001/** 002 * Logback: the reliable, generic, fast and flexible logging framework. 003 * Copyright (C) 1999-2015, QOS.ch. All rights reserved. 004 * 005 * This program and the accompanying materials are dual-licensed under 006 * either the terms of the Eclipse Public License v1.0 as published by 007 * the Eclipse Foundation 008 * 009 * or (per the licensee's choosing) 010 * 011 * under the terms of the GNU Lesser General Public License version 2.1 012 * as published by the Free Software Foundation. 013 */ 014package ch.qos.logback.core.util; 015 016import java.text.SimpleDateFormat; 017import java.util.ArrayList; 018import java.util.List; 019 020/** 021 * This class is concerned with computing a regex corresponding to a date 022 * pattern (in {@link SimpleDateFormat} format). 023 * 024 * @author Ceki Gülcü 025 */ 026public class DatePatternToRegexUtil { 027 028 final String datePattern; 029 final int datePatternLength; 030 final CharSequenceToRegexMapper regexMapper = new CharSequenceToRegexMapper(); 031 032 public DatePatternToRegexUtil(String datePattern) { 033 this.datePattern = datePattern; 034 datePatternLength = datePattern.length(); 035 } 036 037 public String toRegex() { 038 List<CharSequenceState> charSequenceList = tokenize(); 039 StringBuilder sb = new StringBuilder(); 040 for (CharSequenceState seq : charSequenceList) { 041 sb.append(regexMapper.toRegex(seq)); 042 } 043 return sb.toString(); 044 } 045 046 private List<CharSequenceState> tokenize() { 047 List<CharSequenceState> sequenceList = new ArrayList<CharSequenceState>(); 048 049 CharSequenceState lastCharSequenceState = null; 050 051 for (int i = 0; i < datePatternLength; i++) { 052 char t = datePattern.charAt(i); 053 if (lastCharSequenceState == null || lastCharSequenceState.c != t) { 054 lastCharSequenceState = new CharSequenceState(t); 055 sequenceList.add(lastCharSequenceState); 056 } else { 057 lastCharSequenceState.incrementOccurrences(); 058 } 059 } 060 return sequenceList; 061 } 062}