openwire-core/src/main/java/org/apache/activemq/openwire/utils/CronParser.java - activemq-openwire - Git at Google

 /**
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
  * The ASF licenses this file to You under the Apache License, Version 2.0
  * (the "License"); you may not use this file except in compliance with
  * the License.  You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 package org.apache.activemq.openwire.utils;

 import java.util.ArrayList;
 import java.util.Calendar;
 import java.util.Collections;
 import java.util.List;
 import java.util.StringTokenizer;

 import javax.jms.MessageFormatException;

 public class CronParser {

     private static final int NUMBER_TOKENS = 5;
     private static final int MINUTES = 0;
     private static final int HOURS = 1;
     private static final int DAY_OF_MONTH = 2;
     private static final int MONTH = 3;
     private static final int DAY_OF_WEEK = 4;

     public static long getNextScheduledTime(final String cronEntry, long currentTime) throws MessageFormatException {

         long result = 0;

         if (cronEntry == null || cronEntry.length() == 0) {
             return result;
         }

         // Handle the once per minute case "* * * * *"
         // starting the next event at the top of the minute.
         if (cronEntry.equals("* * * * *")) {
             result = currentTime + 60 * 1000;
             result = result / 60000 * 60000;
             return result;
         }

         List<String> list = tokenize(cronEntry);
         List<CronEntry> entries = buildCronEntries(list);
         Calendar working = Calendar.getInstance();
         working.setTimeInMillis(currentTime);
         working.set(Calendar.SECOND, 0);

         CronEntry minutes = entries.get(MINUTES);
         CronEntry hours = entries.get(HOURS);
         CronEntry dayOfMonth = entries.get(DAY_OF_MONTH);
         CronEntry month = entries.get(MONTH);
         CronEntry dayOfWeek = entries.get(DAY_OF_WEEK);

         // Start at the top of the next minute, cron is only guaranteed to be
         // run on the minute.
         int timeToNextMinute = 60 - working.get(Calendar.SECOND);
         working.add(Calendar.SECOND, timeToNextMinute);

         // If its already to late in the day this will roll us over to tomorrow
         // so we'll need to check again when done updating month and day.
         int currentMinutes = working.get(Calendar.MINUTE);
         if (!isCurrent(minutes, currentMinutes)) {
             int nextMinutes = getNext(minutes, currentMinutes);
             working.add(Calendar.MINUTE, nextMinutes);
         }

         int currentHours = working.get(Calendar.HOUR_OF_DAY);
         if (!isCurrent(hours, currentHours)) {
             int nextHour = getNext(hours, currentHours);
             working.add(Calendar.HOUR_OF_DAY, nextHour);
         }

         // We can roll into the next month here which might violate the cron setting
         // rules so we check once then recheck again after applying the month settings.
         doUpdateCurrentDay(working, dayOfMonth, dayOfWeek);

         // Start by checking if we are in the right month, if not then calculations
         // need to start from the beginning of the month to ensure that we don't end
         // up on the wrong day. (Can happen when DAY_OF_WEEK is set and current time
         // is ahead of the day of the week to execute on).
         doUpdateCurrentMonth(working, month);

         // Now Check day of week and day of month together since they can be specified
         // together in one entry, if both "day of month" and "day of week" are restricted
         // (not "*"), then either the "day of month" field (3) or the "day of week" field
         // (5) must match the current day or the Calenday must be advanced.
         doUpdateCurrentDay(working, dayOfMonth, dayOfWeek);

         // Now we can chose the correct hour and minute of the day in question.

         currentHours = working.get(Calendar.HOUR_OF_DAY);
         if (!isCurrent(hours, currentHours)) {
             int nextHour = getNext(hours, currentHours);
             working.add(Calendar.HOUR_OF_DAY, nextHour);
         }

         currentMinutes = working.get(Calendar.MINUTE);
         if (!isCurrent(minutes, currentMinutes)) {
             int nextMinutes = getNext(minutes, currentMinutes);
             working.add(Calendar.MINUTE, nextMinutes);
         }

         result = working.getTimeInMillis();

         if (result <= currentTime) {
             throw new ArithmeticException("Unable to compute next scheduled exection time.");
         }

         return result;
     }

     protected static long doUpdateCurrentMonth(Calendar working, CronEntry month) throws MessageFormatException {
         int currentMonth = working.get(Calendar.MONTH) + 1;
         if (!isCurrent(month, currentMonth)) {
             int nextMonth = getNext(month, currentMonth);
             working.add(Calendar.MONTH, nextMonth);

             // Reset to start of month.
             resetToStartOfDay(working, 1);

             return working.getTimeInMillis();
         }

         return 0L;
     }

     protected static long doUpdateCurrentDay(Calendar working, CronEntry dayOfMonth, CronEntry dayOfWeek) throws MessageFormatException {

         int currentDayOfWeek = working.get(Calendar.DAY_OF_WEEK) - 1;
         int currentDayOfMonth = working.get(Calendar.DAY_OF_MONTH);

         // Simplest case, both are unrestricted or both match today otherwise
         // result must be the closer of the two if both are set, or the next
         // match to the one that is.
         if (!isCurrent(dayOfWeek, currentDayOfWeek) || !isCurrent(dayOfMonth, currentDayOfMonth)) {

             int nextWeekDay = Integer.MAX_VALUE;
             int nextCalendarDay = Integer.MAX_VALUE;

             if (!isCurrent(dayOfWeek, currentDayOfWeek)) {
                 nextWeekDay = getNext(dayOfWeek, currentDayOfWeek);
             }

             if (!isCurrent(dayOfMonth, currentDayOfMonth)) {
                 nextCalendarDay = getNext(dayOfMonth, currentDayOfMonth);
             }

             if (nextWeekDay < nextCalendarDay) {
                 working.add(Calendar.DAY_OF_WEEK, nextWeekDay);
             } else {
                 working.add(Calendar.DAY_OF_MONTH, nextCalendarDay);
             }

             // Since the day changed, we restart the clock at the start of the day
             // so that the next time will either be at 12am + value of hours and
             // minutes pattern.
             resetToStartOfDay(working, working.get(Calendar.DAY_OF_MONTH));

             return working.getTimeInMillis();
         }

         return 0L;
     }

     public static void validate(final String cronEntry) throws MessageFormatException {
         List<String> list = tokenize(cronEntry);
         List<CronEntry> entries = buildCronEntries(list);
         for (CronEntry e : entries) {
             validate(e);
         }
     }

     static void validate(final CronEntry entry) throws MessageFormatException {
         List<Integer> list = entry.currentWhen;
         if (list.isEmpty() || list.get(0).intValue() < entry.start || list.get(list.size() - 1).intValue() > entry.end) {
             throw new MessageFormatException("Invalid token: " + entry);
         }
     }

     static int getNext(final CronEntry entry, final int current) throws MessageFormatException {
         int result = 0;

         if (entry.currentWhen == null) {
             entry.currentWhen = calculateValues(entry);
         }

         List<Integer> list = entry.currentWhen;
         int next = -1;
         for (Integer i : list) {
             if (i.intValue() > current) {
                 next = i.intValue();
                 break;
             }
         }
         if (next != -1) {
             result = next - current;
         } else {
             int first = list.get(0).intValue();
             result = entry.end + first - entry.start - current;

             // Account for difference of one vs zero based indices.
             if (entry.name.equals("DayOfWeek") || entry.name.equals("Month")) {
                 result++;
             }
         }

         return result;
     }

     static boolean isCurrent(final CronEntry entry, final int current) throws MessageFormatException {
         boolean result = entry.currentWhen.contains(new Integer(current));
         return result;
     }

     protected static void resetToStartOfDay(Calendar target, int day) {
         target.set(Calendar.DAY_OF_MONTH, day);
         target.set(Calendar.HOUR_OF_DAY, 0);
         target.set(Calendar.MINUTE, 0);
         target.set(Calendar.SECOND, 0);
     }

     static List<String> tokenize(String cron) throws IllegalArgumentException {
         StringTokenizer tokenize = new StringTokenizer(cron);
         List<String> result = new ArrayList<String>();
         while (tokenize.hasMoreTokens()) {
             result.add(tokenize.nextToken());
         }
         if (result.size() != NUMBER_TOKENS) {
             throw new IllegalArgumentException("Not a valid cron entry - wrong number of tokens(" + result.size() + "): " + cron);
         }
         return result;
     }

     protected static List<Integer> calculateValues(final CronEntry entry) {
         List<Integer> result = new ArrayList<Integer>();
         if (isAll(entry.token)) {
             for (int i = entry.start; i <= entry.end; i++) {
                 result.add(i);
             }
         } else if (isAStep(entry.token)) {
             int denominator = getDenominator(entry.token);
             String numerator = getNumerator(entry.token);
             CronEntry ce = new CronEntry(entry.name, numerator, entry.start, entry.end);
             List<Integer> list = calculateValues(ce);
             for (Integer i : list) {
                 if (i.intValue() % denominator == 0) {
                     result.add(i);
                 }
             }
         } else if (isAList(entry.token)) {
             StringTokenizer tokenizer = new StringTokenizer(entry.token, ",");
             while (tokenizer.hasMoreTokens()) {
                 String str = tokenizer.nextToken();
                 CronEntry ce = new CronEntry(entry.name, str, entry.start, entry.end);
                 List<Integer> list = calculateValues(ce);
                 result.addAll(list);
             }
         } else if (isARange(entry.token)) {
             int index = entry.token.indexOf('-');
             int first = Integer.parseInt(entry.token.substring(0, index));
             int last = Integer.parseInt(entry.token.substring(index + 1));
             for (int i = first; i <= last; i++) {
                 result.add(i);
             }
         } else {
             int value = Integer.parseInt(entry.token);
             result.add(value);
         }
         Collections.sort(result);
         return result;
     }

     protected static boolean isARange(String token) {
         return token != null && token.indexOf('-') >= 0;
     }

     protected static boolean isAStep(String token) {
         return token != null && token.indexOf('/') >= 0;
     }

     protected static boolean isAList(String token) {
         return token != null && token.indexOf(',') >= 0;
     }

     protected static boolean isAll(String token) {
         return token != null && token.length() == 1 && (token.charAt(0) == '*' || token.charAt(0) == '?');
     }

     protected static int getDenominator(final String token) {
         int result = 0;
         int index = token.indexOf('/');
         String str = token.substring(index + 1);
         result = Integer.parseInt(str);
         return result;
     }

     protected static String getNumerator(final String token) {
         int index = token.indexOf('/');
         String str = token.substring(0, index);
         return str;
     }

     static List<CronEntry> buildCronEntries(List<String> tokens) {

         List<CronEntry> result = new ArrayList<CronEntry>();

         CronEntry minutes = new CronEntry("Minutes", tokens.get(MINUTES), 0, 60);
         minutes.currentWhen = calculateValues(minutes);
         result.add(minutes);
         CronEntry hours = new CronEntry("Hours", tokens.get(HOURS), 0, 24);
         hours.currentWhen = calculateValues(hours);
         result.add(hours);
         CronEntry dayOfMonth = new CronEntry("DayOfMonth", tokens.get(DAY_OF_MONTH), 1, 31);
         dayOfMonth.currentWhen = calculateValues(dayOfMonth);
         result.add(dayOfMonth);
         CronEntry month = new CronEntry("Month", tokens.get(MONTH), 1, 12);
         month.currentWhen = calculateValues(month);
         result.add(month);
         CronEntry dayOfWeek = new CronEntry("DayOfWeek", tokens.get(DAY_OF_WEEK), 0, 6);
         dayOfWeek.currentWhen = calculateValues(dayOfWeek);
         result.add(dayOfWeek);

         return result;
     }

     static class CronEntry {

         final String name;
         final String token;
         final int start;
         final int end;

         List<Integer> currentWhen;

         CronEntry(String name, String token, int start, int end) {
             this.name = name;
             this.token = token;
             this.start = start;
             this.end = end;
         }

         @Override
         public String toString() {
             return this.name + ":" + token;
         }
     }
 }
	/**
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You under the Apache License, Version 2.0
	* (the "License"); you may not use this file except in compliance with
	* the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	package org.apache.activemq.openwire.utils;

	import java.util.ArrayList;
	import java.util.Calendar;
	import java.util.Collections;
	import java.util.List;
	import java.util.StringTokenizer;

	import javax.jms.MessageFormatException;

	public class CronParser {

	private static final int NUMBER_TOKENS = 5;
	private static final int MINUTES = 0;
	private static final int HOURS = 1;
	private static final int DAY_OF_MONTH = 2;
	private static final int MONTH = 3;
	private static final int DAY_OF_WEEK = 4;

	public static long getNextScheduledTime(final String cronEntry, long currentTime) throws MessageFormatException {

	long result = 0;

	if (cronEntry == null \|\| cronEntry.length() == 0) {
	return result;
	}

	// Handle the once per minute case "* * * * *"
	// starting the next event at the top of the minute.
	if (cronEntry.equals("* * * * *")) {
	result = currentTime + 60 * 1000;
	result = result / 60000 * 60000;
	return result;
	}

	List<String> list = tokenize(cronEntry);
	List<CronEntry> entries = buildCronEntries(list);
	Calendar working = Calendar.getInstance();
	working.setTimeInMillis(currentTime);
	working.set(Calendar.SECOND, 0);

	CronEntry minutes = entries.get(MINUTES);
	CronEntry hours = entries.get(HOURS);
	CronEntry dayOfMonth = entries.get(DAY_OF_MONTH);
	CronEntry month = entries.get(MONTH);
	CronEntry dayOfWeek = entries.get(DAY_OF_WEEK);

	// Start at the top of the next minute, cron is only guaranteed to be
	// run on the minute.
	int timeToNextMinute = 60 - working.get(Calendar.SECOND);
	working.add(Calendar.SECOND, timeToNextMinute);

	// If its already to late in the day this will roll us over to tomorrow
	// so we'll need to check again when done updating month and day.
	int currentMinutes = working.get(Calendar.MINUTE);
	if (!isCurrent(minutes, currentMinutes)) {
	int nextMinutes = getNext(minutes, currentMinutes);
	working.add(Calendar.MINUTE, nextMinutes);
	}

	int currentHours = working.get(Calendar.HOUR_OF_DAY);
	if (!isCurrent(hours, currentHours)) {
	int nextHour = getNext(hours, currentHours);
	working.add(Calendar.HOUR_OF_DAY, nextHour);
	}

	// We can roll into the next month here which might violate the cron setting
	// rules so we check once then recheck again after applying the month settings.
	doUpdateCurrentDay(working, dayOfMonth, dayOfWeek);

	// Start by checking if we are in the right month, if not then calculations
	// need to start from the beginning of the month to ensure that we don't end
	// up on the wrong day. (Can happen when DAY_OF_WEEK is set and current time
	// is ahead of the day of the week to execute on).
	doUpdateCurrentMonth(working, month);

	// Now Check day of week and day of month together since they can be specified
	// together in one entry, if both "day of month" and "day of week" are restricted
	// (not "*"), then either the "day of month" field (3) or the "day of week" field
	// (5) must match the current day or the Calenday must be advanced.
	doUpdateCurrentDay(working, dayOfMonth, dayOfWeek);

	// Now we can chose the correct hour and minute of the day in question.

	currentHours = working.get(Calendar.HOUR_OF_DAY);
	if (!isCurrent(hours, currentHours)) {
	int nextHour = getNext(hours, currentHours);
	working.add(Calendar.HOUR_OF_DAY, nextHour);
	}

	currentMinutes = working.get(Calendar.MINUTE);
	if (!isCurrent(minutes, currentMinutes)) {
	int nextMinutes = getNext(minutes, currentMinutes);
	working.add(Calendar.MINUTE, nextMinutes);
	}

	result = working.getTimeInMillis();

	if (result <= currentTime) {
	throw new ArithmeticException("Unable to compute next scheduled exection time.");
	}

	return result;
	}

	protected static long doUpdateCurrentMonth(Calendar working, CronEntry month) throws MessageFormatException {
	int currentMonth = working.get(Calendar.MONTH) + 1;
	if (!isCurrent(month, currentMonth)) {
	int nextMonth = getNext(month, currentMonth);
	working.add(Calendar.MONTH, nextMonth);

	// Reset to start of month.
	resetToStartOfDay(working, 1);

	return working.getTimeInMillis();
	}

	return 0L;
	}

	protected static long doUpdateCurrentDay(Calendar working, CronEntry dayOfMonth, CronEntry dayOfWeek) throws MessageFormatException {

	int currentDayOfWeek = working.get(Calendar.DAY_OF_WEEK) - 1;
	int currentDayOfMonth = working.get(Calendar.DAY_OF_MONTH);

	// Simplest case, both are unrestricted or both match today otherwise
	// result must be the closer of the two if both are set, or the next
	// match to the one that is.
	if (!isCurrent(dayOfWeek, currentDayOfWeek) \|\| !isCurrent(dayOfMonth, currentDayOfMonth)) {

	int nextWeekDay = Integer.MAX_VALUE;
	int nextCalendarDay = Integer.MAX_VALUE;

	if (!isCurrent(dayOfWeek, currentDayOfWeek)) {
	nextWeekDay = getNext(dayOfWeek, currentDayOfWeek);
	}

	if (!isCurrent(dayOfMonth, currentDayOfMonth)) {
	nextCalendarDay = getNext(dayOfMonth, currentDayOfMonth);
	}

	if (nextWeekDay < nextCalendarDay) {
	working.add(Calendar.DAY_OF_WEEK, nextWeekDay);
	} else {
	working.add(Calendar.DAY_OF_MONTH, nextCalendarDay);
	}

	// Since the day changed, we restart the clock at the start of the day
	// so that the next time will either be at 12am + value of hours and
	// minutes pattern.
	resetToStartOfDay(working, working.get(Calendar.DAY_OF_MONTH));

	return working.getTimeInMillis();
	}

	return 0L;
	}

	public static void validate(final String cronEntry) throws MessageFormatException {
	List<String> list = tokenize(cronEntry);
	List<CronEntry> entries = buildCronEntries(list);
	for (CronEntry e : entries) {
	validate(e);
	}
	}

	static void validate(final CronEntry entry) throws MessageFormatException {
	List<Integer> list = entry.currentWhen;
	if (list.isEmpty() \|\| list.get(0).intValue() < entry.start \|\| list.get(list.size() - 1).intValue() > entry.end) {
	throw new MessageFormatException("Invalid token: " + entry);
	}
	}

	static int getNext(final CronEntry entry, final int current) throws MessageFormatException {
	int result = 0;

	if (entry.currentWhen == null) {
	entry.currentWhen = calculateValues(entry);
	}

	List<Integer> list = entry.currentWhen;
	int next = -1;
	for (Integer i : list) {
	if (i.intValue() > current) {
	next = i.intValue();
	break;
	}
	}
	if (next != -1) {
	result = next - current;
	} else {
	int first = list.get(0).intValue();
	result = entry.end + first - entry.start - current;

	// Account for difference of one vs zero based indices.
	if (entry.name.equals("DayOfWeek") \|\| entry.name.equals("Month")) {
	result++;
	}
	}

	return result;
	}

	static boolean isCurrent(final CronEntry entry, final int current) throws MessageFormatException {
	boolean result = entry.currentWhen.contains(new Integer(current));
	return result;
	}

	protected static void resetToStartOfDay(Calendar target, int day) {
	target.set(Calendar.DAY_OF_MONTH, day);
	target.set(Calendar.HOUR_OF_DAY, 0);
	target.set(Calendar.MINUTE, 0);
	target.set(Calendar.SECOND, 0);
	}

	static List<String> tokenize(String cron) throws IllegalArgumentException {
	StringTokenizer tokenize = new StringTokenizer(cron);
	List<String> result = new ArrayList<String>();
	while (tokenize.hasMoreTokens()) {
	result.add(tokenize.nextToken());
	}
	if (result.size() != NUMBER_TOKENS) {
	throw new IllegalArgumentException("Not a valid cron entry - wrong number of tokens(" + result.size() + "): " + cron);
	}
	return result;
	}

	protected static List<Integer> calculateValues(final CronEntry entry) {
	List<Integer> result = new ArrayList<Integer>();
	if (isAll(entry.token)) {
	for (int i = entry.start; i <= entry.end; i++) {
	result.add(i);
	}
	} else if (isAStep(entry.token)) {
	int denominator = getDenominator(entry.token);
	String numerator = getNumerator(entry.token);
	CronEntry ce = new CronEntry(entry.name, numerator, entry.start, entry.end);
	List<Integer> list = calculateValues(ce);
	for (Integer i : list) {
	if (i.intValue() % denominator == 0) {
	result.add(i);
	}
	}
	} else if (isAList(entry.token)) {
	StringTokenizer tokenizer = new StringTokenizer(entry.token, ",");
	while (tokenizer.hasMoreTokens()) {
	String str = tokenizer.nextToken();
	CronEntry ce = new CronEntry(entry.name, str, entry.start, entry.end);
	List<Integer> list = calculateValues(ce);
	result.addAll(list);
	}
	} else if (isARange(entry.token)) {
	int index = entry.token.indexOf('-');
	int first = Integer.parseInt(entry.token.substring(0, index));
	int last = Integer.parseInt(entry.token.substring(index + 1));
	for (int i = first; i <= last; i++) {
	result.add(i);
	}
	} else {
	int value = Integer.parseInt(entry.token);
	result.add(value);
	}
	Collections.sort(result);
	return result;
	}

	protected static boolean isARange(String token) {
	return token != null && token.indexOf('-') >= 0;
	}

	protected static boolean isAStep(String token) {
	return token != null && token.indexOf('/') >= 0;
	}

	protected static boolean isAList(String token) {
	return token != null && token.indexOf(',') >= 0;
	}

	protected static boolean isAll(String token) {
	return token != null && token.length() == 1 && (token.charAt(0) == '*' \|\| token.charAt(0) == '?');
	}

	protected static int getDenominator(final String token) {
	int result = 0;
	int index = token.indexOf('/');
	String str = token.substring(index + 1);
	result = Integer.parseInt(str);
	return result;
	}

	protected static String getNumerator(final String token) {
	int index = token.indexOf('/');
	String str = token.substring(0, index);
	return str;
	}

	static List<CronEntry> buildCronEntries(List<String> tokens) {

	List<CronEntry> result = new ArrayList<CronEntry>();

	CronEntry minutes = new CronEntry("Minutes", tokens.get(MINUTES), 0, 60);
	minutes.currentWhen = calculateValues(minutes);
	result.add(minutes);
	CronEntry hours = new CronEntry("Hours", tokens.get(HOURS), 0, 24);
	hours.currentWhen = calculateValues(hours);
	result.add(hours);
	CronEntry dayOfMonth = new CronEntry("DayOfMonth", tokens.get(DAY_OF_MONTH), 1, 31);
	dayOfMonth.currentWhen = calculateValues(dayOfMonth);
	result.add(dayOfMonth);
	CronEntry month = new CronEntry("Month", tokens.get(MONTH), 1, 12);
	month.currentWhen = calculateValues(month);
	result.add(month);
	CronEntry dayOfWeek = new CronEntry("DayOfWeek", tokens.get(DAY_OF_WEEK), 0, 6);
	dayOfWeek.currentWhen = calculateValues(dayOfWeek);
	result.add(dayOfWeek);

	return result;
	}

	static class CronEntry {

	final String name;
	final String token;
	final int start;
	final int end;

	List<Integer> currentWhen;

	CronEntry(String name, String token, int start, int end) {
	this.name = name;
	this.token = token;
	this.start = start;
	this.end = end;
	}

	@Override
	public String toString() {
	return this.name + ":" + token;
	}
	}
	}