Java - Check Not Null/Empty else assign default value

Question

I am trying to simplify the following code.

The basic steps that the code should carry out are as follows:

1. Assign String a default value
2. Run a method
3. If the method returns a null/empty string leave the String as default
4. If the method returns a valid string set the String to this result

A Simple example would be:

    String temp = System.getProperty("XYZ");
    String result = "default";
    if(temp != null && !temp.isEmpty()){
        result = temp;
    }

I have made another attemp using a ternary operator:

    String temp;
    String result = isNotNullOrEmpty(temp = System.getProperty("XYZ")) ? temp : "default";

The isNotNullOrEmpty() Method

 private static boolean isNotNullOrEmpty(String str){
    return (str != null && !str.isEmpty());
}

Is it possible to do all of this in-line? I know I could do something like this:

String result = isNotNullOrEmpty(System.getProperty("XYZ")) ? System.getProperty("XYZ") : "default";

But I am calling the same method twice. I would be something like to do something like this (which doesn't work):

String result = isNotNullOrEmpty(String temp = System.getProperty("XYZ")) ? temp : "default";

I would like to initialize the 'temp' String within the same line. Is this possible? Or what should I be doing?

Thank you for your suggestions.

Tim

Answer 1

Use Java 8 Optional (no filter needed):

public static String orElse(String defaultValue) {
  return Optional.ofNullable(System.getProperty("property")).orElse(defaultValue);
}