com.espertech.esper.schedule

Class ScheduleComputeHelper

java.lang.Object

com.espertech.esper.schedule.ScheduleComputeHelper

public final class ScheduleComputeHelper
extends Object

For a crontab-like schedule, this class computes the next occurance given a start time and a specification of what the schedule looks like. The resolution at which this works is at the second level. The next occurance is always at least 1 second ahead. The class implements an algorithm that starts at the highest precision (seconds) and continues to the lowest precicion (month). For each precision level the algorithm looks at the list of valid values and finds a value for each that is equal to or greater then the valid values supplied. If no equal or greater value was supplied, it will reset all higher precision elements to its minimum value.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ScheduleComputeHelper.DateCheckerMonthWeekday

Constructor Summary

Constructors

Constructor and Description
ScheduleComputeHelper()

Method Summary

Modifier and Type	Method and Description
static long	computeDeltaNextOccurance(ScheduleSpec spec, long afterTimeInMillis, TimeZone timeZone, TimeAbacus timeAbacus) Computes the next lowest date in milliseconds based on a specification and the from-time passed in and returns the delta from the current time.
static long	computeNextOccurance(ScheduleSpec spec, long afterTimeInMillis, TimeZone timeZone, TimeAbacus timeAbacus) Computes the next lowest date in milliseconds based on a specification and the from-time passed in.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ScheduleComputeHelper

public ScheduleComputeHelper()

Method Detail

computeNextOccurance

public static long computeNextOccurance(ScheduleSpec spec,
                                        long afterTimeInMillis,
                                        TimeZone timeZone,
                                        TimeAbacus timeAbacus)

Computes the next lowest date in milliseconds based on a specification and the from-time passed in.

Parameters:

spec - defines the schedule

afterTimeInMillis - defines the start time

timeZone - time zone

timeAbacus - time abacus

Returns:

a long date millisecond value for the next schedule occurance matching the spec

computeDeltaNextOccurance

public static long computeDeltaNextOccurance(ScheduleSpec spec,
                                             long afterTimeInMillis,
                                             TimeZone timeZone,
                                             TimeAbacus timeAbacus)

Computes the next lowest date in milliseconds based on a specification and the from-time passed in and returns the delta from the current time.

Parameters:

spec - defines the schedule

afterTimeInMillis - defines the start time

timeZone - time zone

timeAbacus - time abacus

Returns:

a long millisecond value representing the delta between current time and the next schedule occurance matching the spec