http://www.javatpoint.com/java-oops-concepts
Rules for Constructor
rule for static
Usage of this()
Rules for Constructor
rule for static
Usage of this()
http://www.vogella.com/tutorials/JavaRegularExpressions/article.html Generic Java function to match RE public static boolean testRE (String s){ Pattern pattern = Pattern.compile("\\d{3}"); Matcher matcher = pattern.matcher(s); if (matcher.find()){ return true; } return false; [tT]rue - match true or true [tT]rue|[yY]es - matches true,True,yes,Yes *true.* - matches exactly true [a-zA-Z]{3} - match 4 character word ^[^\\d] - true if String dosent match a digit at beggining ([\\w&&[^b]])* - true if string contains characters excluding b "[^0-9]*[12]?[0-9]{1,2}[^0-9]*" - less than 300 (HOW????) .*(jim|joe).* - Match either jim or Joe A phone number in this example consists either out of 7 numbers in a row or out of 3 number, a (white)space or a dash and then 4 numbers. \\d\\d\\d([,\\s])?\\d\\d\\d\\d - 1233323322 [0-9]{2} (Check Correctness) -check if a text contains a number with 3 digits. \\d{3} \b(\w+)\s+\1\b - find duplicated words following regular expression allows you to find the "title" word, in case it starts in a new line, potentially with leading spaces. (\n\s*)title Password compexity : ((?=.*\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%]).{6,20}) ( # Start of group (?=.*\d) # must contains one digit from 0-9 (?=.*[a-z]) # must contains one lowercase characters (?=.*[A-Z]) # must contains one uppercase characters (?=.*[@#$%]) # must contains one special symbols in the list "@#$%" . # match anything with previous condition checking {6,20} # length at least 6 characters and maximum of 20 ) # End of group ^[_A-Za-z0-9-]+(\\.[_A-Za-z0-9-]+)*@[A-Za-z0-9]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$ #start of the line [_A-Za-z0-9-]+ # must start with string in the bracket [ ], must contains one or more (+) ( # start of group #1 \\.[_A-Za-z0-9-]+ # follow by a dot "." and string in the bracket [ ], must contains one or more (+) )* # end of group #1, this group is optional (*) @ # must contains a "@" symbol [A-Za-z0-9]+ # follow by string in the bracket [ ], must contains one or more (+) ( # start of group #2 - first level TLD checking \\.[A-Za-z0-9]+ # follow by a dot "." and string in the bracket [ ], must contains one or more (+) )* # end of group #2, this group is optional (*) ( # start of group #3 - second level TLD checking \\.[A-Za-z]{2,} # follow by a dot "." and string in the bracket [ ], with minimum length of 2 ) # end of group #3 $ #end of the line ([^\s]+(\.(?i)(jpg|png|gif|bmp))$ Image file extension ( #Start of the group #1 [^\s]+ # must contains one or more anything (except white space) ( # start of the group #2 \. # follow by a dot "." (?i) # ignore the case sensitive checking ( # start of the group #3 jpg # contains characters "jpg" | # ..or png # contains characters "png" | # ..or gif # contains characters "gif" | # ..or bmp # contains characters "bmp" ) # end of the group #3 ) # end of the group #2 $ # end of the string ) #end of the group # IP address ^([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\.([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\. ([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\.([01]?\\d\\d?|2[0-4]\\d|25[0-5])$ ^ #start of the line ( # start of group #1 [01]?\\d\\d? # Can be one or two digits. If three digits appear, it must start either 0 or 1 # e.g ([0-9], [0-9][0-9],[0-1][0-9][0-9]) | # ...or 2[0-4]\\d # start with 2, follow by 0-4 and end with any digit (2[0-4][0-9]) | # ...or 25[0-5] # start with 2, follow by 5 and end with 0-5 (25[0-5]) ) # end of group #2 \. # follow by a dot "." .... # repeat with 3 time (3x) $ #end of the line 12 hr TIME format (1[012]|[1-9]):[0-5][0-9](\\s)?(?i)(am|pm) ( #start of group #1 1[012] # start with 10, 11, 12 | # or [1-9] # start with 1,2,...9 ) #end of group #1 : # follow by a semi colon (:) [0-5][0-9] # follow by 0..5 and 0..9, which means 00 to 59 (\\s)? # follow by a white space (optional) (?i) # next checking is case insensitive (am|pm) # follow by am or pm 24hr time format ([01]?[0-9]|2[0-3]):[0-5][0-9] ( #start of group #1 [01]?[0-9] # start with 0-9,1-9,00-09,10-19 | # or 2[0-3] # start with 20-23 ) #end of group #1 : # follow by a semi colon (:) [0-5][0-9] # follow by 0..5 and 0..9, which means 00 to dat format dd/mm/yyyy (0?[1-9]|[12][0-9]|3[01])/(0?[1-9]|1[012])/((19|20)\\d\\d) #start of group #1 0?[1-9] # 01-09 or 1-9 | # ..or [12][0-9] # 10-19 or 20-29 | # ..or 3[01] # 30, 31 ) #end of group #1 / # follow by a "/" ( # start of group #2 0?[1-9] # 01-09 or 1-9 | # ..or 1[012] # 10,11,12 ) # end of group #2 / # follow by a "/" ( # start of group #3 (19|20)\\d\\d # 19[0-9][0-9] or 20[0-9][0-9] ) # end of group #3 html regular exprerssion <("[^"]*"|'[^']*'|[^'">])*> < #start with opening tag "<" ( # start of group #1 "[^"]*" # only two double quotes are allow - "string" | # ..or '[^']*' # only two single quotes are allow - 'string' | # ..or [^'">] # cant contains one single quotes, double quotes and ">" ) # end of group #1 * # 0 or more > #end with closing tag ">"For advanced regular expressions the java.util.regex.Pattern and java.util.regex.Matcher classes are used. You first create a Pattern object which defines the regular expression. This Pattern object allows you to create a Matcher object for a given string. This Matcher object then allows you to do regex operations on a String.