Unnecessary string in a method (overload methods)

Question

How do I make a method that does not require an objects, but if there is one it would use it!

Like this

void cls(String source){
        if(source.isEmpty()){
            source = "Unknown source";
        }
        output.setText("Screen cleared from " + source);
    }

And later when I call this I could do

cls();

but it throws an error because it needs a string

cls("string");

but I want for both to work!

Note, you may want to give your method distinct meaningful names rather than overloading. — Tom Hawtin - tackline, Jul 10 '13 at 14:41
@TomHawtin-tackline not neccesarily, it looks like common cls command to clear a screen (also noted in the output.setText("___") message). — Luiggi Mendoza, Jul 10 '13 at 14:42
To last editor: adding *How to overload* in title would make the question to be closed. In its current state, it shows lack of knowledge from OP about how to accomplish this task. — Luiggi Mendoza, Jul 10 '13 at 14:45
[This question](http://stackoverflow.com/questions/965690/java-optional-parameters) is related and might help OP understand Java's limitations as far as optional arguments within a single method definition. — ajp15243, Jul 10 '13 at 14:50

score 7 · Accepted Answer · edited Jul 10 '13 at 14:42

7

You use two methods with the same name but different signatures (that's called overloading):

void cls() {
    // ???
}

void cls(String source){
    if(source.isEmpty()){
        source = "Unknown source";
    }
    output.setText("Screen cleared from " + source);
}

or varargs:

void cls(String... sources){
    if (sources.length > 0) {
        // ???
    }
}

edited Jul 10 '13 at 14:42

ajp15243

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answered Jul 10 '13 at 14:37

Matt Ball

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This works, but what if I have void `cls(String source, boolean isAllowed){}` – donemanuel Jul 10 '13 at 14:42
I want both string source and boolean isAllowed to be unnecessary! – donemanuel Jul 10 '13 at 14:43
4

@donemanuel You can "chain" overloaded methods together for as many arguments as you want. Just have your no-args method call the full version, with default arguments. `void cls() { cls("Unknown source", false); }` or whatever else you want for your default arguments. – Henry Keiter Jul 10 '13 at 14:44

score 0 · Answer 2 · answered Jul 10 '13 at 14:39

0

you can create two methods. something like this:

void cls(String source) {...}

void cls() {
    return cls("Unknown source");
}

now you can call cls with or without the String parameter

answered Jul 10 '13 at 14:39

Vegard

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Unnecessary string in a method (overload methods)

2 Answers2