/*
* 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.
*/
package org.elasticsearch.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.elasticsearch.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<Automaton> 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<Automaton> 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.
*
* @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) {
if (pattern == null || str == null) {
return false;
}
int firstIndex = pattern.indexOf('*');
if (firstIndex == -1) {
return pattern.equals(str);
}
if (firstIndex == 0) {
if (pattern.length() == 1) {
return true;
}
int nextIndex = pattern.indexOf('*', firstIndex + 1);
if (nextIndex == -1) {
return str.endsWith(pattern.substring(1));
} else if (nextIndex == 1) {
// Double wildcard "**" - skipping the first "*"
return simpleMatch(pattern.substring(1), str);
}
String part = pattern.substring(1, nextIndex);
int partIndex = str.indexOf(part);
while (partIndex != -1) {
if (simpleMatch(pattern.substring(nextIndex), str.substring(partIndex + part.length()))) {
return true;
}
partIndex = str.indexOf(part, partIndex + 1);
}
return false;
}
return (str.length() >= firstIndex &&
pattern.substring(0, firstIndex).equals(str.substring(0, firstIndex)) &&
simpleMatch(pattern.substring(firstIndex), str.substring(firstIndex)));
}
/**
* 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;
}
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();
}
}