Make an optimization to store lower/upper case letters of target keys

[gavlyukovskiy]

This PR introduces an optimization to move toLowerCase conversion to the initialization time, so that we don't ever have to convert characters from original keys anymore.

Before:

Benchmark                               (jsonSize)  (maskedKeyProbability)  (obfuscationLength)   Mode  Cnt      Score   Error  Units
JsonMaskerBenchmark.baselineCountBytes       128kb                    0.01                 none  thrpt       23437,517          ops/s
JsonMaskerBenchmark.jacksonString            128kb                    0.01                 none  thrpt         499,279          ops/s
JsonMaskerBenchmark.jsonMaskerBytes          128kb                    0.01                 none  thrpt        3912,536          ops/s
JsonMaskerBenchmark.jsonMaskerString         128kb                    0.01                 none  thrpt        3673,244          ops/s

After:

Benchmark                               (jsonSize)  (maskedKeyProbability)  (obfuscationLength)   Mode  Cnt      Score   Error  Units
JsonMaskerBenchmark.baselineCountBytes       128kb                    0.01                 none  thrpt       23478,395          ops/s
JsonMaskerBenchmark.jacksonString            128kb                    0.01                 none  thrpt         487,419          ops/s
JsonMaskerBenchmark.jsonMaskerBytes          128kb                    0.01                 none  thrpt        5676,287          ops/s
JsonMaskerBenchmark.jsonMaskerString         128kb                    0.01                 none  thrpt        5332,056          ops/s

[sonarcloud]

Quality Gate passed

Kudos, no new issues were introduced!

0 New issues
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud