What's the use of storm's MemoryMapState?
This article mainly introduces "what is the use of storm's MemoryMapState". In daily operation, I believe many people have doubts about the use of storm's MemoryMapState. The editor consulted all kinds of materials and sorted out simple and easy-to-use methods of operation. I hope it will be helpful to answer the questions of "what is the use of storm's MemoryMapState?" Next, please follow the editor to study!
MemoryMapState is a kind of state defined in trident, which is used to save the data calculated by storm trident.
Take a look at the relationship between MemoryMapState and State
MemoryMapState stores all data in internal static properties
Static ConcurrentHashMap _ dbs = new ConcurrentHashMap ()
About ConcurrentHashMap, it can be used as a thread-safe map
Public class ConcurrentHashMap extends AbstractMap implements ConcurrentMap, Serializable
The operation of ConcurrentHashMap by MemoryMapState mainly depends on the inner class MemoryMapStateBacking.
Static class MemoryMapStateBacking implements IBackingMap, ITupleCollection
Storm has learned that it is full of condoms, and the method of a class is actually a method that calls one of its own attributes, many layers.
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