/*
* Copyright (c) 2002-2003 by OpenSymphony
* All rights reserved.
*/
package com.opensymphony.oscache.util;
import java.text.ParseException;
import java.util.*;
import java.util.Calendar;
/**
* Parses cron expressions and determines at what time in the past is the
* most recent match for the supplied expression.
*
* @author <a href="mailto:chris@swebtec.com">Chris Miller</a>
* @author $Author: ltorunski $
* @version $Revision: 340 $
*/
public class FastCronParser {
private static final int NUMBER_OF_CRON_FIELDS = 5;
private static final int MINUTE = 0;
private static final int HOUR = 1;
private static final int DAY_OF_MONTH = 2;
private static final int MONTH = 3;
private static final int DAY_OF_WEEK = 4;
// Lookup tables that hold the min/max/size of each of the above field types.
// These tables are precalculated for performance.
private static final int[] MIN_VALUE = {0, 0, 1, 1, 0};
private static final int[] MAX_VALUE = {59, 23, 31, 12, 6};
/**
* A lookup table holding the number of days in each month (with the obvious exception
* that February requires special handling).
*/
private static final int[] DAYS_IN_MONTH = {
31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
/**
* Holds the raw cron expression that this parser is handling.
*/
private String cronExpression = null;
/**
* This is the main lookup table that holds a parsed cron expression. each long
* represents one of the above field types. Bits in each long value correspond
* to one of the possbile field values - eg, for the minute field, bits 0 -> 59 in
* <code>lookup[MINUTE]</code> map to minutes 0 -> 59 respectively. Bits are set if
* the corresponding value is enabled. So if the minute field in the cron expression
* was <code>"0,2-8,50"</code>, bits 0, 2, 3, 4, 5, 6, 7, 8 and 50 will be set.
* If the cron expression is <code>"*"</code>, the long value is set to
* <code>Long.MAX_VALUE</code>.
*/
private long[] lookup = {
Long.MAX_VALUE, Long.MAX_VALUE, Long.MAX_VALUE, Long.MAX_VALUE,
Long.MAX_VALUE
};
/**
* This is based on the contents of the <code>lookup</code> table. It holds the
* <em>highest</em> valid field value for each field type.
*/
private int[] lookupMax = {-1, -1, -1, -1, -1};
/**
* This is based on the contents of the <code>lookup</code> table. It holds the
* <em>lowest</em> valid field value for each field type.
*/
private int[] lookupMin = {
Integer.MAX_VALUE, Integer.MAX_VALUE, Integer.MAX_VALUE,
Integer.MAX_VALUE, Integer.MAX_VALUE
};
/**
* Creates a FastCronParser that uses a default cron expression of <code>"* * * * *"</cron>.
* This will match any time that is supplied.
*/
public FastCronParser() {
}
/**
* Constructs a new FastCronParser based on the supplied expression.
*
* @throws ParseException if the supplied expression is not a valid cron expression.
*/
public FastCronParser(String cronExpression) throws ParseException {
setCronExpression(cronExpression);
}
/**
* Resets the cron expression to the value supplied.
*
* @param cronExpression the new cron expression.
*
* @throws ParseException if the supplied expression is not a valid cron expression.
*/
public void setCronExpression(String cronExpression) throws ParseException {
if (cronExpression == null) {
throw new IllegalArgumentException("Cron time expression cannot be null");
}
this.cronExpression = cronExpression;
parseExpression(cronExpression);
}
/**
* Retrieves the current cron expression.
*
* @return the current cron expression.
*/
public String getCronExpression() {
return this.cronExpression;
}
/**
* Determines whether this cron expression matches a date/time that is more recent
* than the one supplied.
*
* @param time The time to compare the cron expression against.
*
* @return <code>true</code> if the cron expression matches a time that is closer
* to the current time than the supplied time is, <code>false</code> otherwise.
*/
public boolean hasMoreRecentMatch(long time) {
return time < getTimeBefore(System.currentTimeMillis());
}
/**
* Find the most recent time that matches this cron expression. This time will
* always be in the past, ie a lower value than the supplied time.
*
* @param time The time (in milliseconds) that we're using as our upper bound.
*
* @return The time (in milliseconds) when this cron event last occurred.
*/
public long getTimeBefore(long time) {
// It would be nice to get rid of the Calendar class for speed, but it's a lot of work...
// We create this
Calendar cal = new GregorianCalendar();
cal.setTimeInMillis(time);
int minute = cal.get(Calendar.MINUTE);
int hour = cal.get(Calendar.HOUR_OF_DAY);
int dayOfMonth = cal.get(Calendar.DAY_OF_MONTH);
int month = cal.get(Calendar.MONTH) + 1; // Calendar is 0-based for this field, and we are 1-based
int year = cal.get(Calendar.YEAR);
long validMinutes = lookup[MINUTE];
long validHours = lookup[HOUR];
long validDaysOfMonth = lookup[DAY_OF_MONTH];
long validMonths = lookup[MONTH];
long validDaysOfWeek = lookup[DAY_OF_WEEK];
// Find out if we have a Day of Week or Day of Month field
boolean haveDOM = validDaysOfMonth != Long.MAX_VALUE;
boolean haveDOW = validDaysOfWeek != Long.MAX_VALUE;
boolean skippedNonLeapYear = false;
while (true) {
boolean retry = false;
// Clean up the month if it was wrapped in a previous iteration
if (month < 1) {
month += 12;
year--;
}
// get month...................................................
boolean found = false;
if (validMonths != Long.MAX_VALUE) {
for (int i = month + 11; i > (month - 1); i--) {
int testMonth = (i % 12) + 1;
// Check if the month is valid
if (((1L << (testMonth - 1)) & validMonths) != 0) {
if ((testMonth > month) || skippedNonLeapYear) {
year--;
}
// Check there are enough days in this month (catches non leap-years trying to match the 29th Feb)
int numDays = numberOfDaysInMonth(testMonth, year);
if (!haveDOM || (numDays >= lookupMin[DAY_OF_MONTH])) {
if ((month != testMonth) || skippedNonLeapYear) {
// New DOM = min(maxDOM, prevDays); ie, the highest valid value
dayOfMonth = (numDays <= lookupMax[DAY_OF_MONTH]) ? numDays : lookupMax[DAY_OF_MONTH];
hour = lookupMax[HOUR];
minute = lookupMax[MINUTE];
month = testMonth;
}
found = true;
break;
}
}
}
skippedNonLeapYear = false;
if (!found) {
// The only time we drop out here is when we're searching for the 29th of February and no other date!
skippedNonLeapYear = true;
continue;
}
}
// Clean up if the dayOfMonth was wrapped. This takes leap years into account.
if (dayOfMonth < 1) {
month--;
dayOfMonth += numberOfDaysInMonth(month, year);
hour = lookupMax[HOUR];
continue;
}
// get day...................................................
if (haveDOM && !haveDOW) { // get day using just the DAY_OF_MONTH token
int daysInThisMonth = numberOfDaysInMonth(month, year);
int daysInPreviousMonth = numberOfDaysInMonth(month - 1, year);
// Find the highest valid day that is below the current day
for (int i = dayOfMonth + 30; i > (dayOfMonth - 1); i--) {
int testDayOfMonth = (i % 31) + 1;
// Skip over any days that don't actually exist (eg 31st April)
if ((testDayOfMonth <= dayOfMonth) && (testDayOfMonth > daysInThisMonth)) {
continue;
}
if ((testDayOfMonth > dayOfMonth) && (testDayOfMonth > daysInPreviousMonth)) {
continue;
}
if (((1L << (testDayOfMonth - 1)) & validDaysOfMonth) != 0) {
if (testDayOfMonth > dayOfMonth) {
// We've found a valid day, but we had to move back a month
month--;
retry = true;
}
if (dayOfMonth != testDayOfMonth) {
hour = lookupMax[HOUR];
minute = lookupMax[MINUTE];
}
dayOfMonth = testDayOfMonth;
break;
}
}
if (retry) {
continue;
}
} else if (haveDOW && !haveDOM) { // get day using just the DAY_OF_WEEK token
int daysLost = 0;
int currentDOW = dayOfWeek(dayOfMonth, month, year);
for (int i = currentDOW + 7; i > currentDOW; i--) {
int testDOW = i % 7;
if (((1L << testDOW) & validDaysOfWeek) != 0) {
dayOfMonth -= daysLost;
if (dayOfMonth < 1) {
// We've wrapped back a month
month--;
dayOfMonth += numberOfDaysInMonth(month, year);
retry = true;
}
if (currentDOW != testDOW) {
hour = lookupMax[HOUR];
minute = lookupMax[MINUTE];
}
break;
}
daysLost++;
}
if (retry) {
continue;
}
}
// Clean up if the hour has been wrapped
if (hour < 0) {
hour += 24;
dayOfMonth--;
continue;
}
// get hour...................................................
if (validHours != Long.MAX_VALUE) {
// Find the highest valid hour that is below the current hour
for (int i = hour + 24; i > hour; i--) {
int testHour = i % 24;
if (((1L << testHour) & validHours) != 0) {
if (testHour > hour) {
// We've found an hour, but we had to move back a day
dayOfMonth--;
retry = true;
}
if (hour != testHour) {
minute = lookupMax[MINUTE];
}
hour = testHour;
break;
}
}
if (retry) {
continue;
}
}
// get minute.................................................
if (validMinutes != Long.MAX_VALUE) {
// Find the highest valid minute that is below the current minute
for (int i = minute + 60; i > minute; i--) {
int testMinute = i % 60;
if (((1L << testMinute) & validMinutes) != 0) {
if (testMinute > minute) {
// We've found a minute, but we had to move back an hour
hour--;
retry = true;
}
minute = testMinute;
break;
}
}
if (retry) {
continue;
}
}
break;
}
// OK, all done. Return the adjusted time value (adjusting this is faster than creating a new Calendar object)
cal.set(Calendar.YEAR, year);
cal.set(Calendar.MONTH, month - 1); // Calendar is 0-based for this field, and we are 1-based
cal.set(Calendar.DAY_OF_MONTH, dayOfMonth);
cal.set(Calendar.HOUR_OF_DAY, hour);
cal.set(Calendar.MINUTE, minute);
cal.set(Calendar.SECOND, 0);
cal.set(Calendar.MILLISECOND, 0);
return cal.getTime().getTime();
}
/**
* Takes a cron expression as an input parameter, and extracts from it the
* relevant minutes/hours/days/months that the expression matches.
*
* @param expression A valid cron expression.
* @throws ParseException If the supplied expression could not be parsed.
*/
private void parseExpression(String expression) throws ParseException {
try {
// Reset all the lookup data
for (int i = 0; i < lookup.length; lookup[i++] = 0) {
lookupMin[i] = Integer.MAX_VALUE;
lookupMax[i] = -1;
}
// Create some character arrays to hold the extracted field values
char[][] token = new char[NUMBER_OF_CRON_FIELDS][];
// Extract the supplied expression into another character array
// for speed
int length = expression.length();
char[] expr = new char[length];
expression.getChars(0, length, expr, 0);
int field = 0;
int startIndex = 0;
boolean inWhitespace = true;
// Extract the various cron fields from the expression
for (int i = 0; (i < length) && (field < NUMBER_OF_CRON_FIELDS);
i++) {
boolean haveChar = (expr[i] != ' ') && (expr[i] != '\t');
if (haveChar) {
// We have a text character of some sort
if (inWhitespace) {
startIndex = i; // Remember the start of this token
inWhitespace = false;
}
}
if (i == (length - 1)) { // Adjustment for when we reach the end of the expression
i++;
}
if (!(haveChar || inWhitespace) || (i == length)) {
// We've reached the end of a token. Copy it into a new char array
token[field] = new char[i - startIndex];
System.arraycopy(expr, startIndex, token[field], 0, i - startIndex);
inWhitespace = true;
field++;
}
}
if (field < NUMBER_OF_CRON_FIELDS) {
throw new ParseException("Unexpected end of expression while parsing \"" + expression + "\". Cron expressions require 5 separate fields.", length);
}
// OK, we've broken the string up into the 5 cron fields, now lets add
// each field to their lookup table.
for (field = 0; field < NUMBER_OF_CRON_FIELDS; field++) {
startIndex = 0;
boolean inDelimiter = true;
// We add each comma-delimited element seperately.
int elementLength = token[field].length;
for (int i = 0; i < elementLength; i++) {
boolean haveElement = token[field][i] != ',';
if (haveElement) {
// We have a character from an element in the token
if (inDelimiter) {
startIndex = i;
inDelimiter = false;
}
}
if (i == (elementLength - 1)) { // Adjustment for when we reach the end of the token
i++;
}
if (!(haveElement || inDelimiter) || (i == elementLength)) {
// We've reached the end of an element. Copy it into a new char array
char[] element = new char[i - startIndex];
System.arraycopy(token[field], startIndex, element, 0, i - startIndex);
// Add the element to our datastructure.
storeExpressionValues(element, field);
inDelimiter = true;
}
}
if (lookup[field] == 0) {
throw new ParseException("Token " + new String(token[field]) + " contains no valid entries for this field.", 0);
}
}
// Remove any months that will never be valid
switch (lookupMin[DAY_OF_MONTH]) {
case 31:
lookup[MONTH] &= (0xFFF - 0x528); // Binary 010100101000 - the months that have 30 days
case 30:
lookup[MONTH] &= (0xFFF - 0x2); // Binary 000000000010 - February
if (lookup[MONTH] == 0) {
throw new ParseException("The cron expression \"" + expression + "\" will never match any months - the day of month field is out of range.", 0);
}
}
// Check that we don't have both a day of month and a day of week field.
if ((lookup[DAY_OF_MONTH] != Long.MAX_VALUE) && (lookup[DAY_OF_WEEK] != Long.MAX_VALUE)) {
throw new ParseException("The cron expression \"" + expression + "\" is invalid. Having both a day-of-month and day-of-week field is not supported.", 0);
}
} catch (Exception e) {
if (e instanceof ParseException) {
throw (ParseException) e;
} else {
throw new ParseException("Illegal cron expression format (" + e.toString() + ")", 0);
}
}
}
/**
* Stores the values for the supplied cron element into the specified field.
*
* @param element The cron element to store. A cron element is a single component
* of a cron expression. For example, the complete set of elements for the cron expression
* <code>30 0,6,12,18 * * *</code> would be <code>{"30", "0", "6", "12", "18", "*", "*", "*"}</code>.
* @param field The field that this expression belongs to. Valid values are {@link #MINUTE},
* {@link #HOUR}, {@link #DAY_OF_MONTH}, {@link #MONTH} and {@link #DAY_OF_WEEK}.
*
* @throws ParseException if there was a problem parsing the supplied element.
*/
private void storeExpressionValues(char[] element, int field) throws ParseException {
int i = 0;
int start = -99;
int end = -99;
int interval = -1;
boolean wantValue = true;
boolean haveInterval = false;
while ((interval < 0) && (i < element.length)) {
char ch = element[i++];
// Handle the wildcard character - it can only ever occur at the start of an element
if ((i == 1) && (ch == '*')) {
// Handle the special case where we have '*' and nothing else
if (i >= element.length) {
addToLookup(-1, -1, field, 1);
return;
}
start = -1;
end = -1;
wantValue = false;
continue;
}
if (wantValue) {
// Handle any numbers
if ((ch >= '0') && (ch <= '9')) {
ValueSet vs = getValue(ch - '0', element, i);
if (start == -99) {
start = vs.value;
} else if (!haveInterval) {
end = vs.value;
} else {
if (end == -99) {
end = MAX_VALUE[field];
}
interval = vs.value;
}
i = vs.pos;
wantValue = false;
continue;
}
if (!haveInterval && (end == -99)) {
// Handle any months that have been suplied as words
if (field == MONTH) {
if (start == -99) {
start = getMonthVal(ch, element, i++);
} else {
end = getMonthVal(ch, element, i++);
}
wantValue = false;
// Skip past the rest of the month name
while (++i < element.length) {
int c = element[i] | 0x20;
if ((c < 'a') || (c > 'z')) {
break;
}
}
continue;
} else if (field == DAY_OF_WEEK) {
if (start == -99) {
start = getDayOfWeekVal(ch, element, i++);
} else {
end = getDayOfWeekVal(ch, element, i++);
}
wantValue = false;
// Skip past the rest of the day name
while (++i < element.length) {
int c = element[i] | 0x20;
if ((c < 'a') || (c > 'z')) {
break;
}
}
continue;
}
}
} else {
// Handle the range character. A range character is only valid if we have a start but no end value
if ((ch == '-') && (start != -99) && (end == -99)) {
wantValue = true;
continue;
}
// Handle an interval. An interval is valid as long as we have a start value
if ((ch == '/') && (start != -99)) {
wantValue = true;
haveInterval = true;
continue;
}
}
throw makeParseException("Invalid character encountered while parsing element", element, i);
}
if (element.length > i) {
throw makeParseException("Extraneous characters found while parsing element", element, i);
}
if (end == -99) {
end = start;
}
if (interval < 0) {
interval = 1;
}
addToLookup(start, end, field, interval);
}
/**
* Extracts a numerical value from inside a character array.
*
* @param value The value of the first character
* @param element The character array we're extracting the value from
* @param i The index into the array of the next character to process
*
* @return the new index and the extracted value
*/
private ValueSet getValue(int value, char[] element, int i) {
ValueSet result = new ValueSet();
result.value = value;
if (i >= element.length) {
result.pos = i;
return result;
}
char ch = element[i];
while ((ch >= '0') && (ch <= '9')) {
result.value = (result.value * 10) + (ch - '0');
if (++i >= element.length) {
break;
}
ch = element[i];
}
result.pos = i;
return result;
}
/**
* Adds a group of valid values to the lookup table for the specified field. This method
* handles ranges that increase in arbitrary step sizes. It is also possible to add a single
* value by specifying a range with the same start and end values.
*
* @param start The starting value for the range. Supplying a value that is less than zero
* will cause the minimum allowable value for the specified field to be used as the start value.
* @param end The maximum value that can be added (ie the upper bound). If the step size is
* greater than one, this maximum value may not necessarily end up being added. Supplying a
* value that is less than zero will cause the maximum allowable value for the specified field
* to be used as the upper bound.
* @param field The field that the values should be added to.
* @param interval Specifies the step size for the range. Any values less than one will be
* treated as a single step interval.
*/
private void addToLookup(int start, int end, int field, int interval) throws ParseException {
// deal with the supplied range
if (start == end) {
if (start < 0) {
// We're setting the entire range of values
start = lookupMin[field] = MIN_VALUE[field];
end = lookupMax[field] = MAX_VALUE[field];
if (interval <= 1) {
lookup[field] = Long.MAX_VALUE;
return;
}
} else {
// We're only setting a single value - check that it is in range
if (start < MIN_VALUE[field]) {
throw new ParseException("Value " + start + " in field " + field + " is lower than the minimum allowable value for this field (min=" + MIN_VALUE[field] + ")", 0);
} else if (start > MAX_VALUE[field]) {
throw new ParseException("Value " + start + " in field " + field + " is higher than the maximum allowable value for this field (max=" + MAX_VALUE[field] + ")", 0);
}
}
} else {
// For ranges, if the start is bigger than the end value then swap them over
if (start > end) {
end ^= start;
start ^= end;
end ^= start;
}
if (start < 0) {
start = MIN_VALUE[field];
} else if (start < MIN_VALUE[field]) {
throw new ParseException("Value " + start + " in field " + field + " is lower than the minimum allowable value for this field (min=" + MIN_VALUE[field] + ")", 0);
}
if (end < 0) {
end = MAX_VALUE[field];
} else if (end > MAX_VALUE[field]) {
throw new ParseException("Value " + end + " in field " + field + " is higher than the maximum allowable value for this field (max=" + MAX_VALUE[field] + ")", 0);
}
}
if (interval < 1) {
interval = 1;
}
int i = start - MIN_VALUE[field];
// Populate the lookup table by setting all the bits corresponding to the valid field values
for (i = start - MIN_VALUE[field]; i <= (end - MIN_VALUE[field]);
i += interval) {
lookup[field] |= (1L << i);
}
// Make sure we remember the minimum value set so far
// Keep track of the highest and lowest values that have been added to this field so far
if (lookupMin[field] > start) {
lookupMin[field] = start;
}
i += (MIN_VALUE[field] - interval);
if (lookupMax[field] < i) {
lookupMax[field] = i;
}
}
/**
* Indicates if a year is a leap year or not.
*
* @param year The year to check
*
* @return <code>true</code> if the year is a leap year, <code>false</code> otherwise.
*/
private boolean isLeapYear(int year) {
return (((year % 4) == 0) && ((year % 100) != 0)) || ((year % 400) == 0);
}
/**
* Calculate the day of the week. Sunday = 0, Monday = 1, ... , Saturday = 6. The formula
* used is an optimized version of Zeller's Congruence.
*
* @param day The day of the month (1-31)
* @param month The month (1 - 12)
* @param year The year
* @return
*/
private int dayOfWeek(int day, int month, int year) {
day += ((month < 3) ? year-- : (year - 2));
return ((((23 * month) / 9) + day + 4 + (year / 4)) - (year / 100) + (year / 400)) % 7;
}
/**
* Retrieves the number of days in the supplied month, taking into account leap years.
* If the month value is outside the range <code>MIN_VALUE[MONTH] - MAX_VALUE[MONTH]</code>
* then the year will be adjusted accordingly and the correct number of days will still
* be returned.
*
* @param month The month of interest.
* @param year The year we are checking.
*
* @return The number of days in the month.
*/
private int numberOfDaysInMonth(int month, int year) {
while (month < 1) {
month += 12;
year--;
}
while (month > 12) {
month -= 12;
year++;
}
if (month == 2) {
return isLeapYear(year) ? 29 : 28;
} else {
return DAYS_IN_MONTH[month - 1];
}
}
/**
* Quickly retrieves the day of week value (Sun = 0, ... Sat = 6) that corresponds to the
* day name that is specified in the character array. Only the first 3 characters are taken
* into account; the rest are ignored.
*
* @param element The character array
* @param i The index to start looking at
* @return The day of week value
*/
private int getDayOfWeekVal(char ch1, char[] element, int i) throws ParseException {
if ((i + 1) >= element.length) {
throw makeParseException("Unexpected end of element encountered while parsing a day name", element, i);
}
int ch2 = element[i] | 0x20;
int ch3 = element[i + 1] | 0x20;
switch (ch1 | 0x20) {
case 's': // Sunday, Saturday
if ((ch2 == 'u') && (ch3 == 'n')) {
return 0;
}
if ((ch2 == 'a') && (ch3 == 't')) {
return 6;
}
break;
case 'm': // Monday
if ((ch2 == 'o') && (ch3 == 'n')) {
return 1;
}
break;
case 't': // Tuesday, Thursday
if ((ch2 == 'u') && (ch3 == 'e')) {
return 2;
}
if ((ch2 == 'h') && (ch3 == 'u')) {
return 4;
}
break;
case 'w': // Wednesday
if ((ch2 == 'e') && (ch3 == 'd')) {
return 3;
}
break;
case 'f': // Friday
if ((ch2 == 'r') && (ch3 == 'i')) {
return 5;
}
break;
}
throw makeParseException("Unexpected character while parsing a day name", element, i - 1);
}
/**
* Quickly retrieves the month value (Jan = 1, ..., Dec = 12) that corresponds to the month
* name that is specified in the character array. Only the first 3 characters are taken
* into account; the rest are ignored.
*
* @param element The character array
* @param i The index to start looking at
* @return The month value
*/
private int getMonthVal(char ch1, char[] element, int i) throws ParseException {
if ((i + 1) >= element.length) {
throw makeParseException("Unexpected end of element encountered while parsing a month name", element, i);
}
int ch2 = element[i] | 0x20;
int ch3 = element[i + 1] | 0x20;
switch (ch1 | 0x20) {
case 'j': // January, June, July
if ((ch2 == 'a') && (ch3 == 'n')) {
return 1;
}
if (ch2 == 'u') {
if (ch3 == 'n') {
return 6;
}
if (ch3 == 'l') {
return 7;
}
}
break;
case 'f': // February
if ((ch2 == 'e') && (ch3 == 'b')) {
return 2;
}
break;
case 'm': // March, May
if (ch2 == 'a') {
if (ch3 == 'r') {
return 3;
}
if (ch3 == 'y') {
return 5;
}
}
break;
case 'a': // April, August
if ((ch2 == 'p') && (ch3 == 'r')) {
return 4;
}
if ((ch2 == 'u') && (ch3 == 'g')) {
return 8;
}
break;
case 's': // September
if ((ch2 == 'e') && (ch3 == 'p')) {
return 9;
}
break;
case 'o': // October
if ((ch2 == 'c') && (ch3 == 't')) {
return 10;
}
break;
case 'n': // November
if ((ch2 == 'o') && (ch3 == 'v')) {
return 11;
}
break;
case 'd': // December
if ((ch2 == 'e') && (ch3 == 'c')) {
return 12;
}
break;
}
throw makeParseException("Unexpected character while parsing a month name", element, i - 1);
}
/**
* Recreates the original human-readable cron expression based on the internal
* datastructure values.
*
* @return A cron expression that corresponds to the current state of the
* internal data structure.
*/
public String getExpressionSummary() {
StringBuffer buf = new StringBuffer();
buf.append(getExpressionSetSummary(MINUTE)).append(' ');
buf.append(getExpressionSetSummary(HOUR)).append(' ');
buf.append(getExpressionSetSummary(DAY_OF_MONTH)).append(' ');
buf.append(getExpressionSetSummary(MONTH)).append(' ');
buf.append(getExpressionSetSummary(DAY_OF_WEEK));
return buf.toString();
}
/**
* <p>Converts the internal datastructure that holds a particular cron field into
* a human-readable list of values of the field's contents. For example, if the
* <code>DAY_OF_WEEK</code> field was submitted that had Sunday and Monday specified,
* the string <code>0,1</code> would be returned.</p>
*
* <p>If the field contains all possible values, <code>*</code> will be returned.
*
* @param field The field.
*
* @return A human-readable string representation of the field's contents.
*/
private String getExpressionSetSummary(int field) {
if (lookup[field] == Long.MAX_VALUE) {
return "*";
}
StringBuffer buf = new StringBuffer();
boolean first = true;
for (int i = MIN_VALUE[field]; i <= MAX_VALUE[field]; i++) {
if ((lookup[field] & (1L << (i - MIN_VALUE[field]))) != 0) {
if (!first) {
buf.append(",");
} else {
first = false;
}
buf.append(String.valueOf(i));
}
}
return buf.toString();
}
/**
* Makes a <code>ParseException</code>. The exception message is constructed by
* taking the given message parameter and appending the supplied character data
* to the end of it. for example, if <code>msg == "Invalid character
* encountered"</code> and <code>data == {'A','g','u','s','t'}</code>, the resultant
* error message would be <code>"Invalid character encountered [Agust]"</code>.
*
* @param msg The error message
* @param data The data that the message
* @param offset The offset into the data where the error was encountered.
*
* @return a newly created <code>ParseException</code> object.
*/
private ParseException makeParseException(String msg, char[] data, int offset) {
char[] buf = new char[msg.length() + data.length + 3];
int msgLen = msg.length();
System.arraycopy(msg.toCharArray(), 0, buf, 0, msgLen);
buf[msgLen] = ' ';
buf[msgLen + 1] = '[';
System.arraycopy(data, 0, buf, msgLen + 2, data.length);
buf[buf.length - 1] = ']';
return new ParseException(new String(buf), offset);
}
}
class ValueSet {
public int pos;
public int value;
}
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