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GH-3765 Resolve Lookup ctor lazily via reflection #3781

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Merged
merged 1 commit into from
Apr 11, 2022
Merged

GH-3765 Resolve Lookup ctor lazily via reflection #3781

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55 changes: 31 additions & 24 deletions .../java/org/springframework/integration/gateway/DefaultMethodInvokingMethodInterceptor.java
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright 2015-2021 the original author or authors.
* Copyright 2015-2022 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
Expand All @@ -23,6 +23,7 @@
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.util.Map;
import java.util.function.Supplier;

import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
Expand Down Expand Up @@ -119,29 +120,36 @@ private Lookup getLookup(Class<?> declaringClass, Method privateLookupIn) {
*/
OPEN {

@Nullable
private final transient Constructor<Lookup> constructor;

{
Constructor<Lookup> ctor = null;
try {
ctor = Lookup.class.getDeclaredConstructor(Class.class);
ReflectionUtils.makeAccessible(ctor);
}
catch (Exception ex) {
// this is the signal that we are on Java 9 (encapsulated) and can't use the accessible constructor
// approach.
if (!ex.getClass().getName().equals("java.lang.reflect.InaccessibleObjectException")) {
throw new IllegalStateException(ex);
}
}
this.constructor = ctor;
}
private volatile boolean constructorResolved;

private Constructor<Lookup> constructor;

private final Supplier<Constructor<Lookup>> constructorSupplier =
() -> {
if (!this.constructorResolved) {
Constructor<Lookup> ctor = null;
try {
ctor = Lookup.class.getDeclaredConstructor(Class.class);
ReflectionUtils.makeAccessible(ctor);
}
catch (Exception ex) {
// this is the signal that we are on Java 9 (encapsulated) and can't use the accessible
// constructor approach.
if (!ex.getClass().getName().equals("java.lang.reflect.InaccessibleObjectException")) {
throw new IllegalStateException(ex);
}
}
this.constructor = ctor;
this.constructorResolved = true;
}
return this.constructor;
};

@Override
MethodHandle lookup(Method method) throws ReflectiveOperationException {
if (this.constructor != null) {
return this.constructor.newInstance(method.getDeclaringClass())
Constructor<Lookup> lookupConstructor = this.constructorSupplier.get();
if (lookupConstructor != null) {
return lookupConstructor.newInstance(method.getDeclaringClass())
.unreflectSpecial(method, method.getDeclaringClass());
}
else {
Expand All @@ -151,7 +159,7 @@ MethodHandle lookup(Method method) throws ReflectiveOperationException {

@Override
boolean isAvailable() {
return this.constructor != null;
return this.constructorSupplier.get() != null;
}

},
Expand All @@ -160,7 +168,6 @@ boolean isAvailable() {
* Fallback {@link MethodHandle} lookup using {@link MethodHandles#lookup() public lookup}.
*/
FALLBACK {

@Override
MethodHandle lookup(Method method) throws ReflectiveOperationException {
return doLookup(method, MethodHandles.lookup());
Expand Down Expand Up @@ -191,7 +198,7 @@ private static MethodHandle doLookup(Method method, Lookup lookup) throws Reflec
* @return the {@link MethodHandleLookup}
* @throws IllegalStateException if no {@link MethodHandleLookup} is available.
*/
public static MethodHandleLookup getMethodHandleLookup() {
static MethodHandleLookup getMethodHandleLookup() {
for (MethodHandleLookup it : MethodHandleLookup.values()) {
if (it.isAvailable()) {
return it;
Expand Down