Package org.apache.hadoop.hbase.util
Class ConcurrentMapUtils
java.lang.Object
org.apache.hadoop.hbase.util.ConcurrentMapUtils
Utility methods for dealing with Collections, including treating null collections as empty.
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Constructor Summary
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Method Summary
Modifier and TypeMethodDescriptionstatic <K,
V> V computeIfAbsent
(ConcurrentMap<K, V> map, K key, Supplier<V> supplier) In HBASE-16648 we found that ConcurrentHashMap.get is much faster than computeIfAbsent if the value already exists.static <K,
V> V computeIfAbsent
(ConcurrentMap<K, V> map, K key, Supplier<V> supplier, Runnable actionIfAbsent) static <K,
V> V computeIfAbsentEx
(ConcurrentMap<K, V> map, K key, IOExceptionSupplier<V> supplier) In HBASE-16648 we found that ConcurrentHashMap.get is much faster than computeIfAbsent if the value already exists.
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Constructor Details
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ConcurrentMapUtils
public ConcurrentMapUtils()
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Method Details
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computeIfAbsent
In HBASE-16648 we found that ConcurrentHashMap.get is much faster than computeIfAbsent if the value already exists. Notice that the implementation does not guarantee that the supplier will only be executed once. -
computeIfAbsentEx
public static <K,V> V computeIfAbsentEx(ConcurrentMap<K, V> map, K key, IOExceptionSupplier<V> supplier) throws IOExceptionIn HBASE-16648 we found that ConcurrentHashMap.get is much faster than computeIfAbsent if the value already exists. So here we copy the implementation ofConcurrentMap.computeIfAbsent(Object, java.util.function.Function)
. It uses get and putIfAbsent to implement computeIfAbsent. And notice that the implementation does not guarantee that the supplier will only be executed once.- Throws:
IOException
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computeIfAbsent
public static <K,V> V computeIfAbsent(ConcurrentMap<K, V> map, K key, Supplier<V> supplier, Runnable actionIfAbsent)
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