org.opensearch.common.regex.Regex Maven / Gradle / Ivy
/*
* SPDX-License-Identifier: Apache-2.0
*
* The OpenSearch Contributors require contributions made to
* this file be licensed under the Apache-2.0 license or a
* compatible open source license.
*/
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.
*/
/*
* Modifications Copyright OpenSearch Contributors. See
* GitHub history for details.
*/
package org.opensearch.common.regex;
import org.apache.lucene.util.automaton.Automata;
import org.apache.lucene.util.automaton.Automaton;
import org.apache.lucene.util.automaton.Operations;
import org.opensearch.common.Strings;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import java.util.regex.Pattern;
public class Regex {
/**
* This Regex / {@link Pattern} flag is supported from Java 7 on.
* If set on a Java6 JVM the flag will be ignored.
*/
public static final int UNICODE_CHARACTER_CLASS = 0x100; // supported in JAVA7
/**
* Is the str a simple match pattern.
*/
public static boolean isSimpleMatchPattern(String str) {
return str.indexOf('*') != -1;
}
public static boolean isMatchAllPattern(String str) {
return str.equals("*");
}
/** Return an {@link Automaton} that matches the given pattern. */
public static Automaton simpleMatchToAutomaton(String pattern) {
List automata = new ArrayList<>();
int previous = 0;
for (int i = pattern.indexOf('*'); i != -1; i = pattern.indexOf('*', i + 1)) {
automata.add(Automata.makeString(pattern.substring(previous, i)));
automata.add(Automata.makeAnyString());
previous = i + 1;
}
automata.add(Automata.makeString(pattern.substring(previous)));
return Operations.concatenate(automata);
}
/**
* Return an Automaton that matches the union of the provided patterns.
*/
public static Automaton simpleMatchToAutomaton(String... patterns) {
if (patterns.length < 1) {
throw new IllegalArgumentException("There must be at least one pattern, zero given");
}
List automata = new ArrayList<>();
for (String pattern : patterns) {
automata.add(simpleMatchToAutomaton(pattern));
}
return Operations.union(automata);
}
/**
* Match a String against the given pattern, supporting the following simple
* pattern styles: "xxx*", "*xxx", "*xxx*" and "xxx*yyy" matches (with an
* arbitrary number of pattern parts), as well as direct equality.
* Matching is case sensitive.
*
* @param pattern the pattern to match against
* @param str the String to match
* @return whether the String matches the given pattern
*/
public static boolean simpleMatch(String pattern, String str) {
return simpleMatch(pattern, str, false);
}
/**
* Match a String against the given pattern, supporting the following simple
* pattern styles: "xxx*", "*xxx", "*xxx*" and "xxx*yyy" matches (with an
* arbitrary number of pattern parts), as well as direct equality.
*
* @param pattern the pattern to match against
* @param str the String to match
* @param caseInsensitive true if ASCII case differences should be ignored
* @return whether the String matches the given pattern
*/
public static boolean simpleMatch(String pattern, String str, boolean caseInsensitive) {
if (pattern == null || str == null) {
return false;
}
if (caseInsensitive) {
pattern = Strings.toLowercaseAscii(pattern);
str = Strings.toLowercaseAscii(str);
}
return simpleMatchWithNormalizedStrings(pattern, str);
}
private static boolean simpleMatchWithNormalizedStrings(String pattern, String str) {
int sIdx = 0, pIdx = 0, match = 0, wildcardIdx = -1;
while (sIdx < str.length()) {
// both chars matching, incrementing both pointers
if (pIdx < pattern.length() && str.charAt(sIdx) == pattern.charAt(pIdx)) {
sIdx++;
pIdx++;
} else if (pIdx < pattern.length() && pattern.charAt(pIdx) == '*') {
// wildcard found, only incrementing pattern pointer
wildcardIdx = pIdx;
match = sIdx;
pIdx++;
} else if (wildcardIdx != -1) {
// last pattern pointer was a wildcard, incrementing string pointer
pIdx = wildcardIdx + 1;
match++;
sIdx = match;
} else {
// current pattern pointer is not a wildcard, last pattern pointer was also not a wildcard
// characters do not match
return false;
}
}
// check for remaining characters in pattern
while (pIdx < pattern.length() && pattern.charAt(pIdx) == '*') {
pIdx++;
}
return pIdx == pattern.length();
}
/**
* Match a String against the given patterns, supporting the following simple
* pattern styles: "xxx*", "*xxx", "*xxx*" and "xxx*yyy" matches (with an
* arbitrary number of pattern parts), as well as direct equality.
*
* @param patterns the patterns to match against
* @param str the String to match
* @return whether the String matches any of the given patterns
*/
public static boolean simpleMatch(String[] patterns, String str) {
if (patterns != null) {
for (String pattern : patterns) {
if (simpleMatch(pattern, str)) {
return true;
}
}
}
return false;
}
/**
* Similar to {@link #simpleMatch(String[], String)}, but accepts a list of strings instead of an array of strings for the patterns to
* match.
*/
public static boolean simpleMatch(final List patterns, final String str) {
// #simpleMatch(String[], String) is likely to be inlined into this method
return patterns != null && simpleMatch(patterns.toArray(Strings.EMPTY_ARRAY), str);
}
public static boolean simpleMatch(String[] patterns, String[] types) {
if (patterns != null && types != null) {
for (String type : types) {
for (String pattern : patterns) {
if (simpleMatch(pattern, type)) {
return true;
}
}
}
}
return false;
}
public static Pattern compile(String regex, String flags) {
int pFlags = flags == null ? 0 : flagsFromString(flags);
return Pattern.compile(regex, pFlags);
}
public static int flagsFromString(String flags) {
int pFlags = 0;
for (String s : Strings.delimitedListToStringArray(flags, "|")) {
if (s.isEmpty()) {
continue;
}
s = s.toUpperCase(Locale.ROOT);
if ("CASE_INSENSITIVE".equals(s)) {
pFlags |= Pattern.CASE_INSENSITIVE;
} else if ("MULTILINE".equals(s)) {
pFlags |= Pattern.MULTILINE;
} else if ("DOTALL".equals(s)) {
pFlags |= Pattern.DOTALL;
} else if ("UNICODE_CASE".equals(s)) {
pFlags |= Pattern.UNICODE_CASE;
} else if ("CANON_EQ".equals(s)) {
pFlags |= Pattern.CANON_EQ;
} else if ("UNIX_LINES".equals(s)) {
pFlags |= Pattern.UNIX_LINES;
} else if ("LITERAL".equals(s)) {
pFlags |= Pattern.LITERAL;
} else if ("COMMENTS".equals(s)) {
pFlags |= Pattern.COMMENTS;
} else if (("UNICODE_CHAR_CLASS".equals(s)) || ("UNICODE_CHARACTER_CLASS".equals(s))) {
pFlags |= UNICODE_CHARACTER_CLASS;
} else {
throw new IllegalArgumentException("Unknown regex flag [" + s + "]");
}
}
return pFlags;
}
public static String flagsToString(int flags) {
StringBuilder sb = new StringBuilder();
if ((flags & Pattern.CASE_INSENSITIVE) != 0) {
sb.append("CASE_INSENSITIVE|");
}
if ((flags & Pattern.MULTILINE) != 0) {
sb.append("MULTILINE|");
}
if ((flags & Pattern.DOTALL) != 0) {
sb.append("DOTALL|");
}
if ((flags & Pattern.UNICODE_CASE) != 0) {
sb.append("UNICODE_CASE|");
}
if ((flags & Pattern.CANON_EQ) != 0) {
sb.append("CANON_EQ|");
}
if ((flags & Pattern.UNIX_LINES) != 0) {
sb.append("UNIX_LINES|");
}
if ((flags & Pattern.LITERAL) != 0) {
sb.append("LITERAL|");
}
if ((flags & Pattern.COMMENTS) != 0) {
sb.append("COMMENTS|");
}
if ((flags & UNICODE_CHARACTER_CLASS) != 0) {
sb.append("UNICODE_CHAR_CLASS|");
}
return sb.toString();
}
}
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