Select a regular expression syntax in the topmost choice menu.
    Type a regular expression in the first text field.  Then in
    the Search Input text area, enter text that you want to
    search.  Click the Search button to search the input text.
    The results will appear in the Search Results text area.
    The Reset button will clear the regular expression, input,
    and result text.
    
                                                
    There are two choice menus that affect the regular expression
    search.  The contains() item causes the
    contains() method of the PatternMatcher interface to be
    used to perform the search.  This search is done in a while loop,
    finding all pattern matches occuring within the input.  The
    matches() item causes the matches() method of
    the PatternMatcher interface to be used to perform the search.  The
    matches() method only tests if all the input
    EXACTLY matches the regular expression.  It does not check
    to see if there is a match somewhere inside the input. That is
    what the contains() method is for.  This is sometimes
    a point of confusion for users who have tried other packages.  In
    Jakarta ORO, matches() is used to find exact matches,
    and contains is used to find a match contained in the
    input.
    
                                                
    The Case Sensitive and Case Insensitive choice items
    are self-explanatory.  Case Sensitive causes the regular
    expression to be compiled with case sensitivity enabled. Case
    Insensitive causes the regular expression to treat upper and
    lower case characters the same.
    
                                                
    The Search Results text area will display all the matches
    found in the input when the contains() choice item is
    selected.  It will also display what the parenthesized subgroups
    of a regular expression matched.  When the matches() choice
    item is selected, only whether or not the input exactly matched
    the pattern is indicated.
    
                                                
    Please note that if you don't enter anything for a regular
    expression, it will be compiled as an expression matching a
    zero-length string (the null string), which will match before and
    after every character in the input.