Java to xslt conversion

I have below java code. I need to convert to xslt. How do i achieve this?
Requirement: 
If (first name + last name) exceeds 50 char, then use (first char of first name + complete last name) and create ErrorMessage indicating that name got truncated.


String strFirstName = "";
String strLastName = "";
StringBuffer ErrorMessage = new StringBuffer("");

StringBuffer name = new StringBuffer(strFirstName);
name.append(" " + strLastName);

if(name.length() > NAME_LEN){

//Build the name
name.delete(0, name.length());
name.append(strFirstName.substring(0,1) + " " + strLastName.substring(0));

//Name = name.substring(0,NAME_LEN);
if(name.length() > NAME_LEN)
    Name = name.substring(0,NAME_LEN);   
else 
    Name = name.substring(0,name.length());

ErrorMessage = ErrorMessage.append("Name= " + strFirstName + " " + strLastName + ",");
} else{
Name = name.toString();
}