title: Regex match on specific pattern
body: <p>Definitely not an expert at Regex so I'm struggling here a bit. I'd like to create a pattern that will match the following format:</p>
  
  <pre><code>cat:hairy, rat:hairless               [correct]
  
  cat:hairy, rat:hairless, dog:fat      [correct]
  
  cat:hairy,      rat:hairless          [correct]
  
  
  
  cat                                   [incorrect]
  
  cat, dog                              [incorrect]
  
  cat:hairy,                            [incorrect]
  
  cat:hairy, monkey, dog:fat            [incorrect]
  
  cat:hairy rat:hairless, dog:fat       [incorrect]
  </code></pre>
  
  <p>So far the regex I have is as follows:</p>
  
  <pre><code>((\S):(\S))
  </code></pre>
  
  <p>However, this does not work in all cases. Any help would be appreciated!</p>
  
  <p><strong>Update</strong>
  <em>Language</em>: Java
  <em>Format</em>: the xxx:yyy can be any letter or number, upper or lower case</p>