下面列出了怎么用java.lang.invoke.LambdaMetafactory的API类实例代码及写法,或者点击链接到github查看源代码。
public static CallSite lambdaCapture(
MethodHandles.Lookup callerLookup,
String name,
MethodType type,
MethodType samMethodType,
MethodHandle implMethod,
MethodType instantiatedMethodType)
{
try {
// delegate to metafactory, we may choose to generate code ourselves in the future.
return LambdaMetafactory.metafactory(
callerLookup,
name,
type,
samMethodType,
implMethod,
instantiatedMethodType);
}
catch (LambdaConversionException e) {
throwIfUnchecked(e);
throw new RuntimeException(e);
}
}
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");
}
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, LambdaReceiverBridge.class);
MethodType A = mt(int.class, LambdaReceiver_A.class);
MethodType mti = mt(IA.class);
CallSite cs = LambdaMetafactory.altMetafactory(l, "m", mti,X,h,X,
LambdaMetafactory.FLAG_BRIDGES, 1, A);
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");
}
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");
}
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, LambdaReceiverBridge.class);
MethodType A = mt(int.class, LambdaReceiver_A.class);
MethodType mti = mt(IA.class);
CallSite cs = LambdaMetafactory.altMetafactory(l, "m", mti,X,h,X,
LambdaMetafactory.FLAG_BRIDGES, 1, A);
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");
}
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");
}
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, LambdaReceiverBridge.class);
MethodType A = mt(int.class, LambdaReceiver_A.class);
MethodType mti = mt(IA.class);
CallSite cs = LambdaMetafactory.altMetafactory(l, "m", mti,X,h,X,
LambdaMetafactory.FLAG_BRIDGES, 1, A);
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");
}
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");
}
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, LambdaReceiverBridge.class);
MethodType A = mt(int.class, LambdaReceiver_A.class);
MethodType mti = mt(IA.class);
CallSite cs = LambdaMetafactory.altMetafactory(l, "m", mti,X,h,X,
LambdaMetafactory.FLAG_BRIDGES, 1, A);
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");
}
public T build() {
try {
MethodHandle targetMethodHandle = targetMethod.map(
m -> invokeSafely(() -> LOOKUP.unreflect(m)),
c -> invokeSafely(() -> LOOKUP.unreflectConstructor(c)));
return lambdaType.cast(
LambdaMetafactory.metafactory(LOOKUP,
lambdaMethodName,
MethodType.methodType(lambdaType),
MethodType.methodType(postEraseLambdaReturnType, postEraseLambdaParameters),
targetMethodHandle,
MethodType.methodType(preEraseLambdaReturnType, preEraseLambdaParameters))
.getTarget()
.invoke());
} catch (Throwable e) {
throw new IllegalArgumentException("Failed to generate method handle.", e);
}
}
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");
}
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, LambdaReceiverBridge.class);
MethodType A = mt(int.class, LambdaReceiver_A.class);
MethodType mti = mt(IA.class);
CallSite cs = LambdaMetafactory.altMetafactory(l, "m", mti,X,h,X,
LambdaMetafactory.FLAG_BRIDGES, 1, A);
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");
}
@SuppressWarnings("unchecked")
public static <T> T createLambda(Object instance, Method instanceMethod, Class<?> functionalIntfCls) {
try {
Method intfMethod = findAbstractMethod(functionalIntfCls);
MethodHandle methodHandle = LOOKUP.unreflect(instanceMethod);
MethodType intfMethodType = MethodType.methodType(intfMethod.getReturnType(), intfMethod.getParameterTypes());
MethodType instanceMethodType = MethodType
.methodType(instanceMethod.getReturnType(), instanceMethod.getParameterTypes());
CallSite callSite = LambdaMetafactory.metafactory(
LOOKUP,
intfMethod.getName(),
MethodType.methodType(functionalIntfCls, instance.getClass()),
intfMethodType,
methodHandle,
instanceMethodType);
return (T) callSite.getTarget().bindTo(instance).invoke();
} catch (Throwable e) {
throw new IllegalStateException("Failed to create lambda from " + instanceMethod, e);
}
}
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");
}
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, LambdaReceiverBridge.class);
MethodType A = mt(int.class, LambdaReceiver_A.class);
MethodType mti = mt(IA.class);
CallSite cs = LambdaMetafactory.altMetafactory(l, "m", mti,X,h,X,
LambdaMetafactory.FLAG_BRIDGES, 1, A);
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");
}
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");
}
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, LambdaReceiverBridge.class);
MethodType A = mt(int.class, LambdaReceiver_A.class);
MethodType mti = mt(IA.class);
CallSite cs = LambdaMetafactory.altMetafactory(l, "m", mti,X,h,X,
LambdaMetafactory.FLAG_BRIDGES, 1, A);
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");
}
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");
}
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, LambdaReceiverBridge.class);
MethodType A = mt(int.class, LambdaReceiver_A.class);
MethodType mti = mt(IA.class);
CallSite cs = LambdaMetafactory.altMetafactory(l, "m", mti,X,h,X,
LambdaMetafactory.FLAG_BRIDGES, 1, A);
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 static void amf(List<String> errs, MethodHandle h, MethodType mts, MethodType mtf, MethodType mtb, boolean shouldWork) {
MethodType mti = mt(I.class);
try {
LambdaMetafactory.altMetafactory(l, "m", mti, mts,h,mtf,
LambdaMetafactory.FLAG_BRIDGES, 1, mtb);
} catch(LambdaConversionException e) {
if (shouldWork) errs.add("Error: Should work h=" + h + " s=" + mts + " -- f=" + mtf + " / b=" + mtb + " got: " + e);
return;
}
if (!shouldWork) errs.add("Error: Should fail h=" + h + " s=" + mts + " -- f=" + mtf + " / b=" + mtb);
}
private static boolean mf(MethodHandles.Lookup l) {
try {
LambdaMetafactory.metafactory(l, "close",
mt(Closeable.class),mt(void.class),h,mt(void.class));
} catch(LambdaConversionException e) {
return true;
}
return false;
}
private static boolean mf(Class<?> k) {
try {
LambdaMetafactory.metafactory(l, "m",
mt(I.class),mt(k),h,mt(void.class));
} catch(LambdaConversionException e) {
return true;
}
return false;
}
private static boolean mf(MethodType mti, MethodType mtf) {
try {
LambdaMetafactory.metafactory(l, "m", mti,mtf,h,mtf);
} catch(LambdaConversionException e) {
return true;
}
return false;
}
public void testDirectStdNonser() throws Throwable {
MethodHandle fooMH = MethodHandles.lookup().findStatic(SerializedLambdaTest.class, "foo", predicateMT);
// Standard metafactory, non-serializable target: not serializable
CallSite cs = LambdaMetafactory.metafactory(MethodHandles.lookup(),
"test", MethodType.methodType(Predicate.class),
predicateMT, fooMH, stringPredicateMT);
Predicate<String> p = (Predicate<String>) cs.getTarget().invokeExact();
assertNotSerial(p, fooAsserter);
}
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);
}
public void testAltStdNonser() throws Throwable {
MethodHandle fooMH = MethodHandles.lookup().findStatic(SerializedLambdaTest.class, "foo", predicateMT);
// Alt metafactory, non-serializable target: not serializable
CallSite cs = LambdaMetafactory.altMetafactory(MethodHandles.lookup(),
"test", MethodType.methodType(Predicate.class),
predicateMT, fooMH, stringPredicateMT, 0);
assertNotSerial((Predicate<String>) cs.getTarget().invokeExact(), fooAsserter);
}
public void testAltStdSer() throws Throwable {
MethodHandle fooMH = MethodHandles.lookup().findStatic(SerializedLambdaTest.class, "foo", predicateMT);
// Alt metafactory, serializable target, no FLAG_SERIALIZABLE: not serializable
CallSite cs = LambdaMetafactory.altMetafactory(MethodHandles.lookup(),
"test", MethodType.methodType(SerPredicate.class),
predicateMT, fooMH, stringPredicateMT, 0);
assertNotSerial((SerPredicate<String>) cs.getTarget().invokeExact(), fooAsserter);
// Alt metafactory, serializable marker, no FLAG_SERIALIZABLE: not serializable
cs = LambdaMetafactory.altMetafactory(MethodHandles.lookup(),
"test", MethodType.methodType(Predicate.class),
predicateMT, fooMH, stringPredicateMT, LambdaMetafactory.FLAG_MARKERS, 1, Serializable.class);
assertNotSerial((Predicate<String>) cs.getTarget().invokeExact(), fooAsserter);
}
private static void amf(List<String> errs, MethodHandle h, MethodType mts, MethodType mtf, MethodType mtb, boolean shouldWork) {
MethodType mti = mt(I.class);
try {
LambdaMetafactory.altMetafactory(l, "m", mti, mts,h,mtf,
LambdaMetafactory.FLAG_BRIDGES, 1, mtb);
} catch(LambdaConversionException e) {
if (shouldWork) errs.add("Error: Should work h=" + h + " s=" + mts + " -- f=" + mtf + " / b=" + mtb + " got: " + e);
return;
}
if (!shouldWork) errs.add("Error: Should fail h=" + h + " s=" + mts + " -- f=" + mtf + " / b=" + mtb);
}
private static boolean mf(MethodHandles.Lookup l) {
try {
LambdaMetafactory.metafactory(l, "close",
mt(Closeable.class),mt(void.class),h,mt(void.class));
} catch(LambdaConversionException e) {
return true;
}
return false;
}
private static boolean mf(Class<?> k) {
try {
LambdaMetafactory.metafactory(l, "m",
mt(I.class),mt(k),h,mt(void.class));
} catch(LambdaConversionException e) {
return true;
}
return false;
}