检查Java中2种方法的特定结果的最佳方法

Question

I have the following method

public Message JavaMethod(String id1, String id2)

In which I need to call a Dao class's method to verify that an user with the provided Id exist, and if it does not, create a message detailing the Id that couldn't be found on the database with the following method:

createMessage("Message string",Enum.TYPE,IdofMissingUser);

At first I thought of doing it like this:

public Message JavaMethod(String id1, String id2) {

        if(Dao.findUser(id1) == null || Dao.findUser(id2) == null){
           return createMessage("Error",Enum.Error,id1);
        }else{
           //do some other stuff
        }
}

But obviously this way I won't know which of the ids has not been found.

So I went ahead and created an ugly if else cycle:

public Message JavaMethod(String id1, String id2) {

    if (Dao.findUser(id1) == null) {
        return createMessage("Error", Enum.Error, id1);

    } else if (Dao.findUser(id2) == null) {
        return createMessage("Error", Enum.Error, id2);
    } else {
        // Do stuff after veryfing users exists
        return createMessage("All OK", Enum.OK, messageData);
    }
}

But I'm not feeling really confident that this is the best solution for this basic issue.

What would you guys recommend in this case?

Answer 1

You could wrap the ids in a list and use a for loop:

public Message someMethod(String id1, String id2) {
    for (String id: Arrays.asList(id1, id2)) {
        if (Dao.findUser(id) == null) {
            return createMessage("Error", Enum.Error, id);
        }
    }
    // Do stuff after verifying users exists
    return createMessage("All OK", Enum.OK, messageData);
}

Answer 2

If you're only ever going to have two IDs, you could deal with a shorthand boolean. Question is whether that makes it less readable though. Eg

public Message JavaMethod(String id1, String id2) {
        User user1 = Dao.findUser(id1);
        User user2 = Dao.findUser(id2);            
        if(user1  == null || user2  == null){
           return createMessage("Error",Enum.Error,user1 == null ? id1 : id2);
        }else{
           //do some other stuff
        }
}

This also doesn't deal with if both of the IDs were null, for that you could extend it:

public Message JavaMethod(String id1, String id2) {
        User user1 = Dao.findUser(id1);
        User user2 = Dao.findUser(id2); 
        if(user1  == null || user2  == null){
           return createMessage("Error",Enum.Error,user1  == null && user2  == null? both : user1 == null ? id1 : id2);
        }else{
           //do some other stuff
        }
}

You'd need to define what you would return for the both variable

More details on the shorthand boolean annotation can be found here