package com.atlassian.plugin.webresource.transformer;
   
   import com.google.common.base.Function;
   
   import java.util.regex.Matcher;
   import java.util.regex.Pattern;
   
   /**
    * Performs a search and replace function on a given input.
   * @since 2.9.0
   */
  public class SearchAndReplacer
  {
      public static SearchAndReplacer create(final Pattern pattern, final Function<Matcher, CharSequence> replacer)
      {
          return new SearchAndReplacer(pattern, replacer);
      }
  
      private final Pattern pattern;
      private final Function<Matcher, CharSequence> replacer;
  
      /**
       * @param pattern the pattern to find in the input
       * @param replacer a function that gives replacement text for the given match
       */
      SearchAndReplacer(final Pattern pattern, final Function<Matcher, CharSequence> replacer)
      {
          this.pattern = pattern;
          this.replacer = replacer;
      }
  
      /**
       * Replace all occurrences of the pattern in the input, using the given function
       */
      public CharSequence replaceAll(final CharSequence input)
      {
          final Matcher matcher = pattern.matcher(input);
          final StringBuffer output = new StringBuffer();
          while (matcher.find())
          {
              final CharSequence sequence = replacer.apply(matcher);
              matcher.appendReplacement(output, "");
              output.append(sequence);
          }
          matcher.appendTail(output);
          return output;
      }
  }