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    1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one or more
    3    * contributor license agreements. See the NOTICE file distributed with
    4    * this work for additional information regarding copyright ownership.
    5    * The ASF licenses this file to You under the Apache license, Version 2.0
    6    * (the "License"); you may not use this file except in compliance with
    7    * the License. You may obtain a copy of the License at
    8    *
    9    *      http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the license for the specific language governing permissions and
    15   * limitations under the license.
    16   */
    17  package org.apache.logging.log4j.core.pattern;
    18
    19  import java.util.regex.Pattern;
    20
    21  import org.apache.logging.log4j.Logger;
    22  import org.apache.logging.log4j.core.config.plugins.Plugin;
    23  import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
    24  import org.apache.logging.log4j.core.config.plugins.PluginFactory;
    25  import org.apache.logging.log4j.status.StatusLogger;
    26
    27  /**
    28   * Replace tokens in the LogEvent message.
    29   */
    30  @Plugin(name = "replace", category = "Core", printObject = true)
    31  public final class RegexReplacement {
    32
    33      private static final Logger LOGGER = StatusLogger.getLogger();
    34
    35      private final Pattern pattern;
    36
    37      private final String substitution;
    38
    39      /**
    40       * Private constructor.
    41       *
    42       * @param pattern The Pattern.
    43       * @param substitution The substitution String.
    44       */
    45      private RegexReplacement(final Pattern pattern, final String substitution) {
    46          this.pattern = pattern;
    47          this.substitution = substitution;
    48      }
    49
    50      /**
    51       * Perform the replacement.
    52       * @param msg The String to match against.
    53       * @return the replacement String.
    54       */
    55      public String format(final String msg) {
    56          return pattern.matcher(msg).replaceAll(substitution);
    57      }
    58
    59      @Override
    60      public String toString() {
    61          return "replace(regex=" + pattern.pattern() + ", replacement=" + substitution + ')';
    62      }
    63
    64      /**
    65       * Create a RegexReplacement.
    66       * @param regex The regular expression to locate.
    67       * @param replacement The replacement value.
    68       * @return A RegexReplacement.
    69       */
    70      @PluginFactory
    71      public static RegexReplacement createRegexReplacement(
    72              @PluginAttribute("regex") final Pattern regex,
    73              @PluginAttribute("replacement") final String replacement) {
    74          if (regex == null) {
    75              LOGGER.error("A regular expression is required for replacement");
    76              return null;
    77          }
    78          if (replacement == null) {
    79              LOGGER.error("A replacement string is required to perform replacement");
    80          }
    81          // FIXME: should we use Matcher.quoteReplacement() here?
    82          return new RegexReplacement(regex, replacement);
    83      }
    84
    85  }