public static final class LambdaTypeRecognizer.Java8Makeshift extends Object implements LambdaTypeRecognizer
The condition to recognize a lambda type is:
- Class.isSynthetic() must return true.
- The String returned by Class.getName() must contain the value "$$Lambda$".
This approach works correctly to recognize lambda types in Java 8. However,
it comes with the following two risks:
1.) Should any synthetic but non-lambda class contain that String in its type name,
it will falsely be identified as a lambda.
2.) Should the JDK-internal implementation detail lambda type String that the used String refers to ever
change in a future release, this approach will no longer recognize lambda types.
Unfortunately, there is no more reliable way known to the author of this class, despite intensive research.
The underlying problem is that the Java type system (at least in version 8) does not provide a proper way
of querying if a type is a lambda type. Brian Goetz wrote on Stackoverflow that if one needs to make such a
distinction, one surely made a mistake. However, there is a very simple example that objectively proves him
wrong:
In contrast to other generated classes like anonynmous inner classes, the Java type system cannot resolve the
type String for a lambda type that it itself created. This sets lambda types apart from other types in certain
situations involving generic handling of types, thus creating an absolutely essential need to indeed recognize
lambda types.
Maybe someone can explain this trait of Java's lambda concept to its creator, so he can understand and remedy
the error he made.
To indicate the weakness of the current approach, its implementation is explicitely named
LambdaTypeRecognizer.Java8Makeshift.
Hopefully, there will be a better, proper way in the future, causing a second implementation
("JavaXX") to be created.
LambdaTypeRecognizer.Java8Makeshift| Modifier and Type | Method and Description |
|---|---|
boolean |
isLambdaType(Class<?> type) |
static String |
lambdaTypeNameSearchSubject() |
static boolean |
staticIsLambdaType(Class<?> type) |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitJava8Makeshift, Newpublic static String lambdaTypeNameSearchSubject()
public static boolean staticIsLambdaType(Class<?> type)
public final boolean isLambdaType(Class<?> type)
isLambdaType in interface LambdaTypeRecognizerCopyright © 2022 MicroStream Software. All rights reserved.