Surround With

In order to support the Code | Surround With... action, the plugin needs to register one or more implementations of the SurroundDescriptor interface in the com.intellij.lang.surroundDescriptor extension point. Each of the surround descriptors defines a possible type of code fragment which can be surrounded - for example, one surround descriptor can handle surrounding expressions, and another can handle statements. Each surround descriptor, in turn, contains an array of Surrounder objects, defining specific templates which can be used for surrounding the selected code fragment (for example, Surround With if, Surround With for and so on).

当调用Surround With ...动作时,IDE将查询该语言的所有环绕描述符,直到它找到一个从其getElementsToSurround()方法返回非空数组的描述符.

然后它调用

Surrounder.isApplicable()<! - ＃L46–>

该描述符中每个surrounder的方法,用于检查特定模板是否适用于当前上下文.

一旦用户从弹出菜单中选择了特定的surrounder,就可以了

Surrounder.surroundElements()<! - ＃L57–>

方法用于执行环绕动作.