Scala introduction

Object-oriented characteristic

Scala is a pure object-oriented language, and every value is an object. The data types and behaviors of objects are described by classes and attributes.

There are two ways to extend the class abstraction mechanism: one is subclass inheritance, and the other is flexible blending mechanism. These two approaches can avoid the problems of multiple inheritance.

Functional programming

Scala is also a functional language, and its functions can be used as values. Scala provides lightweight syntax for defining anonymous functions, supports higher-order functions, allows nesting of multi-tier functions, andsupports Corialization. Case of Scala class and its built-in pattern matching are equivalent to the algebraic types commonly used in functional programming languages.

Further, programmers can use Scala’s pattern matching to write regular expression-like code to process XML data.

Static type

Scala has a type system that ensures code security and consistency through compile-time checking. The type system specifically supports the following features:

• Generic class

• Covariant and inverter

• Dimensioning

• Upper and lower bound constraints of type parameters

• Treat classes and abstract types as object members

• Compound type

• Explicitly specify the type when referencing yourself

• View

• Polymorphic method

Expansibility

Scala is designed based on the fact that in practice, domain-specific application development often requires domain-specific language extensions. Scala provides many unique language mechanisms to easily and seamlessly add new language structures in the form of libraries:

• Any method can be used as a prefix or suffix operator

• Closures can be constructed automatically based on the expected type.

Concurrency

Scala uses Actor as its concurrency model, and Actor is a threaded entity that sends and receives messages through mailboxes. Actor can reuse threads,so you can use millions of Actor in your program, while threads can only create a few thousand. In versions later than 2.10, Akka was used as its default Actor implementation.