StringBuilder append content to a new line every time

Question

I am building a validation routine that validates contents and then gives warning (for failures) in form of StringBuilder. Say in below code I am checking lower bound for values paramX and paramY.

 StringBuilder sb= new StringBuilder();

        if(paramX<10){
            sb.append("paramX cannot be less than 10 ");
        }

        if(paramY<20){
            sb.append("paramY cannot be less than 20 ");
        }

        System.out.println(sb);

It gives output as: paramX cannot be less than 10 paramY cannot be less than 20

but i want output such that, each appended String will be printed on new line. Like below.

paramX cannot be less than 10 

paramY cannot be less than 20

I used following workarounds, but ended up repeating same code again and again(Which i don't want to).

sb.append(System.getProperty("line.separator")); // Add Explicit line separator each time
sb.append("\n");
sb.append("paramX cannot be less than 10 \n");

Is there a simpler way to do it?

Answer 1

If you don't want to do it over and over then write a helper method:

public void appendString(StringBuilder builder, String value) {
    builder.append(value + System.lineSeparator());
}

Then call:

if(paramX<10){
    appendString(sb, "paramX cannot be less than 10 ");
}

This way you only have a single place to maintain if you need to change the output format for the errors.