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ProGuardCORE is a free library to read, analyze, modify, and write Java class files.
There is a newer version: 9.1.6
/*
 * ProGuardCORE -- library to process Java bytecode.
 *
 * Copyright (c) 2002-2020 Guardsquare NV
 *
 * Licensed 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 proguard.util;

import java.util.List;

/**
 * This {@link StringFunctionParser} can create {@link StringFunction} instances for regular
 * expressions. The created function returns a String, or null if it doesn't match. The regular
 * expressions are either presented as a list, or they are interpreted as comma-separated lists,
 * optionally prefixed with '!' negators. If an entry with a negator matches, a negative match is
 * returned, without considering any subsequent entries in the list. The creation of {@link
 * StringFunction} instances for the entries is delegated to the given {@link StringFunctionParser}.
 *
 * @author Eric Lafortune
 */
public class ListFunctionParser implements StringFunctionParser {
  private final StringFunctionParser stringFunctionParser;

  /**
   * Creates a new ListFunctionParser that parses individual elements in the comma-separated list
   * with the given StringFunctionParser.
   */
  public ListFunctionParser(StringFunctionParser stringFunctionParser) {
    this.stringFunctionParser = stringFunctionParser;
  }

  // Implementations for StringFunctionParser.

  public StringFunction parse(String regularExpression) {
    // Split the regular expression to a list and parse it.
    return parse(ListUtil.commaSeparatedList(regularExpression));
  }

  /**
   * Creates a StringFunction for the given regular expression, which can be a list of optionally
   * negated simple entries.
   *
   * An empty list results in a StringFunction that matches any string.
   */
  public StringFunction parse(List regularExpressions) {
    StringFunction listFunction = null;

    // Loop over all simple regular expressions, backward, creating a
    // linked list of functions.
    for (int index = regularExpressions.size() - 1; index >= 0; index--) {
      String regularExpression = (String) regularExpressions.get(index);

      StringFunction entryFunction = parseEntry(regularExpression);

      // Prepend the entry function.
      listFunction =
          listFunction == null
              ? entryFunction
              : isNegated(regularExpression)
                  ? new AndStringFunction(entryFunction, listFunction)
                  : new OrStringFunction(entryFunction, listFunction);
    }

    return listFunction == null ? StringFunction.IDENTITY_FUNCTION : listFunction;
  }

  // Small utility methods.

  /**
   * Creates a StringFunction for the given regular expression, which is a an optionally negated
   * simple expression.
   */
  private StringFunction parseEntry(String regularExpression) {
    // Wrap the matcher if the regular expression starts with a '!' negator.
    return isNegated(regularExpression)
        ? new NotStringFunction(stringFunctionParser.parse(regularExpression.substring(1)))
        : stringFunctionParser.parse(regularExpression);
  }

  /** Returns whether the given simple regular expression is negated. */
  private boolean isNegated(String regularExpression) {
    return regularExpression.length() > 0 && regularExpression.charAt(0) == '!';
  }

  /** A main method for testing name matching and replacement. */
  public static void main(String[] args) {
    try {
      System.out.println("Regular expression [" + args[0] + "]");
      WildcardManager wildcardManager = new WildcardManager();

      NameParser stringParser = new NameParser(wildcardManager);

      StringFunctionParser stringFunctionParser =
          new ListFunctionParser(new SingleFunctionParser(stringParser, wildcardManager));

      StringFunction function = stringFunctionParser.parse(args[0]);

      for (int index = 1; index < args.length; index++) {
        String string = args[index];
        System.out.print("String             [" + string + "]");
        System.out.println(" -> tranformed = " + function.transform(args[index]));
      }
    } catch (Exception ex) {
      ex.printStackTrace();
    }
  }
}