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comparison src/main/java/org/monetdb/jdbc/MonetDatabaseMetaData.java @ 680:238d6a3a6469

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Improve composeMatchPart(final String in). Prevent parsing pattern when length is 0. Optimise patterns: % or %%.
author Martin van Dinther <martin.van.dinther@monetdbsolutions.com>
date Thu, 03 Nov 2022 19:45:52 +0100 (2022-11-03)
parents 3034312c1eda
children 78253fdb3c3f
comparison
equal deleted inserted replaced
679:a2dfec33dbcb 680:238d6a3a6469
4238 */ 4238 */
4239 private final String composeMatchPart(final String in) { 4239 private final String composeMatchPart(final String in) {
4240 if (in == null) 4240 if (in == null)
4241 return "IS NULL"; 4241 return "IS NULL";
4242 4242
4243 final int len = in.length();
4244 if (len == 0)
4245 return "= ''";
4246
4247 if (in.equals("%") || in.equals("%%"))
4248 return "LIKE '%'";
4249
4243 // Scan input string for SQL wildcard characters: % and _ 4250 // Scan input string for SQL wildcard characters: % and _
4244 // When they are all prefixed by a backslash then the backslash is removed (to allow usage of = comparator) 4251 // When they are all prefixed by a backslash then the backslash is removed (to allow usage of = comparator)
4245 // else it needs to be interpreted as a wildcard and we need to use LIKE instead of = comparator. 4252 // else it needs to be interpreted as a wildcard and we need to use LIKE instead of = comparator.
4246 // A backslash can be escaped by using two backslashes. 4253 // A backslash can be escaped by using two backslashes.
4247 final int len = in.length();
4248 final StringBuilder sb = new StringBuilder(len); 4254 final StringBuilder sb = new StringBuilder(len);
4249 boolean removed_bs = false; 4255 boolean removed_bs = false;
4250 boolean use_like = false; 4256 boolean use_like = false;
4251 boolean escaped = false; 4257 boolean escaped = false;
4252 try { 4258 try {
4294 return "LIKE " + MonetWrapper.sq(in); 4300 return "LIKE " + MonetWrapper.sq(in);
4295 } 4301 }
4296 if (removed_bs) { 4302 if (removed_bs) {
4297 // for debug: System.out.println("input: " + in + " changed into: " + "= " + MonetWrapper.sq(sb.toString())); 4303 // for debug: System.out.println("input: " + in + " changed into: " + "= " + MonetWrapper.sq(sb.toString()));
4298 // we found only escaped wildcard character(s), 4304 // we found only escaped wildcard character(s),
4299 // use the edited string without the ecapes before the wildcard character(s) so an equals match can be done (its is faster than LIKE) 4305 // use the edited string without the ecapes before the wildcard character(s) so an equals match can be done (which is faster than LIKE)
4300 return "= " + MonetWrapper.sq(sb.toString()); 4306 return "= " + MonetWrapper.sq(sb.toString());
4301 } 4307 }
4302 // for debug: System.out.println("input: " + in + " changed into: " + "= " + MonetWrapper.sq(in)); 4308 // for debug: System.out.println("input: " + in + " changed into: " + "= " + MonetWrapper.sq(in));
4303 return "= " + MonetWrapper.sq(in); 4309 return "= " + MonetWrapper.sq(in);
4304 } 4310 }