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Add fast-path in BeanUtils#instantiateClass 

For no-args constructor.

See gh-24104
This commit is contained in:
stsypanov 2019-11-27 14:45:16 +02:00 committed by Sébastien Deleuze
parent 42ab1b75e7
commit edcc559b4a
1 changed files with 27 additions and 1 deletions
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28
spring-beans/src/main/java/org/springframework/beans/BeanUtils.java
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@ -51,6 +51,7 @@ import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.CollectionUtils;
import org.springframework.util.ConcurrentReferenceHashMap;
import org.springframework.util.ObjectUtils;
import org.springframework.util.ReflectionUtils;
import org.springframework.util.StringUtils;
@ -188,11 +189,18 @@ public abstract class BeanUtils {
try {
ReflectionUtils.makeAccessible(ctor);
if (KotlinDetector.isKotlinReflectPresent() && KotlinDetector.isKotlinType(ctor.getDeclaringClass())) {
if (ObjectUtils.isEmpty(args)) {
return KotlinDelegate.instantiateClass(ctor);
}
return KotlinDelegate.instantiateClass(ctor, args);
}
else {
int parameterCount = ctor.getParameterCount();
Assert.isTrue(args.length <= parameterCount, "Can't specify more arguments than constructor parameters");
if (parameterCount == 0) {
return ctor.newInstance();
}
Class<?>[] parameterTypes = ctor.getParameterTypes();
Assert.isTrue(args.length <= parameterTypes.length, "Can't specify more arguments than constructor parameters");
Object[] argsWithDefaultValues = new Object[args.length];
for (int i = 0 ; i < args.length; i++) {
if (args[i] == null) {
@ -887,6 +895,24 @@ public abstract class BeanUtils {
return kotlinConstructor.callBy(argParameters);
}
/**
* Instantiate a Kotlin class using provided no-arg constructor.
* @param ctor the constructor of the Kotlin class to instantiate
*/
public static <T> T instantiateClass(Constructor<T> ctor)
throws IllegalAccessException, InvocationTargetException, InstantiationException {
KFunction<T> kotlinConstructor = ReflectJvmMapping.getKotlinFunction(ctor);
if (kotlinConstructor == null) {
return ctor.newInstance();
}
List<KParameter> parameters = kotlinConstructor.getParameters();
Assert.isTrue(parameters.isEmpty(), "Default no-args constructor must have no params");
Map<KParameter, Object> argParameters = Collections.emptyMap();
return kotlinConstructor.callBy(argParameters);
}
}
}