Regex - determine matrix from String

how can I create simple matrix for String that could be contains following combinations

123456 ABC    
123456AB1
123456AB12
123456AB123
123456

for example

if ("\\d + \\d + \\d + \\d + \\d + \\d  
   + \\s 
   + [a-zA-Z]+[a-zA-Z]+[a-zA-Z]") {
   //passed variant from input in form 123456 ABC

} else if ("\\d + \\d + \\d + \\d + \\d + \\d 
   + [a-zA-Z]+[a-zA-Z]+[a-zA-Z]
   + \\d") {
   //passed variant from input in form 123456AB1

} else if ("\\d + \\d + \\d + \\d + \\d + \\d 
   + [a-zA-Z]+[a-zA-Z]+[a-zA-Z]
   + \\d + \\d") {
   //passed variant from input in form 123456AB12

} else if ("\\d + \\d + \\d + \\d + \\d + \\d 
   + [a-zA-Z]+[a-zA-Z]+[a-zA-Z]
   + \\d + \\d + \\d") {
   //passed variant fro开发者_如何学编程m input in form 123456AB123

} else if ("\\d + \\d + \\d + \\d + \\d + \\d") {
   //passed variant from input in form 0123456

} else {
   //doesn't match
}

You could for instance use the following regexs

123456 ABC  -> \\d{6}\\s\\w{3}
123456AB1   -> \\d{6}\\w{3}
123456AB12  -> \\d{6}\\w{4}
123456AB123 -> \\d{6}\\w{5}
123456      -> \\d{6}

The if-clauses can be used as in your example, e.g.,

if(str.matches("\\d{6}\\s\\w+") { 
    ... 
} ...

Just as your question, these regex variants only covers the exact combinations from this example.

If you need to split the input strings into the relevannt parts, try this regex: (\d{6})\s*([a-zA-Z]*)(\d*)

For 123456AB123 group 1 would be 123456, group 2 would be AB and group 3 would be 123. When groups are missing they'd just be an emtpy string.

Note that if the only difference between the variants would be the groups (group 1 always exists, groups 2 and 3 might be empty) then the if-else on different regexes would not be necessary. Instead you might have something like this (pseudocode):

if(matches) {
  groups[3] = extractGroups();

  //groups[0] should always exist

  if(groups[1] is not empty) {
    ...
  }

  if(groups[2] is not empty) {
    ...
  }
} else {
  handle non-match
}