Join strings with a separator and stripping empty ones

Question

I need the code logic for the following:

These are the three String variables,

String s1 = "A"; String s2 = "B"; String s3 = "C";

I need to have the following outputs based on the given scenarios:

• Scenario #1 Actual output should be "A / B / C"
• Scenario #2 When s1 is empty, output should be "B / C"
• Scenario #3 When s2 is empty, output should be "A / C"
• Scenario #4 When s3 is empty, output should be "A / B"`

Is this possible using ternary operation?

Answer 1

You can do it with with the help of Guava class Joiner and Apache Commons Lang StringUtils.defaultIfBlank:

Joiner.on("/").skipNulls().join(
  defaultIfBlank(s1, null),
  defaultIfBlank(s2, null),
  defaultIfBlank(s3, null)
);

You can extract the three lines of "defaultIfBlank" into a method with a loop if you need to process an arbitrary number of strings.

Answer 2

A java8-way with a stream

Arrays.stream(new String[]{null, "", "word1", "", "word2", null, "word3", "", null})
    .filter(x -> x != null && x.length() > 0)
    .collect(Collectors.joining(" - "));

Answer 3

You can do:

result = ((s1==null)?"":(s1+"/"))+((s2==null)?"":(s2+"/"))+((s3==null)?"":s3);

See it