赋值的左侧必须是变量是否有必要？

Question

public String toString() {    
    return " Recipient:"+  this.toString(this.getRecipient()) +
               " CC:"+ this.toString
                           (
                       if(this.getCC()==null)
                       {
                           getCC() = "";
                       }
                           ) +
               " Subject:"+this.getSubject() +
               " Body:"+ this.getBody() +
               " files:"+ this.getFiles();        
}

I am having this error in:

getCC() = ""; <--------- Here.

Do you know why is this happening? Thanks in advance

Answer 1

You can't assign a value to the return of a method. You also can't place an expression inside a method which takes no arguments. What you appear to have intended was to use a variable.

String cc = getCC();
if (cc == null) cc = "";
return ... " CC:" + cc + ...