org.smallmind.nutsnbolts.io.RegExTranslator Maven / Gradle / Ivy

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/*
 * Copyright (c) 2007 through 2024 David Berkman
 *
 * This file is part of the SmallMind Code Project.
 *
 * The SmallMind Code Project is free software, you can redistribute
 * it and/or modify it under either, at your discretion...
 *
 * 1) The terms of GNU Affero General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at
 * your option) any later version.
 *
 * ...or...
 *
 * 2) The terms of the Apache License, Version 2.0.
 *
 * The SmallMind Code Project is distributed in the hope that it will
 * be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License or Apache License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * and the Apache License along with the SmallMind Code Project. If not, see
 *  or .
 *
 * Additional permission under the GNU Affero GPL version 3 section 7
 * ------------------------------------------------------------------
 * If you modify this Program, or any covered work, by linking or
 * combining it with other code, such other code is not for that reason
 * alone subject to any of the requirements of the GNU Affero GPL
 * version 3.
 */
package org.smallmind.nutsnbolts.io;

public class RegExTranslator {

  public static String translate (String pattern) {

    StringBuilder patternBuilder = new StringBuilder();
    boolean isStar = false;

    for (int index = 0; index < pattern.length(); index++) {
      if (isStar && (pattern.charAt(index) != '*')) {
        patternBuilder.append("[^/]*");
        isStar = false;
      }

      switch (pattern.charAt(index)) {
        case '$':
          patternBuilder.append("\\$");
        case '.':
          patternBuilder.append("\\.");
          break;
        case '*':
          if (isStar) {
            patternBuilder.append(".*");
            isStar = false;
          } else {
            isStar = true;
          }
          break;
        case '?':
          patternBuilder.append("[^/]?");
          break;
        default:
          patternBuilder.append(pattern.charAt(index));
      }
    }

    if (isStar) {
      patternBuilder.append("[^/]*");
    }

    return patternBuilder.toString();
  }
}