In -depth understanding of "AutoValue Processor" framework technical principles in the Java class library

AutoValue Processor is a Java class library based on the annotation processor that is used to automatically create Java classes that automatically create non -variable types.It is developed by Google and can be used with the AutoValue class library. By reducing the model code and providing a more concise and secure way, the Java class is defined. The principle of AutoValue Processor is to read the annotation information in the source code during compilation through the annotation processor, and generate the corresponding Java code according to the annotation information.It realizes a variable value type by generating static final fields, constructors (), Hashcode (), Tostring () related to this value type, and achieve an irresistible value type. It is very simple to use AutoValue Processor.First, the autoValue annotation needs to be used for annotations in the value type of value.Next, when compiling, AutoValue Processor will automatically read this annotation and generate a corresponding value type Java class based on the information of the annotation. Below is a simple example, showing how to use AutoValue Processor to create an immutable Person class: // Use the autoValue annotation marker Person class @AutoValue public abstract class Person { public abstract String getName(); public abstract int getAge(); // Create () generated by autoValue Processor public static Person create(String name, int age) { return new AutoValue_Person(name, age); } } In the above example, we use AutoValue annotations to mark the Person class.AutoValue Processor reads this annotation and generates a Java class called AutoValue_person based on the information information. The generated AutoValue_person class is shown below: // Auto -generate autoValue_person class final class AutoValue_Person extends Person { private final String name; private final int age; AutoValue_Person(String name, int age) { if (name == null) { throw new NullPointerException("Null name"); } this.name = name; this.age = age; } public String getName() { return name; } public int getAge() { return age; } // Automatically generate Equals () Method public boolean equals(Object o) { ... } // Automatically generate the HashCode () method public int hashCode() { ... } // Automatically generate tostring () method public String toString() { ... } } The generated AutoValue_person class contains the two fields of name and Age, and provides the corresponding Getter method.It also implements methods such as Equals (), HashCode (), and Tostring (), so that this type has non -degeneration and reasonable default behavior. By using AutoValue Processor, we can simplify the creation process of unable variable type types to avoid writing a large number of model code manually.At the same time, it also provides the default implementation of type security, which can improve development efficiency while ensuring the correctness of the program. In summary, AutoValue Processor is a powerful tool that can automatically generate unable variable types of Java classes, providing a more concise and secure way to define the Java class.By using AutoValue Processor, we can reduce redundant code and make the code more easy to read and maintain.