Java 类设计 - 太多的 if 条件

Question

我的代码片段如下:

public void execute(Parameters params) {
    Long requestType = params.getRequestType();
    // Based on the requestType the name of the project would be different
    getName(requestType); 
    // Same as above
    getDescription(requestType) 
    // Project here is a collection of different requests
    Long projectId = createProject(name, description) 
    RequestContents requestContents = params.getRequestContents();
    for(RequestContent requestcontent : requestcontents) {
        Long requestId = createRequest(name, description, projectId);
        updateRequest(requestId, requestContent1);
    }
    // Based on the  requestType, mail content would differ 
    String mailContent = getMailContent(requestType, projectId) 
    sendMail(mailContent); 
}

函数 sendMail、createProject、createRequest 的输出取决于 requestType，因此这些函数将最终有多个 if-else 条件。为此类建模以避免这种情况的正确方法是什么？

Answer 1

一种方法是创建一个抽象类 AbstractRequest 具有抽象方法 sendMail、createProject 等，然后有几个具体的子类 RequestType1 RequestType2 等每个都有不同的 sendMail 等实现。我猜他们称之为策略模式。