org.orekit.propagation.events

Class EventState<T extends EventDetector>

java.lang.Object

org.orekit.propagation.events.EventState<T>

Type Parameters:

T - class type for the generic version

All Implemented Interfaces:

Serializable

public class EventState<T extends EventDetector>
extends Object
implements Serializable

This class handles the state for one event detector during integration steps.

This class is heavily based on the class with the same name from the Apache Commons Math library. The changes performed consist in replacing raw types (double and double arrays) with space dynamics types (AbsoluteDate, SpacecraftState).

Each time the propagator proposes a step, the event detector should be checked. This class handles the state of one detector during one propagation step, with references to the state at the end of the preceding step. This information is used to determine if the detector should trigger an event or not during the proposed step (and hence the step should be reduced to ensure the event occurs at a bound rather than inside the step).

Author:

Luc Maisonobe

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
EventState(T detector) Simple constructor.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	evaluateStep(OrekitStepInterpolator interpolator) Evaluate the impact of the proposed step on the event detector.
T	getEventDetector() Get the underlying event detector.
AbsoluteDate	getEventTime() Get the occurrence time of the event triggered in the current step.
void	init(SpacecraftState s0, AbsoluteDate t) Initialize event handler at the start of a propagation.
void	reinitializeBegin(SpacecraftState state0, boolean isForward) Reinitialize the beginning of the step.
SpacecraftState	reset(SpacecraftState oldState) Let the event detector reset the state if it wants.
void	stepAccepted(SpacecraftState state) Acknowledge the fact the step has been accepted by the propagator.
boolean	stop() Check if the propagation should be stopped at the end of the current step.

Methods inherited from class java.lang.Object

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

Constructor Detail

EventState

public EventState(T detector)

Simple constructor.

Parameters:

detector - monitored event detector

Method Detail

getEventDetector

public T getEventDetector()

Get the underlying event detector.

Returns:

underlying event detector

init

public void init(SpacecraftState s0,
        AbsoluteDate t)

Initialize event handler at the start of a propagation.

This method is called once at the start of the propagation. It may be used by the event handler to initialize some internal data if needed.

Parameters:

s0 - initial state

t - target time for the integration

reinitializeBegin

public void reinitializeBegin(SpacecraftState state0,
                     boolean isForward)
                       throws OrekitException

Reinitialize the beginning of the step.

Parameters:

state0 - state value at the beginning of the step

isForward - if true, step will be forward

Throws:

OrekitException - if the event detector value cannot be evaluated at the beginning of the step

evaluateStep

public boolean evaluateStep(OrekitStepInterpolator interpolator)
                     throws OrekitException,
                            TooManyEvaluationsException,
                            NoBracketingException

Evaluate the impact of the proposed step on the event detector.

Parameters:

interpolator - step interpolator for the proposed step

Returns:

true if the event detector triggers an event before the end of the proposed step (this implies the step should be rejected)

Throws:

OrekitException - if the switching function cannot be evaluated

TooManyEvaluationsException - if an event cannot be located

NoBracketingException - if bracketing cannot be performed

getEventTime

public AbsoluteDate getEventTime()

Get the occurrence time of the event triggered in the current step.

Returns:

occurrence time of the event triggered in the current step.

stepAccepted

public void stepAccepted(SpacecraftState state)
                  throws OrekitException

Acknowledge the fact the step has been accepted by the propagator.

Parameters:

state - value of the state vector at the end of the step

Throws:

OrekitException - if the value of the switching function cannot be evaluated

stop

public boolean stop()

Check if the propagation should be stopped at the end of the current step.

Returns:

true if the propagation should be stopped

reset

public SpacecraftState reset(SpacecraftState oldState)
                      throws OrekitException

Let the event detector reset the state if it wants.

Parameters:

oldState - value of the state vector at the beginning of the next step

Returns:

new state (null if no reset is needed)

Throws:

OrekitException - if the state cannot be reset by the event detector