package org.bitbucket.jrsofty.parser.logging.api;
   
   import java.util.regex.Matcher;
   import java.util.regex.Pattern;
   
   /**
    * A container class for holding the regex pattern and token marker used for mapping the token.
    *
    * @author jrsofty
   *
   */
  public class TokenMatcher {
  
    private final Pattern regexPattern;
    private final String tokenMarker;
  
    public TokenMatcher(final String regex, final String tokenMarker) {
      this.tokenMarker = tokenMarker;
      this.regexPattern = Pattern.compile(regex);
    }
  
    /**
     * The regex pattern that was used for creating the regex used.
     * 
     * @return the regex pattern as String.
     */
    public String getPattern() {
      return this.regexPattern.toString();
    }
  
    /**
     * Delivers the token marker used for mapping. Token markers are not always exactly as they were
     * entered in the formatting string. Every token marker will be extended with an instance number.
     * 
     * @return this TokenMatcher's token marker.
     */
    public String getTokenMarker() {
      return this.tokenMarker;
    }
  
    /**
     * Validates the given token with the compiled regex pattern. Returns null if there is not a
     * match.
     *
     * @param token
     *          a portion of the log line as String
     * @return the token value if a match, otherwise returns null.
     * @throws TokenParseException
     *           when a match fails.
     */
    public String validateToken(final String token) throws TokenParseException {
  
      final Matcher matcher = this.regexPattern.matcher(token);
      matcher.find();
      try {
        final String result = matcher.group(0);
        return result;
      } catch (final IllegalStateException e) {
        throw new TokenParseException(token, this.tokenMarker, this.regexPattern.toString(), e);
      }
  
    }
  
  }