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[jOOQ/jOOQ#11684] Cannot use ConcurrentHashMap.computeIfAbsent()

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Because that would prevent calling it recursively due to an implementation flaw in the JDK method.
This commit is contained in:
Lukas Eder 2021-03-21 19:31:25 +01:00
parent 32b2170830
commit dda4215190
1 changed files with 14 additions and 2 deletions
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16
jOOQ/src/main/java/org/jooq/impl/Tools.java
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@ -3354,8 +3354,20 @@ final class Tools {
if (cacheOrNull == NULL)
return operation.get();
// The cache is guaranteed to be thread safe by the CacheProvider contract
Object result = ((Map<Object, Object>) cacheOrNull).computeIfAbsent(key.get(), k -> defaultIfNull(operation.get(), NULL));
// The cache is guaranteed to be thread safe by the CacheProvider
// contract. However since we cannot use ConcurrentHashMap.computeIfAbsent()
// recursively, we have to revert to double checked locking nonetheless.
Map<Object, Object> cache = (Map<Object, Object>) cacheOrNull;
Object result = cache.get(key);
if (result == null) {
synchronized (cache) {
result = cache.get(key);
if (result == null)
cache.put(key, (result = operation.get()) == null ? NULL : result);
}
}
return (V) (result == NULL ? null : result);
}