protected void initialize()

in src/main/java/org/apache/log4j/receivers/varia/LogFilePatternReceiver.java [607:728]
91 lines of code
25 McCabe index (conditional complexity)

  protected void initialize() {
	if (host == null && path == null) {
		try {
			URL url = new URL(fileURL);
			host = url.getHost();
			path = url.getPath();
		} catch (MalformedURLException e1) {
			// TODO Auto-generated catch block
			e1.printStackTrace();
		}
	}
	if (host == null || host.trim().equals("")) {
		host = DEFAULT_HOST;
	}
	if (path == null || path.trim().equals("")) {
		path = fileURL;
	}

    currentMap = new HashMap();
    additionalLines = new ArrayList();
    matchingKeywords = new ArrayList();

    if (timestampFormat != null) {
      dateFormat = new SimpleDateFormat(quoteTimeStampChars(timestampFormat));
      timestampPatternText = convertTimestamp();
    }
    //if custom level definitions exist, parse them
    updateCustomLevelDefinitionMap();
    try {
      if (filterExpression != null) {
        expressionRule = ExpressionRule.getRule(filterExpression);
      }
    } catch (Exception e) {
      getLogger().warn("Invalid filter expression: " + filterExpression, e);
    }

    List buildingKeywords = new ArrayList();

    String newPattern = logFormat;

    int index = 0;
    String current = newPattern;
    //build a list of property names and temporarily replace the property with an empty string,
    //we'll rebuild the pattern later
    List propertyNames = new ArrayList();
    while (index > -1) {
        if (current.indexOf(PROP_START) > -1 && current.indexOf(PROP_END) > -1) {
            index = current.indexOf(PROP_START);
            String longPropertyName = current.substring(current.indexOf(PROP_START), current.indexOf(PROP_END) + 1);
            String shortProp = getShortPropertyName(longPropertyName);
            buildingKeywords.add(shortProp);
            propertyNames.add(longPropertyName);
            current = current.substring(longPropertyName.length() + 1 + index);
            newPattern = singleReplace(newPattern, longPropertyName, new Integer(buildingKeywords.size() -1).toString());
        } else {
            //no properties
            index = -1;
        }
    }

    /*
     * we're using a treemap, so the index will be used as the key to ensure
     * keywords are ordered correctly
     *
     * examine pattern, adding keywords to an index-based map patterns can
     * contain only one of these per entry...properties are the only 'keyword'
     * that can occur multiple times in an entry
     */
    Iterator iter = keywords.iterator();
    while (iter.hasNext()) {
      String keyword = (String) iter.next();
      int index2 = newPattern.indexOf(keyword);
      if (index2 > -1) {
        buildingKeywords.add(keyword);
        newPattern = singleReplace(newPattern, keyword, new Integer(buildingKeywords.size() -1).toString());
      }
    }

    String buildingInt = "";

    for (int i=0;i<newPattern.length();i++) {
        String thisValue = String.valueOf(newPattern.substring(i, i+1));
        if (isInteger(thisValue)) {
            buildingInt = buildingInt + thisValue;
        } else {
            if (isInteger(buildingInt)) {
                matchingKeywords.add(buildingKeywords.get(Integer.parseInt(buildingInt)));
            }
            //reset
            buildingInt = "";
        }
    }

    //if the very last value is an int, make sure to add it
    if (isInteger(buildingInt)) {
        matchingKeywords.add(buildingKeywords.get(Integer.parseInt(buildingInt)));
    }

    newPattern = replaceMetaChars(newPattern);

    //compress one or more spaces in the pattern into the [ ]+ regexp
    //(supports padding of level in log files)
    newPattern = newPattern.replaceAll(MULTIPLE_SPACES_REGEXP, MULTIPLE_SPACES_REGEXP);
    newPattern = newPattern.replaceAll(Pattern.quote(PATTERN_WILDCARD), REGEXP_DEFAULT_WILDCARD);
    //use buildingKeywords here to ensure correct order
    for (int i = 0;i<buildingKeywords.size();i++) {
      String keyword = (String) buildingKeywords.get(i);
      //make the final keyword greedy (we're assuming it's the message)
      if (i == (buildingKeywords.size() - 1)) {
        newPattern = singleReplace(newPattern, String.valueOf(i), GREEDY_GROUP);
      } else if (TIMESTAMP.equals(keyword)) {
        newPattern = singleReplace(newPattern, String.valueOf(i), "(" + timestampPatternText + ")");
      } else if (LOGGER.equals(keyword) || LEVEL.equals(keyword)) {
        newPattern = singleReplace(newPattern, String.valueOf(i), NOSPACE_GROUP);
      } else {
        newPattern = singleReplace(newPattern, String.valueOf(i), DEFAULT_GROUP);
      }
    }

    regexp = newPattern;
    getLogger().debug("regexp is " + regexp);
  }