deniskuzZ commented on code in PR #4998:
URL: https://github.com/apache/hive/pull/4998#discussion_r1535772006
##########
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/FilterStringColLikeStringScalar.java:
##########
@@ -140,4 +133,84 @@ public Checker tryCreate(String pattern) {
return new ComplexChecker("^" + UDFLike.likePatternToRegExp(pattern) +
"$");
}
}
+
+ /**
+ * Check the LIKE pattern..
+ */
+ private static class CheckerPattern {
+ private final String pattern;
+ private final UDFLike.PatternType type;
+
+ public CheckerPattern(UDFLike.PatternType type, String pattern) {
+ this.type = type;
+ this.pattern = pattern;
+ }
+
+ public String check() {
+ UDFLike.PatternType lastType = UDFLike.PatternType.NONE;
+ int length = pattern.length();
+ int beginIndex = 0;
+ int endIndex = length;
+ char lastChar = 0;
+ String strPattern = new String();
+ String simplePattern;
+
+ for (int i = 0; i < length; i++) {
Review Comment:
👍, do we have any benchmarks that prove efficiency of implemented algorithm?
also, usually for such kind of tasks (pattern matching) state machines are one
of the recommended techniques.
##########
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/FilterStringColLikeStringScalar.java:
##########
@@ -140,4 +133,84 @@ public Checker tryCreate(String pattern) {
return new ComplexChecker("^" + UDFLike.likePatternToRegExp(pattern) +
"$");
}
}
+
+ /**
+ * Check the LIKE pattern..
+ */
+ private static class CheckerPattern {
+ private final String pattern;
+ private final UDFLike.PatternType type;
+
+ public CheckerPattern(UDFLike.PatternType type, String pattern) {
+ this.type = type;
+ this.pattern = pattern;
+ }
+
+ public String check() {
+ UDFLike.PatternType lastType = UDFLike.PatternType.NONE;
+ int length = pattern.length();
+ int beginIndex = 0;
+ int endIndex = length;
+ char lastChar = 0;
+ String strPattern = new String();
+ String simplePattern;
+
+ for (int i = 0; i < length; i++) {
Review Comment:
👍, do we have any benchmarks that prove efficiency of implemented algorithm?
also, usually for such kind of tasks (pattern matching) state machines is one
of the recommended techniques.
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