append
Description: The append function
returns the result of appending the argument to the value of the Subject. If the Subject is
null, returns the argument itself.
Subject Type: String
Arguments:
value : The String to append to the end of the Subject
Return Type: String
Examples: If the "filename" attribute has the
value "a brand new filename.txt", then the Expression
${filename:append('.gz')} will return "a brand new
filename.txt.gz".