本文介绍了理解“TypeElement'和'的declaredType”在Java接口的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

这两个接口的一个用途,就是写注释处理器。

One usage of these two interface, is to write annotation processor.

作为Java初学者,我发现,是由这两个包加间接的水平:
javax.lang.model.element中的&安培; javax.lang.model.type中来提供关于Java 接口和java 混乱。

As a java beginner, I find the level of indirection that is added by these two packages:javax.lang.model.element & javax.lang.model.type to provide metadata about java interface and java class confusing.


.........

.........

Java的文档注释说,

java doc comments say,

TypeElement 重新presents一个接口程序元素。提供对有关类型及其成员的信息。请注意,枚举
  类型是一种类和注释类型是一种接口

的declaredType 重新presents一个声明类型,是一个键入或接口类型。这包括参数化类型,如 java.util.Set中的<弦乐方式> 以及原始类型

DeclaredType represents a declared type, either a class type or an interface type. This includes parameterized types such as java.util.Set<String> as well as raw types.

两者之间的区别:

而在 TypeElement 重新presents一个接口元素的一个的declaredType 重新presents一个接口键入的,后者是使用(或调用的)前的。

我如何区分行话的元素的距离的键入的?例如:如何为元素的从类不同键入?请帮我用一个例子。

How do I differentiate the jargon element from type? For example: How is class element different from class type? Please help me with an example.

推荐答案

元素的是,你用它来组成一个软件部分,即 ExecutableElement ■哪些,顾名思义,包含可执行code,它描述了一种存储 VariableElement TypeElement ■哪些合计持有这些。这是Java编程语言的一个特殊属性(如面向对象的语言),有没有顶级的功能,也没有全局变量没有 TypeElement ,它们被定义的。

The elements are the parts that you use to compose a software, i.e. ExecutableElements which, as the name suggests, contain executable code, VariableElements which describe a kind of storage and TypeElements which hold these together. It’s a special property of the Java programming language (as an object oriented language) that there are no top-level functions nor global variables without a TypeElement, in which they are defined.

在换句话说,如果你写一个Java程序,你将永远有含有至少一种类型声明至少有一个的.java 源文件。这 TypeElement 将有可能至少包含一个 ExecutableElement 来弥补一个有用的软件。在 TypeElement 可以包含多个 ExecutableElement S, VariableElement 和嵌套 TypeElement 秒。这是你的程序的结构

In other words, if you write a Java program, you will always have at least one .java source file containing at least one type declaration. That TypeElement will likely contain at least one ExecutableElement to make up a useful software. The TypeElement may contain multiple ExecutableElements, VariableElements and nested TypeElements. That’s the structure of your program.

A 键入的是,只要你声明成员或局部变量,你使用的东西,同时也宣告一个超类或-interface时。但是,让我们关注的变量,以更好地理解:

A type is something which you use whenever you declare a member or local variable, but also when declaring a super class or -interface. But let’s focus on variables, for a better understanding:

一个变量可以有一个原语类型,这是固有的编程语言,它也可以有一个类型,其存在是隐含的,例如当有键入 X ,你也可以使用数组类型 X [] 在一个变量声明,但只在声明类型的是必须有相应的 TypeElement ,再presenting的东西,开发商写(或已生成的类型一个工具)。泛型还允许您撰写的类型,例如声明类型的变量设置 - LT ;?扩展号码&GT; ,而设置编号声明类型的已相应的程序元素...

A variable can have a primitive type, which is intrinsic to the programming language, it can also have a type whose existence is implied, e.g. when there is a type X, you can also use the array type X[] in a variable declaration, but only the declared type is a type which must have a corresponding TypeElement, representing something, a developer has written (or has been generated by a tool). Generics also allow you to compose types, e.g. declare a variable of type Set<? extends Number> whereas Set and Number are declared types which have corresponding program elements…

这篇关于理解“TypeElement'和'的declaredType”在Java接口的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!

08-06 14:07