable {
D dInstance = new D();
MethodHandle mh3 = D.lookup.findSpecial(D.class , "privateRyan" ,
MethodType.methodType(void .class ), D.class /* specialCaller */);
mh3.invoke(dInstance);
try {
mh3.invokeExact((D) null );
fail("Expected NPE to be thrown" );
} catch (NullPointerException expected) {
}
// The private method shouldn't be accessible from any special caller except
// itself...
try {
D.lookup.findSpecial(D.class , "privateRyan" , MethodType.methodType(void .class ), C.class );
System.out.println("findSpecial(privateRyan, C.class) unexpectedly succeeded" );
} catch (IllegalAccessException expected) {
}
// ... or from any lookup context except its own.
try {
E.lookup.findSpecial(D.class , "privateRyan" , MethodType.methodType(void .class ), E.class );
System.out.println("findSpecial(privateRyan, E.class) unexpectedly succeeded" );
} catch (IllegalAccessException expected) {
}
}
public static void testExceptionDetailMessages() throws Throwable {
MethodHandle handle = MethodHandles.lookup().findVirtual(String.class , "concat" ,
MethodType.methodType(String.class , String.class ));
try {
handle.invokeExact("a" , new Object());
System.out.println("invokeExact(\" a\", new Object()) unexpectedly succeeded." );
} catch (WrongMethodTypeException ex) {
System.out.println("Received WrongMethodTypeException exception" );
}
}
public interface Foo {
public String foo();
}
public interface Bar extends Foo {
public String bar();
}
public static abstract class BarAbstractSuper {
public abstract String abstractSuperPublicMethod();
}
public static class BarSuper extends BarAbstractSuper {
public String superPublicMethod() {
return "superPublicMethod" ;
}
protected String superProtectedMethod() {
return "superProtectedMethod" ;
}
public String abstractSuperPublicMethod() {
return "abstractSuperPublicMethod" ;
}
String superPackageMethod() {
return "superPackageMethod" ;
}
}
public static class BarImpl extends BarSuper implements Bar {
public BarImpl() {
}
@Override
public String foo() {
return "foo" ;
}
@Override
public String bar() {
return "bar" ;
}
public String add(int x, int y) {
return Arrays.toString(new int [] { x, y });
}
private String privateMethod() { return "privateMethod" ; }
public static String staticMethod() { return staticString; }
private static String staticString;
{
// Static constructor
staticString = Long .toString(System.currentTimeMillis());
}
static final MethodHandles.Lookup lookup = MethodHandles.lookup();
}
public static void testfindVirtual() throws Throwable {
// Virtual lookups on static methods should not succeed.
try {
MethodHandles.lookup().findVirtual(
BarImpl.class , "staticMethod" , MethodType.methodType(String.class ));
System.out.println("findVirtual(staticMethod) unexpectedly succeeded" );
} catch (IllegalAccessException expected) {
}
// Virtual lookups on private methods should not succeed, unless the Lookup
// context had sufficient privileges.
try {
MethodHandles.lookup().findVirtual(
BarImpl.class , "privateMethod" , MethodType.methodType(String.class ));
System.out.println("findVirtual(privateMethod) unexpectedly succeeded" );
} catch (IllegalAccessException expected) {
}
// Virtual lookup on a private method with a context that *does* have sufficient
// privileges.
MethodHandle mh = BarImpl.lookup.findVirtual(
BarImpl.class , "privateMethod" , MethodType.methodType(String.class ));
String str = (String) mh.invoke(new BarImpl());
if (!"privateMethod" .equals(str)) {
System.out.println("Unexpected return value for BarImpl#privateMethod: " + str);
}
// Find virtual must find interface methods defined by interfaces implemented
// by the class.
mh = MethodHandles.lookup().findVirtual(BarImpl.class , "foo" ,
MethodType.methodType(String.class ));
str = (String) mh.invoke(new BarImpl());
if (!"foo" .equals(str)) {
System.out.println("Unexpected return value for BarImpl#foo: " + str);
}
// Find virtual should check rtype.
try {
mh = MethodHandles.lookup().findVirtual(BarImpl.class , "foo" ,
MethodType.methodType(void .class ));
fail();
} catch (NoSuchMethodException e) {}
// And ptypes
mh = MethodHandles.lookup().findVirtual(
BarImpl.class , "add" , MethodType.methodType(String.class , int .class , int .class ));
try {
mh = MethodHandles.lookup().findVirtual(
BarImpl.class , "add" , MethodType.methodType(String.class , Integer.class , int .class ));
} catch (NoSuchMethodException e) {}
// .. and their super-interfaces.
mh = MethodHandles.lookup().findVirtual(BarImpl.class , "bar" ,
MethodType.methodType(String.class ));
str = (String) mh.invoke(new BarImpl());
if (!"bar" .equals(str)) {
System.out.println("Unexpected return value for BarImpl#bar: " + str);
}
mh = MethodHandles.lookup().findVirtual(Bar.class , "bar" ,
MethodType.methodType(String.class ));
str = (String) mh.invoke(new BarImpl());
if (!"bar" .equals(str)) {
System.out.println("Unexpected return value for BarImpl#bar: " + str);
}
mh = MethodHandles.lookup().findVirtual(BarAbstractSuper.class , "abstractSuperPublicMethod" ,
MethodType.methodType(String.class ));
str = (String) mh.invoke(new BarImpl());
if (!"abstractSuperPublicMethod" .equals(str)) {
System.out.println("Unexpected return value for BarImpl#abstractSuperPublicMethod: " + str);
}
// We should also be able to lookup public / protected / package methods in
// the super class, given sufficient access privileges.
mh = MethodHandles.lookup().findVirtual(BarImpl.class , "superPublicMethod" ,
MethodType.methodType(String.class ));
str = (String) mh.invoke(new BarImpl());
if (!"superPublicMethod" .equals(str)) {
System.out.println("Unexpected return value for BarImpl#superPublicMethod: " + str);
}
mh = MethodHandles.lookup().findVirtual(BarImpl.class , "superProtectedMethod" ,
MethodType.methodType(String.class ));
str = (String) mh.invoke(new BarImpl());
if (!"superProtectedMethod" .equals(str)) {
System.out.println("Unexpected return value for BarImpl#superProtectedMethod: " + str);
}
mh = MethodHandles.lookup().findVirtual(BarImpl.class , "superPackageMethod" ,
MethodType.methodType(String.class ));
str = (String) mh.invoke(new BarImpl());
if (!"superPackageMethod" .equals(str)) {
System.out.println("Unexpected return value for BarImpl#superPackageMethod: " + str);
}
try {
MethodHandles.lookup().findVirtual(BarImpl.class , "<init>" ,
MethodType.methodType(void .class ));
fail();
} catch (NoSuchMethodException e) {}
}
public static void testfindStatic() throws Throwable {
MethodHandles.lookup().findStatic(BarImpl.class , "staticMethod" ,
MethodType.methodType(String.class ));
try {
MethodHandles.lookup().findStatic(BarImpl.class , "staticMethod" ,
MethodType.methodType(void .class ));
fail();
} catch (NoSuchMethodException e) {}
try {
MethodHandles.lookup().findStatic(BarImpl.class , "staticMethod" ,
MethodType.methodType(String.class , int .class ));
fail();
} catch (NoSuchMethodException e) {}
try {
MethodHandles.lookup().findStatic(BarImpl.class , "<clinit>" ,
MethodType.methodType(void .class ));
fail();
} catch (NoSuchMethodException e) {}
try {
MethodHandles.lookup().findStatic(BarImpl.class , "<init>" ,
MethodType.methodType(void .class ));
fail();
} catch (NoSuchMethodException e) {}
}
static class UnreflectTester {
public String publicField;
private String privateField;
public static String publicStaticField = "publicStaticValue" ;
private static String privateStaticField = "privateStaticValue" ;
private UnreflectTester(String val) {
publicField = val;
privateField = val;
}
// NOTE: The boolean constructor argument only exists to give this a
// different signature.
public UnreflectTester(String val, boolean unused) {
this (val);
}
private static String privateStaticMethod() {
return "privateStaticMethod" ;
}
private String privateMethod() {
return "privateMethod" ;
}
public static String publicStaticMethod() {
return "publicStaticMethod" ;
}
public String publicMethod() {
return "publicMethod" ;
}
public String publicVarArgsMethod(String... args) {
return "publicVarArgsMethod" ;
}
}
public static void testUnreflects() throws Throwable {
UnreflectTester instance = new UnreflectTester("unused" );
Method publicMethod = UnreflectTester.class .getMethod("publicMethod" );
MethodHandle mh = MethodHandles.lookup().unreflect(publicMethod);
assertEquals("publicMethod" , (String) mh.invoke(instance));
assertEquals("publicMethod" , (String) mh.invokeExact(instance));
Method publicStaticMethod = UnreflectTester.class .getMethod("publicStaticMethod" );
mh = MethodHandles.lookup().unreflect(publicStaticMethod);
assertEquals("publicStaticMethod" , (String) mh.invoke());
assertEquals("publicStaticMethod" , (String) mh.invokeExact());
Method privateMethod = UnreflectTester.class .getDeclaredMethod("privateMethod" );
try {
mh = MethodHandles.lookup().unreflect(privateMethod);
fail();
} catch (IllegalAccessException expected) {}
privateMethod.setAccessible(true );
mh = MethodHandles.lookup().unreflect(privateMethod);
assertEquals("privateMethod" , (String) mh.invoke(instance));
assertEquals("privateMethod" , (String) mh.invokeExact(instance));
Method privateStaticMethod = UnreflectTester.class .getDeclaredMethod("privateStaticMethod" );
try {
mh = MethodHandles.lookup().unreflect(privateStaticMethod);
fail();
} catch (IllegalAccessException expected) {}
privateStaticMethod.setAccessible(true );
mh = MethodHandles.lookup().unreflect(privateStaticMethod);
assertEquals("privateStaticMethod" , (String) mh.invoke());
assertEquals("privateStaticMethod" , (String) mh.invokeExact());
Constructor privateConstructor = UnreflectTester.class .getDeclaredConstructor(String.class );
try {
mh = MethodHandles.lookup().unreflectConstructor(privateConstructor);
fail();
} catch (IllegalAccessException expected) {}
privateConstructor.setAccessible(true );
mh = MethodHandles.lookup().unreflectConstructor(privateConstructor);
instance = (UnreflectTester) mh.invokeExact("abc" );
assertEquals("abc" , instance.publicField);
instance = (UnreflectTester) mh.invoke("def" );
assertEquals("def" , instance.publicField);
Constructor publicConstructor = UnreflectTester.class .getConstructor(String.class ,
boolean .class );
mh = MethodHandles.lookup().unreflectConstructor(publicConstructor);
instance = (UnreflectTester) mh.invokeExact("abc" , false );
assertEquals("abc" , instance.publicField);
instance = (UnreflectTester) mh.invoke("def" , true );
assertEquals("def" , instance.publicField);
// TODO(narayan): Non exact invokes for field sets/gets are not implemented yet.
//
// assertEquals("instanceValue", (String) mh.invoke(new UnreflectTester("instanceValue")));
Field publicField = UnreflectTester.class .getField("publicField" );
mh = MethodHandles.lookup().unreflectGetter(publicField);
instance = new UnreflectTester("instanceValue" );
assertEquals("instanceValue" , (String) mh.invokeExact(instance));
mh = MethodHandles.lookup().unreflectSetter(publicField);
instance = new UnreflectTester("instanceValue" );
mh.invokeExact(instance, "updatedInstanceValue" );
assertEquals("updatedInstanceValue" , instance.publicField);
Field publicStaticField = UnreflectTester.class .getField("publicStaticField" );
mh = MethodHandles.lookup().unreflectGetter(publicStaticField);
UnreflectTester.publicStaticField = "updatedStaticValue" ;
assertEquals("updatedStaticValue" , (String) mh.invokeExact());
mh = MethodHandles.lookup().unreflectSetter(publicStaticField);
UnreflectTester.publicStaticField = "updatedStaticValue" ;
mh.invokeExact("updatedStaticValue2" );
assertEquals("updatedStaticValue2" , UnreflectTester.publicStaticField);
Field privateField = UnreflectTester.class .getDeclaredField("privateField" );
try {
mh = MethodHandles.lookup().unreflectGetter(privateField);
fail();
} catch (IllegalAccessException expected) {
}
try {
mh = MethodHandles.lookup().unreflectSetter(privateField);
fail();
} catch (IllegalAccessException expected) {
}
privateField.setAccessible(true );
mh = MethodHandles.lookup().unreflectGetter(privateField);
instance = new UnreflectTester("instanceValue" );
assertEquals("instanceValue" , (String) mh.invokeExact(instance));
mh = MethodHandles.lookup().unreflectSetter(privateField);
instance = new UnreflectTester("instanceValue" );
mh.invokeExact(instance, "updatedInstanceValue" );
assertEquals("updatedInstanceValue" , instance.privateField);
Field privateStaticField = UnreflectTester.class .getDeclaredField("privateStaticField" );
try {
mh = MethodHandles.lookup().unreflectGetter(privateStaticField);
fail();
} catch (IllegalAccessException expected) {
}
try {
mh = MethodHandles.lookup().unreflectSetter(privateStaticField);
fail();
} catch (IllegalAccessException expected) {
}
privateStaticField.setAccessible(true );
mh = MethodHandles.lookup().unreflectGetter(privateStaticField);
privateStaticField.set(null , "updatedStaticValue" );
assertEquals("updatedStaticValue" , (String) mh.invokeExact());
mh = MethodHandles.lookup().unreflectSetter(privateStaticField);
privateStaticField.set(null , "updatedStaticValue" );
mh.invokeExact("updatedStaticValue2" );
assertEquals("updatedStaticValue2" , (String) privateStaticField.get(null ));
// unreflectSpecial testing - F is an interface that G implements
G g = new G();
g.sayHi(); // prints "G.sayHi()"
MethodHandles.Lookup lookupInG = g.getLookup();
Method methodInG = G.class .getDeclaredMethod("sayHi" );
lookupInG.unreflectSpecial(methodInG, G.class ).invoke(g); // prints "G.sayHi()"
Method methodInF = F.class .getDeclaredMethod("sayHi" );
lookupInG.unreflect(methodInF).invoke(g); // prints "G.sayHi()"
lookupInG.in(G.class ).unreflectSpecial(methodInF, G.class ).invoke(g); // prints "F.sayHi()"
lookupInG.unreflectSpecial(methodInF, G.class ).bindTo(g).invokeWithArguments();
// unreflectSpecial testing - other.Chatty is an interface that H implements
H h = new H();
h.chatter();
MethodHandles.Lookup lookupInH = h.getLookup();
Method methodInH = H.class .getDeclaredMethod("chatter" );
lookupInH.unreflectSpecial(methodInH, H.class ).invoke(h);
Method methodInChatty = Chatty.class .getDeclaredMethod("chatter" );
lookupInH.unreflect(methodInChatty).invoke(h);
lookupInH.in(H.class ).unreflectSpecial(methodInChatty, H.class ).invoke(h);
lookupInH.unreflectSpecial(methodInChatty, H.class ).bindTo(h).invokeWithArguments();
}
// This method only exists to fool Jack's handling of types. See b/32536744.
public static CharSequence getSequence() {
return "foo" ;
}
public static void testAsType() throws Throwable {
// The type of this handle is (String, String)String.
MethodHandle mh = MethodHandles.lookup().findVirtual(String.class ,
"concat" , MethodType.methodType(String.class , String.class ));
// Change it to (CharSequence, String)Object.
MethodHandle asType = mh.asType(
MethodType.methodType(Object.class , CharSequence.class , String.class ));
Object obj = asType.invokeExact((CharSequence) getSequence(), "bar" );
assertEquals("foobar" , (String) obj);
// Should fail due to a wrong return type.
try {
String str = (String) asType.invokeExact((CharSequence) getSequence(), "bar" );
fail();
} catch (WrongMethodTypeException expected) {
}
// Should fail due to a wrong argument type (String instead of Charsequence).
try {
String str = (String) asType.invokeExact("baz" , "bar" );
fail();
} catch (WrongMethodTypeException expected) {
}
// Calls to asType should fail if the types are not convertible.
//
// Bad return type conversion.
try {
mh.asType(MethodType.methodType(int .class , String.class , String.class ));
fail();
} catch (WrongMethodTypeException expected) {
}
// Bad argument conversion.
try {
mh.asType(MethodType.methodType(String.class , int .class , String.class ));
fail();
} catch (WrongMethodTypeException expected) {
}
// Zero / null introduction
MethodHandle voidMH = MethodHandles.lookup().findStatic(I.class , "someVoidMethod" ,
MethodType.methodType(void .class ));
{
MethodHandle booleanMH = voidMH.asType(MethodType.methodType(boolean .class ));
assertEquals(boolean .class , booleanMH.type().returnType());
assertEquals(false , booleanMH.invoke());
}
{
MethodHandle intMH = voidMH.asType(MethodType.methodType(int .class ));
assertEquals(int .class , intMH.type().returnType());
assertEquals(0 , intMH.invoke());
}
{
MethodHandle longMH = voidMH.asType(MethodType.methodType(long .class ));
assertEquals(long .class , longMH.type().returnType());
assertEquals(0 L, longMH.invoke());
}
{
MethodHandle objMH = voidMH.asType(MethodType.methodType(Object.class ));
assertEquals(Object.class , objMH.type().returnType());
assertEquals(null , objMH.invoke());
}
// Applying asType() twice.
{
MethodHandle valueOfMH = MethodHandles.lookup().findStatic(Integer.class , "valueOf" ,
MethodType.methodType(Integer.class , int .class ));
MethodHandle atMH = valueOfMH.asType(MethodType.methodType(int .class , Object.class ));
MethodHandle at2MH = atMH.asType(MethodType.methodType(Integer.class , int .class ));
assertEquals(valueOfMH.type(), at2MH.type());
assertEquals(Integer.valueOf(2 ), (Integer) valueOfMH.invokeExact(2 ));
assertEquals(12345678 , (int ) atMH.invokeExact((Object) Integer.valueOf(12345678 )));
assertEquals(Integer.valueOf(987654321 ), (Integer) at2MH.invokeExact(987654321 ));
}
{
MethodHandle valueOfMH = MethodHandles.lookup().findStatic(Double .class , "valueOf" ,
MethodType.methodType(Double .class , double .class ));
MethodHandle atMH = valueOfMH.asType(MethodType.methodType(double .class , Object.class ));
MethodHandle at2MH = atMH.asType(MethodType.methodType(Double .class , double .class ));
assertEquals(valueOfMH.type(), at2MH.type());
assertEquals(Double .valueOf(1 .125 e3), (Double ) valueOfMH.invokeExact(1 .125 e3));
assertEquals(2 .5 e-3 , (double ) atMH.invokeExact((Object) Double .valueOf(2 .5 e-3 )));
assertEquals(Double .valueOf(3 .125 e-2 ), (Double ) at2MH.invokeExact(3 .125 e-2 ));
}
}
public static void assertTrue(boolean value) {
if (!value) {
throw new AssertionError("assertTrue value: " + value);
}
}
public static void assertFalse(boolean value) {
if (value) {
throw new AssertionError("assertTrue value: " + value);
}
}
public static void assertEquals(int i1, int i2) {
if (i1 == i2) { return ; }
throw new AssertionError("assertEquals i1: " + i1 + ", i2: " + i2);
}
public static void assertEquals(long i1, long i2) {
if (i1 == i2) { return ; }
throw new AssertionError("assertEquals l1: " + i1 + ", l2: " + i2);
}
public static void assertEquals(Object o, Object p) {
if (o == p) { return ; }
if (o != null && p != null && o.equals(p)) { return ; }
throw new AssertionError("assertEquals: o1: " + o + ", o2: " + p);
}
public static void assertEquals(String s1, String s2) {
if (s1 == s2) {
return ;
}
if (s1 != null && s2 != null && s1.equals(s2)) {
return ;
}
throw new AssertionError("assertEquals s1: " + s1 + ", s2: " + s2);
}
public static void fail() {
System.out.println("fail" );
Thread .dumpStack();
}
public static void fail(String message) {
System.out.println("fail: " + message);
Thread .dumpStack();
}
public static void testConstructors() throws Throwable {
MethodHandle mh =
MethodHandles.lookup().findConstructor(Float .class ,
MethodType.methodType(void .class ,
float .class ));
Float value = (Float ) mh.invokeExact(0 .33 f);
if (value.floatValue() != 0 .33 f) {
fail("Unexpected float value from invokeExact " + value.floatValue());
}
value = (Float ) mh.invoke(3 .34 f);
if (value.floatValue() != 3 .34 f) {
fail("Unexpected float value from invoke " + value.floatValue());
}
mh = MethodHandles.lookup().findConstructor(Double .class ,
MethodType.methodType(void .class , String.class ));
Double d = (Double ) mh.invoke("8.45e3" );
if (d.doubleValue() != 8 .45 e3) {
fail("Unexpected double value from Double(String) " + value.doubleValue());
}
mh = MethodHandles.lookup().findConstructor(Double .class ,
MethodType.methodType(void .class , double .class ));
d = (Double ) mh.invoke(8 .45 e3);
if (d.doubleValue() != 8 .45 e3) {
fail("Unexpected double value from Double(double) " + value.doubleValue());
}
// Primitive type
try {
mh = MethodHandles.lookup().findConstructor(int .class , MethodType.methodType(void .class ));
fail("Unexpected lookup success for primitive constructor" );
} catch (NoSuchMethodException e) {}
// Interface
try {
mh = MethodHandles.lookup().findConstructor(Readable.class ,
MethodType.methodType(void .class ));
fail("Unexpected lookup success for interface constructor" );
} catch (NoSuchMethodException e) {}
// Abstract
mh = MethodHandles.lookup().findConstructor(Process.class , MethodType.methodType(void .class ));
try {
mh.invoke();
fail("Unexpected ability to instantiate an abstract class" );
} catch (InstantiationException e) {}
// Non-existent
try {
MethodHandle bad = MethodHandles.lookup().findConstructor(
String.class , MethodType.methodType(String.class , Float .class ));
fail("Unexpected success for non-existent constructor" );
} catch (NoSuchMethodException e) {}
// Non-void constructor search. (I)I instead of (I)V.
try {
MethodHandle foo = MethodHandles.lookup().findConstructor(
Integer.class , MethodType.methodType(Integer.class , Integer.class ));
fail("Unexpected success for non-void type for findConstructor" );
} catch (NoSuchMethodException e) {}
// Array class constructor.
try {
MethodHandle foo = MethodHandles.lookup().findConstructor(
Object[].class , MethodType.methodType(void .class ));
fail("Unexpected success for array class type for findConstructor" );
} catch (NoSuchMethodException e) {}
// Child class constructor (b/143343351)
{
MethodHandle handle = MethodHandles.lookup().findConstructor(
ArrayList.class , MethodType.methodType(void .class ));
AbstractList list = (AbstractList) handle.asType(MethodType.methodType(AbstractList.class ))
.invokeExact();
}
}
public static void testStringConstructors() throws Throwable {
final String testPattern = "The system as we know it is broken" ;
// String()
MethodHandle mh = MethodHandles.lookup().findConstructor(
String.class , MethodType.methodType(void .class ));
String s = (String) mh.invokeExact();
if (!s.equals("" )) {
fail("Unexpected empty string constructor result: '" + s + "'" );
}
// String(String)
mh = MethodHandles.lookup().findConstructor(
String.class , MethodType.methodType(void .class , String.class ));
s = (String) mh.invokeExact(testPattern);
if (!s.equals(testPattern)) {
fail("Unexpected string constructor result: '" + s + "'" );
}
// String(char[])
mh = MethodHandles.lookup().findConstructor(
String.class , MethodType.methodType(void .class , char [].class ));
s = (String) mh.invokeExact(testPattern.toCharArray());
if (!s.equals(testPattern)) {
fail("Unexpected string constructor result: '" + s + "'" );
}
// String(char[], int, int)
mh = MethodHandles.lookup().findConstructor(
String.class , MethodType.methodType(void .class , char [].class , int .class , int .class ));
s = (String) mh.invokeExact(new char [] { 'a' , 'b' , 'c' , 'd' , 'e' }, 2 , 3 );
if (!s.equals("cde" )) {
fail("Unexpected string constructor result: '" + s + "'" );
}
// String(int[] codePoints, int offset, int count)
StringBuffer sb = new StringBuffer(testPattern);
int [] codePoints = new int [sb.codePointCount(0 , sb.length())];
for (int i = 0 ; i < sb.length(); ++i) {
codePoints[i] = sb.codePointAt(i);
}
mh = MethodHandles.lookup().findConstructor(
String.class , MethodType.methodType(void .class , int [].class , int .class , int .class ));
s = (String) mh.invokeExact(codePoints, 0 , codePoints.length);
if (!s.equals(testPattern)) {
fail("Unexpected string constructor result: '" + s + "'" );
}
// String(byte ascii[], int hibyte, int offset, int count)
byte [] ascii = testPattern.getBytes(StandardCharsets.US_ASCII);
mh = MethodHandles.lookup().findConstructor(
String.class , MethodType.methodType(void .class , byte [].class , int .class , int .class ));
s = (String) mh.invokeExact(ascii, 0 , ascii.length);
if (!s.equals(testPattern)) {
fail("Unexpected string constructor result: '" + s + "'" );
}
// String(byte bytes[], int offset, int length, String charsetName)
mh = MethodHandles.lookup().findConstructor(
String.class ,
MethodType.methodType(void .class , byte [].class , int .class , int .class , String.class ));
s = (String) mh.invokeExact(ascii, 0 , 5 , StandardCharsets.US_ASCII.name());
if (!s.equals(testPattern.substring(0 , 5 ))) {
fail("Unexpected string constructor result: '" + s + "'" );
}
// String(byte bytes[], int offset, int length, Charset charset)
mh = MethodHandles.lookup().findConstructor(
String.class ,
MethodType.methodType(void .class , byte [].class , int .class , int .class , Charset.class ));
s = (String) mh.invokeExact(ascii, 0 , 5 , StandardCharsets.US_ASCII);
if (!s.equals(testPattern.substring(0 , 5 ))) {
fail("Unexpected string constructor result: '" + s + "'" );
}
// String(byte bytes[], String charsetName)
mh = MethodHandles.lookup().findConstructor(
String.class ,
MethodType.methodType(void .class , byte [].class , String.class ));
s = (String) mh.invokeExact(ascii, StandardCharsets.US_ASCII.name());
if (!s.equals(testPattern)) {
fail("Unexpected string constructor result: '" + s + "'" );
}
// String(byte bytes[], Charset charset)
mh = MethodHandles.lookup().findConstructor(
String.class , MethodType.methodType(void .class , byte [].class , Charset.class ));
s = (String) mh.invokeExact(ascii, StandardCharsets.US_ASCII);
if (!s.equals(testPattern)) {
fail("Unexpected string constructor result: '" + s + "'" );
}
// String(byte bytes[], int offset, int length)
mh = MethodHandles.lookup().findConstructor(
String.class , MethodType.methodType(void .class , byte [].class , int .class , int .class ));
s = (String) mh.invokeExact(ascii, 1 , ascii.length - 2 );
s = testPattern.charAt(0 ) + s + testPattern.charAt(testPattern.length() - 1 );
if (!s.equals(testPattern)) {
fail("Unexpected string constructor result: '" + s + "'" );
}
// String(byte bytes[])
mh = MethodHandles.lookup().findConstructor(
String.class , MethodType.methodType(void .class , byte [].class ));
s = (String) mh.invokeExact(ascii);
if (!s.equals(testPattern)) {
fail("Unexpected string constructor result: '" + s + "'" );
}
// String(StringBuffer buffer)
mh = MethodHandles.lookup().findConstructor(
String.class , MethodType.methodType(void .class , StringBuffer.class ));
s = (String) mh.invokeExact(sb);
if (!s.equals(testPattern)) {
fail("Unexpected string constructor result: '" + s + "'" );
}
// Child class constructor (b/143343351)
{
MethodHandle handle = MethodHandles.lookup().findConstructor(
String.class , MethodType.methodType(void .class ));
CharSequence o = (CharSequence) handle.asType(MethodType.methodType(CharSequence.class ))
.invokeExact();
if (!o.equals("" )) {
fail("Unexpected child class constructor result: '" + o + "'" );
}
}
System.out.println("String constructors done." );
}
private static void testReturnValues() throws Throwable {
Lookup lookup = MethodHandles.lookup();
// byte
MethodHandle mhByteValue =
lookup.findVirtual(Byte .class , "byteValue" , MethodType.methodType(byte .class ));
assertEquals((byte ) -77 , (byte ) mhByteValue.invokeExact(Byte .valueOf((byte ) -77 )));
assertEquals((byte ) -77 , (byte ) mhByteValue.invoke(Byte .valueOf((byte ) -77 )));
// char
MethodHandle mhCharacterValue =
lookup.findStaticGetter(Character.class , "MAX_SURROGATE" , char .class );
assertEquals(Character.MAX_SURROGATE, (char ) mhCharacterValue.invokeExact());
assertEquals(Character.MAX_SURROGATE, (char ) mhCharacterValue.invoke());
// double
MethodHandle mhSin =
lookup.findStatic(
Math.class , "sin" , MethodType.methodType(double .class , double .class ));
for (double i = -Math.PI; i <= Math.PI; i += Math.PI / 8 ) {
assertEquals(Math.sin(i), (double ) mhSin.invokeExact(i));
assertEquals(Math.sin(i), (double ) mhSin.invoke(i));
}
// float
MethodHandle mhAbsFloat =
lookup.findStatic(
Math.class , "abs" , MethodType.methodType(float .class , float .class ));
assertEquals(Math.abs(-3 .3 e6f), (float ) mhAbsFloat.invokeExact(-3 .3 e6f));
assertEquals(Math.abs(-3 .3 e6f), (float ) mhAbsFloat.invoke(-3 .3 e6f));
// int
MethodHandle mhAbsInt =
lookup.findStatic(Math.class , "abs" , MethodType.methodType(int .class , int .class ));
assertEquals(Math.abs(-1000 ), (int ) mhAbsInt.invokeExact(-1000 ));
assertEquals(Math.abs(-1000 ), (int ) mhAbsInt.invoke(-1000 ));
// long
MethodHandle mhMaxLong =
lookup.findStatic(
Math.class ,
"max" ,
MethodType.methodType(long .class , long .class , long .class ));
assertEquals(
Long .MAX_VALUE, (long ) mhMaxLong.invokeExact(Long .MAX_VALUE, Long .MAX_VALUE / 2 ));
assertEquals(Long .MAX_VALUE, (long ) mhMaxLong.invoke(Long .MAX_VALUE, Long .MAX_VALUE / 2 ));
assertEquals(0 x0123456789abcdefL, (long ) mhMaxLong.invokeExact(0 x0123456789abcdefL, 0 L));
assertEquals(0 x0123456789abcdefL, (long ) mhMaxLong.invoke(0 x0123456789abcdefL, 0 L));
// ref
MethodHandle mhShortValueOf =
lookup.findStatic(
Short .class , "valueOf" , MethodType.methodType(Short .class , short .class ));
assertEquals(
(short ) -7890 , ((Short ) mhShortValueOf.invokeExact((short ) -7890 )).shortValue());
assertEquals((short ) -7890 , ((Short ) mhShortValueOf.invoke((short ) -7890 )).shortValue());
// array
int [] array = {Integer.MIN_VALUE, -1 , 0 , +1 , Integer.MAX_VALUE};
MethodHandle mhCopyOf =
lookup.findStatic(
Arrays.class , "copyOf" , MethodType.methodType(int [].class , int [].class , int .class ));
assertTrue(Arrays.equals(array, (int []) mhCopyOf.invokeExact(array, array.length)));
assertTrue(Arrays.equals(array, (int []) mhCopyOf.invoke(array, array.length)));
// short
MethodHandle mhShortValue =
lookup.findVirtual(Short .class , "shortValue" , MethodType.methodType(short .class ));
assertEquals((short ) 12131 , (short ) mhShortValue.invokeExact(Short .valueOf((short ) 12131 )));
assertEquals((short ) 12131 , (short ) mhShortValue.invoke(Short .valueOf((short ) 12131 )));
// boolean
MethodHandle mhBooleanValue =
lookup.findVirtual(
Boolean .class , "booleanValue" , MethodType.methodType(boolean .class ));
assertEquals(true , (boolean ) mhBooleanValue.invokeExact(Boolean .valueOf(true )));
assertEquals(true , (boolean ) mhBooleanValue.invoke(Boolean .valueOf(true )));
assertEquals(false , (boolean ) mhBooleanValue.invokeExact(Boolean .valueOf(false )));
assertEquals(false , (boolean ) mhBooleanValue.invoke(Boolean .valueOf(false )));
System.out.println("testReturnValues done." );
}
private static void testReferenceReturnValueConversions() throws Throwable {
MethodHandle mh = MethodHandles.lookup().findStatic(
Float .class , "valueOf" , MethodType.methodType(Float .class , String.class ));
// No conversion
Float f = (Float ) mh.invokeExact("1.375" );
if (f.floatValue() != 1 .375 ) {
fail();
}
f = (Float ) mh.invoke("1.875" );
if (f.floatValue() != 1 .875 ) {
fail();
}
// Bad conversion
try {
int i = (int ) mh.invokeExact("7.77" );
fail();
} catch (WrongMethodTypeException e) {}
try {
int i = (int ) mh.invoke("7.77" );
fail();
} catch (WrongMethodTypeException e) {}
// Assignment to super-class.
Number n = (Number) mh.invoke("1.11" );
try {
Number o = (Number) mh.invokeExact("1.11" );
fail();
} catch (WrongMethodTypeException e) {}
// Assignment to widened boxed primitive class.
try {
Double u = (Double ) mh.invoke("1.11" );
fail();
} catch (ClassCastException e) {}
try {
Double v = (Double ) mh.invokeExact("1.11" );
fail();
} catch (WrongMethodTypeException e) {}
// Unboxed
float p = (float ) mh.invoke("1.11" );
if (p != 1 .11 f) {
fail();
}
// Unboxed and widened
double d = (double ) mh.invoke("2.5" );
if (d != 2 .5 ) {
fail();
}
// Interface
Comparable<Float > c = (Comparable<Float >) mh.invoke("2.125" );
if (c.compareTo(new Float (2 .125 f)) != 0 ) {
fail();
}
System.out.println("testReferenceReturnValueConversions done." );
}
private static void testPrimitiveReturnValueConversions() throws Throwable {
MethodHandle mh = MethodHandles.lookup().findStatic(
Math.class , "min" , MethodType.methodType(int .class , int .class , int .class ));
final int SMALL = -8972 ;
final int LARGE = 7932529 ;
// No conversion
if ((int ) mh.invokeExact(LARGE, SMALL) != SMALL) {
fail();
} else if ((int ) mh.invoke(LARGE, SMALL) != SMALL) {
fail();
} else if ((int ) mh.invokeExact(SMALL, LARGE) != SMALL) {
fail();
} else if ((int ) mh.invoke(SMALL, LARGE) != SMALL) {
fail();
}
// int -> long
try {
if ((long ) mh.invokeExact(LARGE, SMALL) != (long ) SMALL) {}
fail();
} catch (WrongMethodTypeException e) {}
if ((long ) mh.invoke(LARGE, SMALL) != (long ) SMALL) {
fail();
}
// int -> short
try {
if ((short ) mh.invokeExact(LARGE, SMALL) != (short ) SMALL) {}
fail();
} catch (WrongMethodTypeException e) {}
try {
if ((short ) mh.invoke(LARGE, SMALL) != (short ) SMALL) {
fail();
}
} catch (WrongMethodTypeException e) {}
// int -> Integer
try {
if (!((Integer) mh.invokeExact(LARGE, SMALL)).equals(new Integer(SMALL))) {}
fail();
} catch (WrongMethodTypeException e) {}
if (!((Integer) mh.invoke(LARGE, SMALL)).equals(new Integer(SMALL))) {
fail();
}
// int -> Long
try {
Long l = (Long ) mh.invokeExact(LARGE, SMALL);
fail();
} catch (WrongMethodTypeException e) {}
try {
Long l = (Long ) mh.invoke(LARGE, SMALL);
fail();
} catch (WrongMethodTypeException e) {}
// int -> Short
try {
Short s = (Short ) mh.invokeExact(LARGE, SMALL);
fail();
} catch (WrongMethodTypeException e) {}
try {
Short s = (Short ) mh.invoke(LARGE, SMALL);
fail();
} catch (WrongMethodTypeException e) {}
// int -> Process
try {
Process p = (Process) mh.invokeExact(LARGE, SMALL);
fail();
} catch (WrongMethodTypeException e) {}
try {
Process p = (Process) mh.invoke(LARGE, SMALL);
fail();
} catch (WrongMethodTypeException e) {}
// void -> Object
mh = MethodHandles.lookup().findStatic(System.class , "gc" , MethodType.methodType(void .class ));
Object o = (Object) mh.invoke();
if (o != null ) fail();
// void -> long
long l = (long ) mh.invoke();
if (l != 0 ) fail();
// boolean -> Boolean
mh = MethodHandles.lookup().findStatic(Boolean .class , "parseBoolean" ,
MethodType.methodType(boolean .class , String.class ));
Boolean z = (Boolean ) mh.invoke("True" );
if (!z.booleanValue()) fail();
// boolean -> int
try {
int unexpectedValue = (int ) mh.invoke("True" );
fail();
} catch (WrongMethodTypeException e) {}
// boolean -> Integer
try {
Integer unexpectedValue = (Integer) mh.invoke("True" );
fail();
} catch (WrongMethodTypeException e) {}
// Boolean -> boolean
mh = MethodHandles.lookup().findStatic(Boolean .class , "valueOf" ,
MethodType.methodType(Boolean .class , boolean .class ));
boolean w = (boolean ) mh.invoke(false );
if (w) fail();
// Boolean -> int
try {
int unexpectedValue = (int ) mh.invoke(false );
fail();
} catch (WrongMethodTypeException e) {}
// Boolean -> Integer
try {
Integer unexpectedValue = (Integer) mh.invoke("True" );
fail();
} catch (WrongMethodTypeException e) {}
System.out.println("testPrimitiveReturnValueConversions done." );
}
public static void testReturnValueConversions() throws Throwable {
testReferenceReturnValueConversions();
testPrimitiveReturnValueConversions();
}
public static class BaseVariableArityTester {
public String update(Float f0, Float ... floats) {
return "base " + f0 + ", " + Arrays.toString(floats);
}
}
public static class VariableArityTester extends BaseVariableArityTester {
private String lastResult;
// Constructors
public VariableArityTester() {}
public VariableArityTester(boolean ... booleans) { update(booleans); }
public VariableArityTester(byte ... bytes) { update(bytes); }
public VariableArityTester(char ... chars) { update(chars); }
public VariableArityTester(short ... shorts) { update(shorts); }
public VariableArityTester(int ... ints) { update(ints); }
public VariableArityTester(long ... longs) { update(longs); }
public VariableArityTester(float ... floats) { update(floats); }
public VariableArityTester(double ... doubles) { update(doubles); }
public VariableArityTester(Float f0, Float ... floats) { update(f0, floats); }
public VariableArityTester(String s0, String... strings) { update(s0, strings); }
public VariableArityTester(char c, Number... numbers) { update(c, numbers); }
@SafeVarargs
public VariableArityTester(ArrayList<Integer> l0, ArrayList<Integer>... lists) {
update(l0, lists);
}
public VariableArityTester(List l0, List... lists) { update(l0, lists); }
// Methods
public String update(boolean ... booleans) { return lastResult = tally(booleans); }
public String update(byte ... bytes) { return lastResult = tally(bytes); }
public String update(char ... chars) { return lastResult = tally(chars); }
public String update(short ... shorts) { return lastResult = tally(shorts); }
public String update(int ... ints) {
lastResult = tally(ints);
return lastResult;
}
public String update(long ... longs) { return lastResult = tally(longs); }
public String update(float ... floats) { return lastResult = tally(floats); }
public String update(double ... doubles) { return lastResult = tally(doubles); }
@Override
public String update(Float f0, Float ... floats) { return lastResult = tally(f0, floats); }
public String update(String s0, String... strings) { return lastResult = tally(s0, strings); }
public String update(char c, Number... numbers) { return lastResult = tally(c, numbers); }
@SafeVarargs
public final String update(ArrayList<Integer> l0, ArrayList<Integer>... lists) {
lastResult = tally(l0, lists);
return lastResult;
}
public String update(List l0, List... lists) { return lastResult = tally(l0, lists); }
public String arrayMethod(Object[] o) {
return Arrays.deepToString(o);
}
public String lastResult() { return lastResult; }
// Static Methods
public static String tally(boolean ... booleans) { return Arrays.toString(booleans); }
public static String tally(byte ... bytes) { return Arrays.toString(bytes); }
public static String tally(char ... chars) { return Arrays.toString(chars); }
public static String tally(short ... shorts) { return Arrays.toString(shorts); }
public static String tally(int ... ints) { return Arrays.toString(ints); }
public static String tally(long ... longs) { return Arrays.toString(longs); }
public static String tally(float ... floats) { return Arrays.toString(floats); }
public static String tally(double ... doubles) { return Arrays.toString(doubles); }
public static String tally(Float f0, Float ... floats) {
return f0 + ", " + Arrays.toString(floats);
}
public static String tally(String s0, String... strings) {
return s0 + ", " + Arrays.toString(strings);
}
public static String tally(char c, Number... numbers) {
return c + ", " + Arrays.toString(numbers);
}
@SafeVarargs
public static String tally(ArrayList<Integer> l0, ArrayList<Integer>... lists) {
return Arrays.toString(l0.toArray()) + ", " + Arrays.deepToString(lists);
}
public static String tally(List l0, List... lists) {
return Arrays.deepToString(l0.toArray()) + ", " + Arrays.deepToString(lists);
}
public static void foo(int ... ints) { System.out.println(Arrays.toString(ints)); }
public static long sumToPrimitive(int ... ints) {
long result = 0 ;
for (int i : ints) result += i;
return result;
}
public static Long sumToReference(int ... ints) {
System.out.println("Hi" );
return new Long (sumToPrimitive(ints));
}
public static MethodHandles.Lookup lookup() {
return MethodHandles.lookup();
}
}
// This method only exists to fool Jack's handling of types. See b/32536744.
public static Object getAsObject(String[] strings) {
return (Object) strings;
}
public static void testVariableArity() throws Throwable {
MethodHandle mh;
VariableArityTester vat = new VariableArityTester();
assertEquals("[1]" , vat.update(1 ));
assertEquals("[1, 1]" , vat.update(1 , 1 ));
assertEquals("[1, 1, 1]" , vat.update(1 , 1 , 1 ));
// Methods - boolean
mh = MethodHandles.lookup().findVirtual(VariableArityTester.class , "update" ,
MethodType.methodType(String.class , boolean [].class ));
assertTrue(mh.isVarargsCollector());
assertFalse(mh.asFixedArity().isVarargsCollector());
assertEquals("[]" , mh.invoke(vat));
assertEquals("[true, false, true]" , mh.invoke(vat, true , false , true ));
assertEquals("[true, false, true]" , mh.invoke(vat, new boolean [] { true , false , true }));
assertEquals("[false, true]" , mh.invoke(vat, Boolean .valueOf(false ), Boolean .valueOf(true )));
try {
mh.invoke(vat, true , true , 0 );
fail();
} catch (WrongMethodTypeException e) {}
try {
assertEquals("[false, true]" , mh.invoke(vat, Boolean .valueOf(false ), (Boolean ) null ));
fail();
} catch (NullPointerException e) {}
// Methods - byte
mh = MethodHandles.lookup().findVirtual(VariableArityTester.class , "update" ,
MethodType.methodType(String.class , byte [].class ));
assertTrue(mh.isVarargsCollector());
assertEquals("[]" , mh.invoke(vat));
assertEquals("[32, 64, 97]" , mh.invoke(vat, (byte ) 32 , Byte .valueOf((byte ) 64 ), (byte ) 97 ));
assertEquals("[32, 64, 97]" , mh.invoke(vat, new byte [] {(byte ) 32 , (byte ) 64 , (byte ) 97 }));
try {
mh.invoke(vat, (byte ) 1 , Integer.valueOf(3 ), (byte ) 0 );
fail();
} catch (WrongMethodTypeException e) {}
// Methods - char
mh = MethodHandles.lookup().findVirtual(VariableArityTester.class , "update" ,
MethodType.methodType(String.class , char [].class ));
assertTrue(mh.isVarargsCollector());
assertEquals("[]" , mh.invoke(vat));
assertEquals("[A, B, C]" , mh.invoke(vat, 'A' , Character.valueOf('B' ), 'C' ));
assertEquals("[W, X, Y, Z]" , mh.invoke(vat, new char [] { 'W' , 'X' , 'Y' , 'Z' }));
// Methods - short
mh = MethodHandles.lookup().findVirtual(VariableArityTester.class , "update" ,
MethodType.methodType(String.class , short [].class ));
assertTrue(mh.isVarargsCollector());
assertEquals("[]" , mh.invoke(vat));
assertEquals("[32767, -32768, 0]" ,
mh.invoke(vat, Short .MAX_VALUE, Short .MIN_VALUE, Short .valueOf((short ) 0 )));
assertEquals("[1, -1]" , mh.invoke(vat, new short [] { (short ) 1 , (short ) -1 }));
// Methods - int
mh = MethodHandles.lookup().findVirtual(VariableArityTester.class , "update" ,
MethodType.methodType(String.class , int [].class ));
assertTrue(mh.isVarargsCollector());
assertEquals("[]" , mh.invoke(vat));
assertEquals("[0, 2147483647, -2147483648, 0]" ,
mh.invoke(vat, Integer.valueOf(0 ), Integer.MAX_VALUE, Integer.MIN_VALUE, 0 ));
assertEquals("[0, -1, 1, 0]" , mh.invoke(vat, new int [] { 0 , -1 , 1 , 0 }));
assertEquals("[5, 4, 3, 2, 1]" , (String) mh.invokeExact(vat, new int [] { 5 , 4 , 3 , 2 , 1 }));
try {
assertEquals("[5, 4, 3, 2, 1]" , (String) mh.invokeExact(vat, 5 , 4 , 3 , 2 , 1 ));
fail();
} catch (WrongMethodTypeException e) {}
assertEquals("[5, 4, 3, 2, 1]" , (String) mh.invoke(vat, 5 , 4 , 3 , 2 , 1 ));
// Methods - long
mh = MethodHandles.lookup().findVirtual(VariableArityTester.class , "update" ,
MethodType.methodType(String.class , long [].class ));
assertTrue(mh.isVarargsCollector());
assertEquals("[]" , mh.invoke(vat));
assertEquals("[0, 9223372036854775807, -9223372036854775808]" ,
mh.invoke(vat, Long .valueOf(0 ), Long .MAX_VALUE, Long .MIN_VALUE));
assertEquals("[0, -1, 1, 0]" , mh.invoke(vat, new long [] { 0 , -1 , 1 , 0 }));
// Methods - float
mh = MethodHandles.lookup().findVirtual(VariableArityTester.class , "update" ,
MethodType.methodType(String.class , float [].class ));
assertTrue(mh.isVarargsCollector());
assertEquals("[]" , mh.invoke(vat));
assertEquals("[0.0, 1.25, -1.25]" ,
mh.invoke(vat, 0 .0 f, Float .valueOf(1 .25 f), Float .valueOf(-1 .25 f)));
assertEquals("[0.0, -1.0, 1.0, 0.0]" ,
mh.invoke(vat, new float [] { 0 .0 f, -1 .0 f, 1 .0 f, 0 .0 f }));
// Methods - double
mh = MethodHandles.lookup().findVirtual(VariableArityTester.class , "update" ,
MethodType.methodType(String.class , double [].class ));
assertTrue(mh.isVarargsCollector());
assertEquals("[]" , mh.invoke(vat));
assertEquals("[0.0, 1.25, -1.25]" ,
mh.invoke(vat, 0 .0 , Double .valueOf(1 .25 ), Double .valueOf(-1 .25 )));
assertEquals("[0.0, -1.0, 1.0, 0.0]" ,
mh.invoke(vat, new double [] { 0 .0 , -1 .0 , 1 .0 , 0 .0 }));
mh.invoke(vat, 0 .3 f, 1 .33 , 1 .33 );
// Methods - String
mh = MethodHandles.lookup().
findVirtual(VariableArityTester.class , "update" ,
MethodType.methodType(String.class , String.class , String[].class ));
assertTrue(mh.isVarargsCollector());
assertEquals("Echidna, []" , mh.invoke(vat, "Echidna" ));
assertEquals("Bongo, [Jerboa, Okapi]" ,
mh.invoke(vat, "Bongo" , "Jerboa" , "Okapi" ));
// Methods - Float
mh = MethodHandles.lookup().
findVirtual(VariableArityTester.class , "update" ,
MethodType.methodType(String.class , Float .class , Float [].class ));
assertTrue(mh.isVarargsCollector());
assertEquals("9.99, [0.0, 0.1, 1.1]" ,
(String) mh.invoke(vat, Float .valueOf(9 .99 f),
new Float [] { Float .valueOf(0 .0 f),
Float .valueOf(0 .1 f),
Float .valueOf(1 .1 f) }));
assertEquals("9.99, [0.0, 0.1, 1.1]" ,
(String) mh.invoke(vat, Float .valueOf(9 .99 f), Float .valueOf(0 .0 f),
Float .valueOf(0 .1 f), Float .valueOf(1 .1 f)));
assertEquals("9.99, [0.0, 0.1, 1.1]" ,
(String) mh.invoke(vat, Float .valueOf(9 .99 f), 0 .0 f, 0 .1 f, 1 .1 f));
try {
assertEquals("9.99, [77.0, 33.0, 64.0]" ,
(String) mh.invoke(vat, Float .valueOf(9 .99 f), 77 , 33 , 64 ));
fail();
} catch (WrongMethodTypeException e) {}
assertEquals("9.99, [0.0, 0.1, 1.1]" ,
(String) mh.invokeExact(vat, Float .valueOf(9 .99 f),
new Float [] { Float .valueOf(0 .0 f),
Float .valueOf(0 .1 f),
Float .valueOf(1 .1 f) }));
assertEquals("9.99, [0.0, null, 1.1]" ,
(String) mh.invokeExact(vat, Float .valueOf(9 .99 f),
new Float [] { Float .valueOf(0 .0 f),
null ,
Float .valueOf(1 .1 f) }));
try {
assertEquals("9.99, [0.0, 0.1, 1.1]" ,
(String) mh.invokeExact(vat, Float .valueOf(9 .99 f), 0 .0 f, 0 .1 f, 1 .1 f));
fail();
} catch (WrongMethodTypeException e) {}
// Methods - Number
mh = MethodHandles.lookup().
findVirtual(VariableArityTester.class , "update" ,
MethodType.methodType(String.class , char .class , Number[].class ));
assertTrue(mh.isVarargsCollector());
assertFalse(mh.asFixedArity().isVarargsCollector());
assertEquals("x, []" , (String) mh.invoke(vat, 'x' ));
assertEquals("x, [3.141]" , (String) mh.invoke(vat, 'x' , 3 .141 ));
assertEquals("x, [null, 3.131, 37]" ,
(String) mh.invoke(vat, 'x' , null , 3 .131 , new Integer(37 )));
try {
assertEquals("x, [null, 3.131, bad, 37]" ,
(String) mh.invoke(vat, 'x' , null , 3 .131 , "bad" , new Integer(37 )));
assertTrue(false );
fail();
} catch (ClassCastException e) {}
try {
assertEquals("x, [null, 3.131, bad, 37]" ,
(String) mh.invoke(
vat, 'x' , (Process) null , 3 .131 , "bad" , new Integer(37 )));
assertTrue(false );
fail();
} catch (ClassCastException e) {}
// Methods - an array method that is not variable arity.
mh = MethodHandles.lookup().findVirtual(
VariableArityTester.class , "arrayMethod" ,
MethodType.methodType(String.class , Object[].class ));
assertFalse(mh.isVarargsCollector());
mh.invoke(vat, new Object[] { "123" });
try {
assertEquals("-" , mh.invoke(vat, new Float (3 ), new Float (4 )));
fail();
} catch (WrongMethodTypeException e) {}
mh = mh.asVarargsCollector(Object[].class );
assertTrue(mh.isVarargsCollector());
assertEquals("[3.0, 4.0]" , (String) mh.invoke(vat, new Float (3 ), new Float (4 )));
// Constructors - default
mh = MethodHandles.lookup().findConstructor(
VariableArityTester.class , MethodType.methodType(void .class ));
assertFalse(mh.isVarargsCollector());
// Constructors - boolean
mh = MethodHandles.lookup().findConstructor(
VariableArityTester.class , MethodType.methodType(void .class , boolean [].class ));
assertTrue(mh.isVarargsCollector());
assertEquals("[true, true, false]" ,
((VariableArityTester) mh.invoke(new boolean [] {true , true , false })).lastResult());
assertEquals("[true, true, false]" ,
((VariableArityTester) mh.invoke(true , true , false )).lastResult());
try {
assertEquals("[true, true, false]" ,
((VariableArityTester) mh.invokeExact(true , true , false )).lastResult());
fail();
} catch (WrongMethodTypeException e) {}
// Constructors - byte
mh = MethodHandles.lookup().findConstructor(
VariableArityTester.class , MethodType.methodType(void .class , byte [].class ));
assertTrue(mh.isVarargsCollector());
assertEquals("[55, 66, 60]" ,
((VariableArityTester)
mh.invoke(new byte [] {(byte ) 55 , (byte ) 66 , (byte ) 60 })).lastResult());
assertEquals("[55, 66, 60]" ,
((VariableArityTester) mh.invoke(
(byte ) 55 , (byte ) 66 , (byte ) 60 )).lastResult());
try {
assertEquals("[55, 66, 60]" ,
((VariableArityTester) mh.invokeExact(
(byte ) 55 , (byte ) 66 , (byte ) 60 )).lastResult());
fail();
} catch (WrongMethodTypeException e) {}
try {
assertEquals("[3, 3]" ,
((VariableArityTester) mh.invoke(
new Number[] { Byte .valueOf((byte ) 3 ), (byte ) 3 })).lastResult());
fail();
} catch (WrongMethodTypeException e) {}
// Constructors - String (have a different path than other reference types).
mh = MethodHandles.lookup().findConstructor(
VariableArityTester.class , MethodType.methodType(void .class , String.class , String[].class ));
assertTrue(mh.isVarargsCollector());
assertEquals("x, []" , ((VariableArityTester) mh.invoke("x" )).lastResult());
assertEquals("x, [y]" , ((VariableArityTester) mh.invoke("x" , "y" )).lastResult());
assertEquals("x, [y, z]" ,
((VariableArityTester) mh.invoke("x" , new String[] { "y" , "z" })).lastResult());
try {
assertEquals("x, [y]" , ((VariableArityTester) mh.invokeExact("x" , "y" )).lastResult());
fail();
} catch (WrongMethodTypeException e) {}
assertEquals("x, [null, z]" ,
((VariableArityTester) mh.invoke("x" , new String[] { null , "z" })).lastResult());
// Constructors - Number
mh = MethodHandles.lookup().findConstructor(
VariableArityTester.class , MethodType.methodType(void .class , char .class , Number[].class ));
assertTrue(mh.isVarargsCollector());
assertFalse(mh.asFixedArity().isVarargsCollector());
assertEquals("x, []" , ((VariableArityTester) mh.invoke('x' )).lastResult());
assertEquals("x, [3.141]" , ((VariableArityTester) mh.invoke('x' , 3 .141 )).lastResult());
assertEquals("x, [null, 3.131, 37]" ,
((VariableArityTester) mh.invoke('x' , null , 3 .131 , new Integer(37 ))).lastResult());
try {
assertEquals("x, [null, 3.131, bad, 37]" ,
((VariableArityTester) mh.invoke(
'x' , null , 3 .131 , "bad" , new Integer(37 ))).lastResult());
assertTrue(false );
fail();
} catch (ClassCastException e) {}
try {
assertEquals("x, [null, 3.131, bad, 37]" ,
((VariableArityTester) mh.invoke(
'x' , (Process) null , 3 .131 , "bad" , new Integer(37 ))).lastResult());
assertTrue(false );
fail();
} catch (ClassCastException e) {}
// Static Methods - Float
mh = MethodHandles.lookup().
findStatic(VariableArityTester.class , "tally" ,
MethodType.methodType(String.class , Float .class , Float [].class ));
assertTrue(mh.isVarargsCollector());
assertEquals("9.99, [0.0, 0.1, 1.1]" ,
(String) mh.invoke(Float .valueOf(9 .99 f),
new Float [] { Float .valueOf(0 .0 f),
Float .valueOf(0 .1 f),
Float .valueOf(1 .1 f) }));
assertEquals("9.99, [0.0, 0.1, 1.1]" ,
(String) mh.invoke(Float .valueOf(9 .99 f), Float .valueOf(0 .0 f),
Float .valueOf(0 .1 f), Float .valueOf(1 .1 f)));
assertEquals("9.99, [0.0, 0.1, 1.1]" ,
(String) mh.invoke(Float .valueOf(9 .99 f), 0 .0 f, 0 .1 f, 1 .1 f));
try {
assertEquals("9.99, [77.0, 33.0, 64.0]" ,
(String) mh.invoke(Float .valueOf(9 .99 f), 77 , 33 , 64 ));
fail();
} catch (WrongMethodTypeException e) {}
assertEquals("9.99, [0.0, 0.1, 1.1]" ,
(String) mh.invokeExact(Float .valueOf(9 .99 f),
new Float [] { Float .valueOf(0 .0 f),
Float .valueOf(0 .1 f),
Float .valueOf(1 .1 f) }));
assertEquals("9.99, [0.0, null, 1.1]" ,
(String) mh.invokeExact(Float .valueOf(9 .99 f),
new Float [] { Float .valueOf(0 .0 f),
null ,
Float .valueOf(1 .1 f) }));
try {
assertEquals("9.99, [0.0, 0.1, 1.1]" ,
(String) mh.invokeExact(Float .valueOf(9 .99 f), 0 .0 f, 0 .1 f, 1 .1 f));
fail();
} catch (WrongMethodTypeException e) {}
// Special methods - Float
mh = VariableArityTester.lookup().
findSpecial(BaseVariableArityTester.class , "update" ,
MethodType.methodType(String.class , Float .class , Float [].class ),
VariableArityTester.class );
assertTrue(mh.isVarargsCollector());
assertEquals("base 9.99, [0.0, 0.1, 1.1]" ,
(String) mh.invoke(vat,
Float .valueOf(9 .99 f),
new Float [] { Float .valueOf(0 .0 f),
Float .valueOf(0 .1 f),
Float .valueOf(1 .1 f) }));
assertEquals("base 9.99, [0.0, 0.1, 1.1]" ,
(String) mh.invoke(vat, Float .valueOf(9 .99 f), Float .valueOf(0 .0 f),
Float .valueOf(0 .1 f), Float .valueOf(1 .1 f)));
// Return value conversions.
mh = MethodHandles.lookup().findVirtual(VariableArityTester.class , "update" ,
MethodType.methodType(String.class , int [].class ));
assertEquals("[1, 2, 3]" , (String) mh.invoke(vat, 1 , 2 , 3 ));
assertEquals("[1, 2, 3]" , (Object) mh.invoke(vat, 1 , 2 , 3 ));
try {
assertEquals("[1, 2, 3, 4]" , (long ) mh.invoke(vat, 1 , 2 , 3 ));
fail();
} catch (WrongMethodTypeException e) {}
assertEquals("[1, 2, 3]" , vat.lastResult());
mh = MethodHandles.lookup().findStatic(VariableArityTester.class , "sumToPrimitive" ,
MethodType.methodType(long .class , int [].class ));
assertEquals(10 l, (long ) mh.invoke(1 , 2 , 3 , 4 ));
assertEquals(Long .valueOf(10 l), (Long ) mh.invoke(1 , 2 , 3 , 4 ));
mh = MethodHandles.lookup().findStatic(VariableArityTester.class , "sumToReference" ,
MethodType.methodType(Long .class , int [].class ));
Object o = mh.invoke(1 , 2 , 3 , 4 );
long l = (long ) mh.invoke(1 , 2 , 3 , 4 );
assertEquals(10 l, (long ) mh.invoke(1 , 2 , 3 , 4 ));
assertEquals(Long .valueOf(10 l), (Long ) mh.invoke(1 , 2 , 3 , 4 ));
try {
// WrongMethodTypeException should be raised before invoke here.
System.out.print("Expect Hi here: " );
assertEquals(Long .valueOf(10 l), (Byte ) mh.invoke(1 , 2 , 3 , 4 ));
fail();
} catch (ClassCastException e) {}
try {
// WrongMethodTypeException should be raised before invoke here.
System.out.println("Don't expect Hi now" );
byte b = (byte ) mh.invoke(1 , 2 , 3 , 4 );
fail();
} catch (WrongMethodTypeException e) {}
// Return void produces 0 / null.
mh = MethodHandles.lookup().findStatic(VariableArityTester.class , "foo" ,
MethodType.methodType(void .class , int [].class ));
assertEquals(null , (Object) mh.invoke(3 , 2 , 1 ));
assertEquals(0 l, (long ) mh.invoke(1 , 2 , 3 ));
// Combinators
mh = MethodHandles.lookup().findVirtual(VariableArityTester.class , "update" ,
MethodType.methodType(String.class , boolean [].class ));
assertTrue(mh.isVarargsCollector());
mh = mh.bindTo(vat);
assertFalse(mh.isVarargsCollector());
mh = mh.asVarargsCollector(boolean [].class );
assertTrue(mh.isVarargsCollector());
assertEquals("[]" , mh.invoke());
assertEquals("[true, false, true]" , mh.invoke(true , false , true ));
assertEquals("[true, false, true]" , mh.invoke(new boolean [] { true , false , true }));
assertEquals("[false, true]" , mh.invoke(Boolean .valueOf(false ), Boolean .valueOf(true )));
try {
mh.invoke(true , true , 0 );
fail();
} catch (WrongMethodTypeException e) {}
}
// The same tests as the above, except that we use use MethodHandles.bind instead of
// MethodHandle.bindTo.
public static void testVariableArity_MethodHandles_bind() throws Throwable {
VariableArityTester vat = new VariableArityTester();
MethodHandle mh = MethodHandles.lookup().bind(vat, "update" ,
MethodType.methodType(String.class , boolean [].class ));
assertTrue(mh.isVarargsCollector());
assertEquals("[]" , mh.invoke());
assertEquals("[true, false, true]" , mh.invoke(true , false , true ));
assertEquals("[true, false, true]" , mh.invoke(new boolean [] { true , false , true }));
assertEquals("[false, true]" , mh.invoke(Boolean .valueOf(false ), Boolean .valueOf(true )));
try {
mh.invoke(true , true , 0 );
fail();
} catch (WrongMethodTypeException e) {}
}
public static void testRevealDirect() throws Throwable {
// Test with a virtual method :
MethodType type = MethodType.methodType(String.class );
MethodHandle handle = MethodHandles.lookup().findVirtual(
UnreflectTester.class , "publicMethod" , type);
// Comparisons with an equivalent member obtained via reflection :
MethodHandleInfo info = MethodHandles.lookup().revealDirect(handle);
Method meth = UnreflectTester.class .getMethod("publicMethod" );
assertEquals(MethodHandleInfo.REF_invokeVirtual, info.getReferenceKind());
assertEquals("publicMethod" , info.getName());
assertTrue(UnreflectTester.class == info.getDeclaringClass());
assertFalse(info.isVarArgs());
assertEquals(meth, info.reflectAs(Method.class , MethodHandles.lookup()));
assertEquals(type, info.getMethodType());
// Resolution via a public lookup should fail because the method in question
// isn't public.
try {
info.reflectAs(Method.class , MethodHandles.publicLookup());
fail();
} catch (IllegalArgumentException expected) {
}
// Test with a static method :
handle = MethodHandles.lookup().findStatic(UnreflectTester.class ,
"publicStaticMethod" ,
MethodType.methodType(String.class ));
info = MethodHandles.lookup().revealDirect(handle);
meth = UnreflectTester.class .getMethod("publicStaticMethod" );
assertEquals(MethodHandleInfo.REF_invokeStatic, info.getReferenceKind());
assertEquals("publicStaticMethod" , info.getName());
assertTrue(UnreflectTester.class == info.getDeclaringClass());
assertFalse(info.isVarArgs());
assertEquals(meth, info.reflectAs(Method.class , MethodHandles.lookup()));
assertEquals(type, info.getMethodType());
// Test with a var-args method :
type = MethodType.methodType(String.class , String[].class );
handle = MethodHandles.lookup().findVirtual(UnreflectTester.class ,
"publicVarArgsMethod" , type);
info = MethodHandles.lookup().revealDirect(handle);
meth = UnreflectTester.class .getMethod("publicVarArgsMethod" , String[].class );
assertEquals(MethodHandleInfo.REF_invokeVirtual, info.getReferenceKind());
assertEquals("publicVarArgsMethod" , info.getName());
assertTrue(UnreflectTester.class == info.getDeclaringClass());
assertTrue(info.isVarArgs());
assertEquals(meth, info.reflectAs(Method.class , MethodHandles.lookup()));
assertEquals(type, info.getMethodType());
// Test with a constructor :
Constructor cons = UnreflectTester.class .getConstructor(String.class , boolean .class );
type = MethodType.methodType(void .class , String.class , boolean .class );
handle = MethodHandles.lookup().findConstructor(UnreflectTester.class , type);
info = MethodHandles.lookup().revealDirect(handle);
assertEquals(MethodHandleInfo.REF_newInvokeSpecial, info.getReferenceKind());
assertEquals("<init>" , info.getName());
assertTrue(UnreflectTester.class == info.getDeclaringClass());
assertFalse(info.isVarArgs());
assertEquals(cons, info.reflectAs(Constructor.class , MethodHandles.lookup()));
assertEquals(type, info.getMethodType());
// Test with a static field :
Field field = UnreflectTester.class .getField("publicStaticField" );
handle = MethodHandles.lookup().findStaticSetter(
UnreflectTester.class , "publicStaticField" , String.class );
info = MethodHandles.lookup().revealDirect(handle);
assertEquals(MethodHandleInfo.REF_putStatic, info.getReferenceKind());
assertEquals("publicStaticField" , info.getName());
assertTrue(UnreflectTester.class == info.getDeclaringClass());
assertFalse(info.isVarArgs());
assertEquals(field, info.reflectAs(Field.class , MethodHandles.lookup()));
assertEquals(MethodType.methodType(void .class , String.class ), info.getMethodType());
// Test with a setter on the same field, the type of the handle should change
// but everything else must remain the same.
handle = MethodHandles.lookup().findStaticGetter(
UnreflectTester.class , "publicStaticField" , String.class );
info = MethodHandles.lookup().revealDirect(handle);
assertEquals(MethodHandleInfo.REF_getStatic, info.getReferenceKind());
assertEquals(field, info.reflectAs(Field.class , MethodHandles.lookup()));
assertEquals(MethodType.methodType(String.class ), info.getMethodType());
// Test with an instance field :
field = UnreflectTester.class .getField("publicField" );
handle = MethodHandles.lookup().findSetter(
UnreflectTester.class , "publicField" , String.class );
info = MethodHandles.lookup().revealDirect(handle);
assertEquals(MethodHandleInfo.REF_putField, info.getReferenceKind());
assertEquals("publicField" , info.getName());
assertTrue(UnreflectTester.class == info.getDeclaringClass());
assertFalse(info.isVarArgs());
assertEquals(field, info.reflectAs(Field.class , MethodHandles.lookup()));
assertEquals(MethodType.methodType(void .class , String.class ), info.getMethodType());
// Test with a setter on the same field, the type of the handle should change
// but everything else must remain the same.
handle = MethodHandles.lookup().findGetter(
UnreflectTester.class , "publicField" , String.class );
info = MethodHandles.lookup().revealDirect(handle);
assertEquals(MethodHandleInfo.REF_getField, info.getReferenceKind());
assertEquals(field, info.reflectAs(Field.class , MethodHandles.lookup()));
assertEquals(MethodType.methodType(String.class ), info.getMethodType());
}
public static void testReflectiveCalls() throws Throwable {
String[] methodNames = { "invoke" , "invokeExact" };
for (String methodName : methodNames) {
Method invokeMethod = MethodHandle.class .getMethod(methodName, Object[].class );
MethodHandle instance =
MethodHandles.lookup().findVirtual(java.io.PrintStream.class , "println" ,
MethodType.methodType(void .class , String.class ));
try {
invokeMethod.invoke(instance, new Object[] { new Object[] { Integer.valueOf(1 ) } } );
fail();
} catch (InvocationTargetException ite) {
assertEquals(ite.getCause().getClass(), UnsupportedOperationException.class );
}
}
}
public static void testInterfaceSpecial() throws Throwable {
final Method acceptMethod = Consumer.class .getDeclaredMethod("accept" , Object.class );
final Method andThenMethod = Consumer.class .getDeclaredMethod("andThen" , Consumer.class );
// Proxies
Consumer<Object> c = (Consumer<Object>)Proxy.newProxyInstance(
Main.class .getClassLoader(),
new Class <?>[] { Consumer.class },
(p, m, a) -> {
System.out.println("Trying to call " + m);
if (m.equals(andThenMethod)) {
List<Object> args = a == null ? Collections.EMPTY_LIST : Arrays.asList(a);
return MethodHandles.lookup()
.findSpecial(Consumer.class ,
m.getName(),
MethodType.methodType(m.getReturnType(),
m.getParameterTypes()),
p.getClass())
.bindTo(p)
.invokeWithArguments(args);
} else if (m.equals(acceptMethod)) {
System.out.println("Called accept with " + a[0 ]);
}
return null ;
});
c.accept("foo" );
Consumer<Object> c2 = c.andThen((Object o) -> { System.out.println("and then " + o); });
c2.accept("bar" );
// Non-proxies
Consumer<Object> c3 = new Consumer() {
public void accept(Object o) {
System.out.println("Got " + o);
}
@Override
public Consumer<Object> andThen(Consumer c) {
System.out.println("Ignoring and then" );
return this ;
}
};
Consumer<Object> c4 = c3.andThen((x) -> { throw new Error("Failed" ); });
c4.accept("hello" );
Consumer<Object> andthen = (Object o) -> { System.out.println("Called and then with " + o);};
Consumer<Object> c5 =
(Consumer<Object>)MethodHandles.lookup()
.findSpecial(Consumer.class ,
andThenMethod.getName(),
MethodType.methodType(
andThenMethod.getReturnType(),
andThenMethod.getParameterTypes()),
c3.getClass())
.bindTo(c3)
.invoke(andthen);
c5.accept("hello there" );
// Failures
try {
MethodHandles.lookup()
.findSpecial(Consumer.class ,
acceptMethod.getName(),
MethodType.methodType(acceptMethod.getReturnType(),
acceptMethod.getParameterTypes()),
c3.getClass());
} catch (IllegalAccessException e) {
System.out.println("Got expected IAE when invoke-special on an abstract interface method" );
}
}
private static int returnInput(int value) { return value; }
private static byte returnInput(byte value) { return value; }
private static char returnInput(char value) { return value; }
private static void testFastInvoke() throws Throwable {
// This tests use of invoke() that have different types and require widening, but do not
// require require an explicit asType() transform.
MethodHandle mh0 =
MethodHandles.lookup().findStatic(
Main.class , "returnInput" , MethodType.methodType(int .class , int .class ));
assertEquals((byte ) 127 , (byte ) (int ) mh0.invoke((byte ) 127 ));
assertEquals((byte ) -128 , (byte ) (int ) mh0.invoke((byte ) -128 ));
assertEquals((short ) 127 , (short ) (int ) mh0.invoke((byte ) 127 ));
assertEquals((short ) -128 , (short ) (int ) mh0.invoke((byte ) -128 ));
assertEquals((char ) 127 , (char ) (int ) mh0.invoke((byte ) 127 ));
assertEquals((char ) 65535 , (char ) (int ) mh0.invoke((byte ) -1 ));
assertEquals((char ) 0 , (char ) (int ) mh0.invoke((char ) 0 ));
assertEquals((char ) 65535 , (char ) (int ) mh0.invoke((char ) 65535 ));
assertEquals((short ) 127 , (short ) (int ) mh0.invoke((short ) 127 ));
assertEquals((short ) -128 , (short ) (int ) mh0.invoke((short ) -128 ));
assertEquals((int ) 127 , (int ) mh0.invoke((byte ) 127 ));
assertEquals((int ) -128 , (int ) mh0.invoke((byte ) -128 ));
assertEquals((int ) 127 , (int ) mh0.invoke((short ) 127 ));
assertEquals((int ) -128 , (int ) mh0.invoke((short ) -128 ));
assertEquals((int ) 0 , (int ) mh0.invoke((char ) 0 ));
assertEquals((int ) 65535 , (int ) mh0.invoke((char ) 65535 ));
MethodHandle mh1 =
MethodHandles.lookup().findStatic(
Main.class , "returnInput" , MethodType.methodType(char .class , char .class ));
assertEquals((int ) 0 , (int ) mh1.invoke((char ) 0 ));
assertEquals((int ) 65535 , (int ) mh1.invoke((char ) 65535 ));
MethodHandle mh2 =
MethodHandles.lookup().findStatic(
Main.class , "returnInput" , MethodType.methodType(byte .class , byte .class ));
assertEquals((int ) -128 , (int ) mh2.invoke((byte ) -128 ));
assertEquals((int ) 127 , (int ) mh2.invoke((byte ) 127 ));
assertEquals((short ) -128 , (short ) mh2.invoke((byte ) -128 ));
assertEquals((short ) 127 , (short ) mh2.invoke((byte ) 127 ));
}
}
Messung V0.5 in Prozent C=88 H=96 G=91
¤ Dauer der Verarbeitung: 0.29 Sekunden
(vorverarbeitet am 2026-06-29)
¤
*© Formatika GbR, Deutschland