package time.zone; import java.util.ArrayList; import java.util.List; public class JavaNextCharacter { public static void main (String[] args) throws Exception { List<String> codes = new ArrayList<String>(); long started = System.currentTimeMillis(); String s1 = "IjKl", s2 = "P.R.I.T.O.M", s3 = "{AB374}", s4 = "{ZZ}{U8U}", s5 = "Tp9"; for (int i = 0; i < 20000; i++) { System.out.println(formatAsLength(("#" + (i + 1)), 10) + formatAsLength(s1, 7) + " " + formatAsLength(s2, 12) + " " + formatAsLength(s3, 10) + " " + formatAsLength(s4, 12) + " " + formatAsLength(s5, 10)); if (codes.contains(s1)) { throw new Exception("Duplicate code#1: " + s1 + " after generating " + codes.size() + " codes"); } else if (codes.contains(s2)) { throw new Exception("Duplicate code#2: " + s2 + " after generating " + codes.size() + " codes"); } else if (codes.contains(s3)) { throw new Exception("Duplicate code#3: " + s3 + " after generating " + codes.size() + " codes"); } else if (codes.contains(s4)) { throw new Exception("Duplicate code#4: " + s4 + " after generating " + codes.size() + " codes"); } else if (codes.contains(s5)) { throw new Exception("Duplicate code#5: " + s5 + " after generating " + codes.size() + " codes"); } codes.add(s1); codes.add(s2); codes.add(s3); codes.add(s4); codes.add(s5); s1 = next(s1); s2 = next(s2); s3 = next(s3); s4 = next(s4); s5 = next(s5); } System.out.println("Total time taken: " + (System.currentTimeMillis() - started) + " milli to generate" + " " + codes.size() + " codes"); } public static String next(String text) { int len = text.length(); if (len == 0) { return text; } boolean alphaNum = false; int alphaNumPos = -1; for (char c : text.toCharArray()) { alphaNumPos++; if (Character.isDigit(c) || Character.isLetter(c)) { alphaNum = true; break; } } StringBuilder buf = new StringBuilder(text); if (!alphaNum || alphaNumPos == 0 || alphaNumPos == len) { next(buf, buf.length() - 1, alphaNum); } else { String prefix = text.substring(0, alphaNumPos); buf = new StringBuilder(text.substring(alphaNumPos)); next(buf, buf.length() - 1, alphaNum); buf.insert(0, prefix); } return buf.toString(); } private static void next(StringBuilder buf, int pos, boolean alphaNum) { if (pos == -1) { char c = buf.charAt(0); String rep = null; if (Character.isDigit(c)) rep = "1"; else if (Character.isLowerCase(c)) rep = "a"; else if (Character.isUpperCase(c)) rep = "A"; else rep = Character.toString((char) (c + 1)); buf.insert(0, rep); return; } char c = buf.charAt(pos); if (Character.isDigit(c)) { if (c == '9') { buf.replace(pos, pos + 1, "0"); next(buf, pos - 1, alphaNum); } else { buf.replace(pos, pos + 1, Character.toString((char)(c + 1))); } } else if (Character.isLowerCase(c)) { if (c == 'z') { buf.replace(pos, pos + 1, "a"); next(buf, pos - 1, alphaNum); } else { buf.replace(pos, pos + 1, Character.toString((char)(c + 1))); } } else if (Character.isUpperCase(c)) { if (c == 'Z') { buf.replace(pos, pos + 1, "A"); next(buf, pos - 1, alphaNum); } else { buf.replace(pos, pos + 1, Character.toString((char)(c + 1))); } } else { if (alphaNum) { next(buf, pos - 1, alphaNum); } else { if (c == Character.MAX_VALUE) { buf.replace(pos, pos + 1, Character.toString(Character.MIN_VALUE)); next(buf, pos - 1, alphaNum); } else { buf.replace(pos, pos + 1, Character.toString((char)(c + 1))); } } } } public static String formatAsLength(String text, Integer minLength) { return String.format("%-" + minLength + "s", text); } }
#1 IjKl P.R.I.T.O.M {AB374} {ZZ}{U8U} Tp9
#2 IjKm P.R.I.T.O.N {AB375} {ZZ}{U8V} Tq0
#3 IjKn P.R.I.T.O.O {AB376} {ZZ}{U8W} Tq1
#4 IjKo P.R.I.T.O.P {AB377} {ZZ}{U8X} Tq2
#5 IjKp P.R.I.T.O.Q {AB378} {ZZ}{U8Y} Tq3
#6 IjKq P.R.I.T.O.R {AB379} {ZZ}{U8Z} Tq4
#7 IjKr P.R.I.T.O.S {AB380} {ZZ}{U9A} Tq5
#8 IjKs P.R.I.T.O.T {AB381} {ZZ}{U9B} Tq6
#9 IjKt P.R.I.T.O.U {AB382} {ZZ}{U9C} Tq7
#10 IjKu P.R.I.T.O.V {AB383} {ZZ}{U9D} Tq8
#11 IjKv P.R.I.T.O.W {AB384} {ZZ}{U9E} Tq9
#12 IjKw P.R.I.T.O.X {AB385} {ZZ}{U9F} Tr0
#13 IjKx P.R.I.T.O.Y {AB386} {ZZ}{U9G} Tr1
..................................
#19918 JmWm P.R.J.X.A.N {AV291} {AAC}{T4V} CSf6
#19919 JmWn P.R.J.X.A.O {AV292} {AAC}{T4W} CSf7
#19920 JmWo P.R.J.X.A.P {AV293} {AAC}{T4X} CSf8
#19921 JmWp P.R.J.X.A.Q {AV294} {AAC}{T4Y} CSf9
#19922 JmWq P.R.J.X.A.R {AV295} {AAC}{T4Z} CSg0
#19923 JmWr P.R.J.X.A.S {AV296} {AAC}{T5A} CSg1
#19924 JmWs P.R.J.X.A.T {AV297} {AAC}{T5B} CSg2
#19925 JmWt P.R.J.X.A.U {AV298} {AAC}{T5C} CSg3
#19926 JmWu P.R.J.X.A.V {AV299} {AAC}{T5D} CSg4
#19927 JmWv P.R.J.X.A.W {AV300} {AAC}{T5E} CSg5
#19928 JmWw P.R.J.X.A.X {AV301} {AAC}{T5F} CSg6
#19929 JmWx P.R.J.X.A.Y {AV302} {AAC}{T5G} CSg7
#19930 JmWy P.R.J.X.A.Z {AV303} {AAC}{T5H} CSg8
#19931 JmWz P.R.J.X.B.A {AV304} {AAC}{T5I} CSg9
#19932 JmXa P.R.J.X.B.B {AV305} {AAC}{T5J} CSh0
#19933 JmXb P.R.J.X.B.C {AV306} {AAC}{T5K} CSh1
#19934 JmXc P.R.J.X.B.D {AV307} {AAC}{T5L} CSh2
#19935 JmXd P.R.J.X.B.E {AV308} {AAC}{T5M} CSh3
#19936 JmXe P.R.J.X.B.F {AV309} {AAC}{T5N} CSh4
#19937 JmXf P.R.J.X.B.G {AV310} {AAC}{T5O} CSh5
#19938 JmXg P.R.J.X.B.H {AV311} {AAC}{T5P} CSh6
#19939 JmXh P.R.J.X.B.I {AV312} {AAC}{T5Q} CSh7
#19940 JmXi P.R.J.X.B.J {AV313} {AAC}{T5R} CSh8
#19941 JmXj P.R.J.X.B.K {AV314} {AAC}{T5S} CSh9
#19942 JmXk P.R.J.X.B.L {AV315} {AAC}{T5T} CSi0
#19943 JmXl P.R.J.X.B.M {AV316} {AAC}{T5U} CSi1
#19944 JmXm P.R.J.X.B.N {AV317} {AAC}{T5V} CSi2
#19945 JmXn P.R.J.X.B.O {AV318} {AAC}{T5W} CSi3
#19946 JmXo P.R.J.X.B.P {AV319} {AAC}{T5X} CSi4
#19947 JmXp P.R.J.X.B.Q {AV320} {AAC}{T5Y} CSi5
#19948 JmXq P.R.J.X.B.R {AV321} {AAC}{T5Z} CSi6
#19949 JmXr P.R.J.X.B.S {AV322} {AAC}{T6A} CSi7
#19950 JmXs P.R.J.X.B.T {AV323} {AAC}{T6B} CSi8
#19951 JmXt P.R.J.X.B.U {AV324} {AAC}{T6C} CSi9
#19952 JmXu P.R.J.X.B.V {AV325} {AAC}{T6D} CSj0
#19953 JmXv P.R.J.X.B.W {AV326} {AAC}{T6E} CSj1
#19954 JmXw P.R.J.X.B.X {AV327} {AAC}{T6F} CSj2
#19955 JmXx P.R.J.X.B.Y {AV328} {AAC}{T6G} CSj3
#19956 JmXy P.R.J.X.B.Z {AV329} {AAC}{T6H} CSj4
#19957 JmXz P.R.J.X.C.A {AV330} {AAC}{T6I} CSj5
#19958 JmYa P.R.J.X.C.B {AV331} {AAC}{T6J} CSj6
#19959 JmYb P.R.J.X.C.C {AV332} {AAC}{T6K} CSj7
#19960 JmYc P.R.J.X.C.D {AV333} {AAC}{T6L} CSj8
#19961 JmYd P.R.J.X.C.E {AV334} {AAC}{T6M} CSj9
#19962 JmYe P.R.J.X.C.F {AV335} {AAC}{T6N} CSk0
#19963 JmYf P.R.J.X.C.G {AV336} {AAC}{T6O} CSk1
#19964 JmYg P.R.J.X.C.H {AV337} {AAC}{T6P} CSk2
#19965 JmYh P.R.J.X.C.I {AV338} {AAC}{T6Q} CSk3
#19966 JmYi P.R.J.X.C.J {AV339} {AAC}{T6R} CSk4
#19967 JmYj P.R.J.X.C.K {AV340} {AAC}{T6S} CSk5
#19968 JmYk P.R.J.X.C.L {AV341} {AAC}{T6T} CSk6
#19969 JmYl P.R.J.X.C.M {AV342} {AAC}{T6U} CSk7
#19970 JmYm P.R.J.X.C.N {AV343} {AAC}{T6V} CSk8
#19971 JmYn P.R.J.X.C.O {AV344} {AAC}{T6W} CSk9
#19972 JmYo P.R.J.X.C.P {AV345} {AAC}{T6X} CSl0
#19973 JmYp P.R.J.X.C.Q {AV346} {AAC}{T6Y} CSl1
#19974 JmYq P.R.J.X.C.R {AV347} {AAC}{T6Z} CSl2
#19975 JmYr P.R.J.X.C.S {AV348} {AAC}{T7A} CSl3
#19976 JmYs P.R.J.X.C.T {AV349} {AAC}{T7B} CSl4
#19977 JmYt P.R.J.X.C.U {AV350} {AAC}{T7C} CSl5
#19978 JmYu P.R.J.X.C.V {AV351} {AAC}{T7D} CSl6
#19979 JmYv P.R.J.X.C.W {AV352} {AAC}{T7E} CSl7
#19980 JmYw P.R.J.X.C.X {AV353} {AAC}{T7F} CSl8
#19981 JmYx P.R.J.X.C.Y {AV354} {AAC}{T7G} CSl9
#19982 JmYy P.R.J.X.C.Z {AV355} {AAC}{T7H} CSm0
#19983 JmYz P.R.J.X.D.A {AV356} {AAC}{T7I} CSm1
#19984 JmZa P.R.J.X.D.B {AV357} {AAC}{T7J} CSm2
#19985 JmZb P.R.J.X.D.C {AV358} {AAC}{T7K} CSm3
#19986 JmZc P.R.J.X.D.D {AV359} {AAC}{T7L} CSm4
#19987 JmZd P.R.J.X.D.E {AV360} {AAC}{T7M} CSm5
#19988 JmZe P.R.J.X.D.F {AV361} {AAC}{T7N} CSm6
#19989 JmZf P.R.J.X.D.G {AV362} {AAC}{T7O} CSm7
#19990 JmZg P.R.J.X.D.H {AV363} {AAC}{T7P} CSm8
#19991 JmZh P.R.J.X.D.I {AV364} {AAC}{T7Q} CSm9
#19992 JmZi P.R.J.X.D.J {AV365} {AAC}{T7R} CSn0
#19993 JmZj P.R.J.X.D.K {AV366} {AAC}{T7S} CSn1
#19994 JmZk P.R.J.X.D.L {AV367} {AAC}{T7T} CSn2
#19995 JmZl P.R.J.X.D.M {AV368} {AAC}{T7U} CSn3
#19996 JmZm P.R.J.X.D.N {AV369} {AAC}{T7V} CSn4
#19997 JmZn P.R.J.X.D.O {AV370} {AAC}{T7W} CSn5
#19998 JmZo P.R.J.X.D.P {AV371} {AAC}{T7X} CSn6
#19999 JmZp P.R.J.X.D.Q {AV372} {AAC}{T7Y} CSn7
#20000 JmZq P.R.J.X.D.R {AV373} {AAC}{T7Z} CSn8
Total time taken: 74740 milli to generate 100000 codes
