java - Regex Illegal Argument Exception -

i using disklrucache jake wharton , experiencing issue creating keys , formatting them libraries specific regex.

1) according library, keys must conform [a-z0-9_-]{1,64}.

2) code using format keys:

string key = url.replace(".", "-")             .replaceall("^[a-z0-9_-]", "")             .tolowercase();  if(key.length() > 63)     key = key.substring(key.length() - 63, key.length());  log.d(tag, "key: " + key);  disklrucache.snapshot snapshot = mdiskcache.get(key); 

3) code disklrucache using validate keys

static final string string_key_pattern = "[a-z0-9_-]{1,120}"; static final pattern legal_key_pattern = pattern.compile(string_key_pattern);  private void validatekey(string key) {     matcher matcher = legal_key_pattern.matcher(key);     if (!matcher.matches()) {       throw new illegalargumentexception("keys must match regex "               + string_key_pattern + ": \"" + key + "\"");     }   } 

4) , here of keys users getting throwing iaexception:

54 | 00:00:02:227 | d/asset manager key: a9e9b46-e476-fdd1rx0y0w500h325r_330000_000-mp4 59 | 00:00:07:132 | d/asset manager key: 5f54b52-2ef9-3420rx0y0w135h156r_00cc00_120-mp4 64 | 00:00:08:665 | d/asset manager key: 6c705f7-c0b8-1235rx0y0w395h314r_000033_240-mp4 69 | 00:00:08:984 | d/asset manager key: 7cdb2b3-f0f7-2c76rx0y0w500h153r_cccccc_000-mp4 74 | 00:00:09:477 | d/asset manager key: 5f54b52-2ef9-3420rx0y0w135h156r_00cc00_120-mp4 79 | 00:00:14:999 | d/asset manager key: a91dcba-07a4-58ccrx0y0w227h199r_663300_040-mp4 84 | 00:00:18:176 | d/asset manager key: 5aad806-70a0-6426rx0y0w500h200r_333300_060-mp4 89 | 00:00:25:499 | d/asset manager key: 8e7b5b5-eb57-2f6erx0y0w500h333r_cccc99_060-mp4 94 | 00:00:26:262 | d/asset manager key: a1fa904-3f87-4ee7rx0y0w498h281r_330066_280-mp4 99 | 00:00:29:370 | d/asset manager key: a1fa904-b01f-8ca8rx0y0w404h273r_663333_000-mp4 104 | 00:00:33:981 | d/asset manager key: 0d8298c-7922-8914rx0y0w242h140r_3366cc_220-mp4 109 | 00:00:36:839 | d/asset manager key: 2577a4b-88ea-8282rx0y0w500h372r_333300_060-mp4 114 | 00:00:40:294 | d/asset manager key: 6c20180-1454-b7e4rx0y0w500h273r_330066_280-mp4 119 | 00:00:44:582 | d/asset manager key: toilet_flush_ani_ef1405f6-c75a-aa6f-a5f29f1085e8a151-gif 124 | 00:00:45:149 | d/asset manager key: a5097fb-7f16-fea5rx0y0w299h296r_996633_040-mp4 129 | 00:00:48:491 | d/asset manager key: 25773d1-7499-5fecrx0y0w500h210r_996633_040-mp4 134 | 00:00:52:509 | d/asset manager key: 2e78ac2-e675-95b5rx0y0w500h281r_cccccc_000-mp4 139 | 00:00:55:684 | d/asset manager key: a91dcba-c029-01a1rx0y0w380h177r_663300_040-mp4 144 | 00:00:56:848 | d/asset manager key: a215a90-996d-850erx0y0w500h250r_cccccc_000-mp4 196 | 00:00:57:476 | d/asset manager key: 82369cc-0a2f-4be8rx0y0w280h210r_330000_000-mp4 201 | 00:00:58:393 | d/asset manager key: a1fa904-09fe-25berx0y0w320h240r_330000_000-mp4 206 | 00:01:05:755 | d/asset manager key: a3f8891-f017-cf00rx0y0w500h250r_cc9933_040-mp4 211 | 00:01:07:640 | d/asset manager key: 6890e6e-4c44-fa27rx0y0w500h325r_006600_120-mp4 216 | 00:01:10:147 | d/asset manager key: a215a90-2e33-ab4erx0y0w500h375r_996633_040-mp4 221 | 00:01:12:938 | d/asset manager key: 2e78ac2-5541-5c23rx0y0w500h243r_cccccc_000-mp4 226 | 00:01:14:499 | d/asset manager key: 02a9b27-3e20-4a6drx0y0w325h429r_cccccc_000-mp4 231 | 00:01:16:610 | d/asset manager key: a9534a9-2abc-572frx0y0w500h349r_333300_060-mp4 236 | 00:01:18:263 | d/asset manager key: a9f17f7-dceb-46fbrx0y0w50h50r_cc9933_040-mp4 

the issue seems regex pattern used sanitize keys.

when use .replaceall("^[a-z0-9_-]", ""), it removes first symbol in string: letter or digit or underscore or hyphen.

to remove characters other in class, use negated character class - place caret right after opening square bracket:

string key = url.replace(".", "-")            .replaceall("[^a-z0-9_-]", "");