"Spark Asia-Pacific Research series" Spark Combat Master Road-2nd Chapter hands-on Scala 2nd bar (3)

5. Apply method and Singleton object in Scala  

to create a new class:

As an additional point, the methods placed in object objects are static methods, as follows:

Next look at the use of the Apply method:

The above code always when we use "val a = Applytest ()" will cause the call of the Apply method and return the value of the method call, that is, the instantiated object of the applytest.

C The lass can also be used by the Apply method, as shown in the following ways:

Because the methods and properties in object are static, this is the ideal vector for singleton objects, as shown in the example code:

In other words, object itself is a singleton!

"Spark Asia-Pacific Research series" Spark Combat Master Road-2nd Chapter hands-on Scala 2nd bar (3)