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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.spark.sql.catalyst.util
import java.util.regex.{Pattern, PatternSyntaxException}
import org.apache.spark.unsafe.types.UTF8String
object StringUtils {
/** Convert 'like' pattern to Java regex. */
def escapeLikeRegex(str: String): String = {
val in = str.toIterator
val out = new StringBuilder()
while (in.hasNext) {
in.next match {
case '\\' if in.hasNext =>
in.next match {
case '\\' => out ++= Pattern.quote("\\")
case '_' => out ++= Pattern.quote("_")
case '%' => out ++= Pattern.quote("%")
// escape before non-escapable character treated literally
case c => out ++= Pattern.quote("\\" + c)
}
case '_' => out ++= "."
case '%' => out ++= ".*"
case c => out ++= Pattern.quote(Character.toString(c))
}
}
"(?s)" + out.result() // (?s) enables dotall mode, causing "." to match new lines
}
private[this] val trueStrings = Set("t", "true", "y", "yes", "1").map(UTF8String.fromString)
private[this] val falseStrings = Set("f", "false", "n", "no", "0").map(UTF8String.fromString)
def isTrueString(s: UTF8String): Boolean = trueStrings.contains(s.toLowerCase)
def isFalseString(s: UTF8String): Boolean = falseStrings.contains(s.toLowerCase)
/**
* This utility can be used for filtering pattern in the "Like" of "Show Tables / Functions" DDL
* @param names the names list to be filtered
* @param pattern the filter pattern, only '*' and '|' are allowed as wildcards, others will
* follow regular expression convention, case insensitive match and white spaces
* on both ends will be ignored
* @return the filtered names list in order
*/
def filterPattern(names: Seq[String], pattern: String): Seq[String] = {
val funcNames = scala.collection.mutable.SortedSet.empty[String]
pattern.trim().split("\\|").foreach { subPattern =>
try {
val regex = ("(?i)" + subPattern.replaceAll("\\*", ".*")).r
funcNames ++= names.filter{ name => regex.pattern.matcher(name).matches() }
} catch {
case _: PatternSyntaxException =>
}
}
funcNames.toSeq
}
}
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