Java Wildcard to Regex wildcardToRegexp(String globExp)

Description

Expands glob expressions to regular expressions.

License

Apache License

Parameter

Parameter	Description
globExp	the glob expression to expand

Return

a string with the regular expression this glob expands to

Declaration

public static String wildcardToRegexp(String globExp) 

Method Source Code

//package com.java2s;
/*/*w  w w  .ja v  a  2s  .com*/
 * 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.
 */

public class Main {
    /**
     * Expands glob expressions to regular expressions.
     *
     * @param globExp the glob expression to expand
     * @return a string with the regular expression this glob expands to
     */
    public static String wildcardToRegexp(String globExp) {
        StringBuilder dst = new StringBuilder();
        char[] src = globExp.replace("**/*", "**").toCharArray();
        int i = 0;
        while (i < src.length) {
            char c = src[i++];
            switch (c) {
            case '*':
                // One char lookahead for **
                if (i < src.length && src[i] == '*') {
                    dst.append(".*");
                    ++i;
                } else {
                    dst.append("[^/]*");
                }
                break;
            case '?':
                dst.append("[^/]");
                break;
            case '.':
            case '+':
            case '{':
            case '}':
            case '(':
            case ')':
            case '|':
            case '^':
            case '$':
                // These need to be escaped in regular expressions
                dst.append('\\').append(c);
                break;
            case '\\':
                i = doubleSlashes(dst, src, i);
                break;
            default:
                dst.append(c);
                break;
            }
        }
        return dst.toString();
    }

    private static int doubleSlashes(StringBuilder dst, char[] src, int i) {
        // Emit the next character without special interpretation
        dst.append('\\');
        if ((i - 1) != src.length) {
            dst.append(src[i]);
            i++;
        } else {
            // A backslash at the very end is treated like an escaped backslash
            dst.append('\\');
        }
        return i;
    }
}

Related

1. wildcardToRegex(final String pattern)
2. wildcardToRegex(String toSearch, boolean supportSQLWildcard)
3. wildcardToRegex(String wildcard)
4. wildcardToRegex(String wildcard)
5. wildcardToRegex(String wildcardPattern)
6. wildcardToRegexString(String wildcard)