74th: Thinking about pattern matching in Scala from the perspective of Spark source

Today, Mr. Wang studied the function of pattern matching in Scala from the source point of view. Let's look at this pattern match in the source code:

From the code we can see that case Registerworker (Id,workerhost,........) {} Here is a pattern match, and our pattern-matching class registerworker before it is defined, such as:

We can see that our pattern matching class is already defined, and when our master receives a message from the worker, it makes a pattern match:

。

There is also a knowledge point where we can find that when we do pattern matching, we do not use the new method to create a new instance, but instead use the Registerworker (ID,.....) directly. And here, we are using the associated application method of the class. When a pattern match is made, the Unapply method is used to parse the content that the instance passes over.

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74th: Thinking about pattern matching in Scala from the perspective of Spark source