com.opensymphony.xwork2.util.WildcardUtil Maven / Gradle / Ivy
/*
* 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 com.opensymphony.xwork2.util;
import java.util.regex.Pattern;
/**
* Helper class to convert wildcard expression to regular expression
*/
public class WildcardUtil {
/**
* Convert wildcard pattern to Pattern
* @param pattern String containing wildcard pattern
* @return compiled regular expression as a Pattern
*/
public static Pattern compileWildcardPattern(String pattern) {
StringBuilder buf = new StringBuilder(pattern);
for (int i=buf.length()-1; i>=0; i--)
{
char c = buf.charAt(i);
if (c == '*' && (i == 0 || buf.charAt(i-1) != '\\'))
{
buf.insert(i+1, '?');
buf.insert(i, '.');
}
else if (c == '*')
{
i--; // skip backslash, too
}
else if (needsBackslashToBeLiteralInRegex(c))
{
buf.insert(i, '\\');
}
}
return Pattern.compile(buf.toString());
}
/**
* @param c character to test
* @return true if the given character must be escaped to be a literal
* inside a regular expression.
*/
private static final String theSpecialRegexCharList = ".[]\\?*+{}|()^$";
public static boolean needsBackslashToBeLiteralInRegex(
char c)
{
return (theSpecialRegexCharList.indexOf(c) >= 0);
}
}