Question

I need to filter out the strings which matches with [LCK_ or OPN_] only at the starting of file name, but not to consider any where else.

Example source strings:

LCK_card_L02NOR19999_2012-11-07-121600 [Invalid/Filter it]
BLTM_L183ROP3289_2012-11-07-121601 [Valid one]
TEMP_LCK_card_L02NOR19999_2012-11-07-121600 [Valid one]

I tried like this:

LCK_|OPN_

But it’s also matching TEMP_LCK_XXXXX.

how do I combine the patterns for my rquriement [ignore LCK_ or OPN_ and extract date]?

My regex pattern for date extraction

(19|20)\\d\\d[-](0[1-9]|1[012])[-](0[1-9]|[12][0-9]|3[01])[-]\\d\\d\\d\\d\\d\\d]

Answer 1

Consider this code:

String[] strs = new String[] {
    "LCK_card_L02NOR19999_2012-11-07-121600", // Invalid
    "BLTM_L183ROP3289_2012-11-07-121601", // Valid one
    "TEMP_LCK_card_L02NOR19999_2012-11-07-121600" // Valid one
};

String pattern = "^(?!(LCK_|OPN_))(.*)((19|20)[0-9]{2}-(0[1-9]|1[012])-(0[1-9]|[12][0-9]|3[01])-[0-9]{6}).*";

for (String string : strs) {
    boolean m = string.matches(pattern);
    System.out.println(m ? "Valid" : "Invalid");
}

This will match first the start of the string (denoted by ^), then anything except LCK_ or OPN_ (denoted by ?!), then 0 or more arbitrary characters, then your date pattern, then possibly a number of characters.