agi.foundation.propagators

(agi.foundation.models-2025r1.jar)

Class TwoBodyStoppablePropagator

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.propagators.StoppablePropagatorDefinition

agi.foundation.propagators.SinglePointStoppablePropagatorDefinition

agi.foundation.propagators.TwoBodyStoppablePropagator

All Implemented Interfaces:

ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable

public class TwoBodyStoppablePropagator
extends SinglePointStoppablePropagatorDefinition

A StoppablePropagator that propagates an orbit using a simple two-body model.

Constructor Summary

Constructors

Modifier	Constructor and Description
	TwoBodyStoppablePropagator() Initialize a new instance.
	TwoBodyStoppablePropagator(double gravitationalParameter, String propagationPointIdentification, ReferenceFrame propagationFrame, Duration step) Initializes a new instance.
protected	TwoBodyStoppablePropagator(TwoBodyStoppablePropagator existingInstance, CopyContext context) Initializes a new instance as a copy of an existing instance.

Method Summary

Modifier and Type	Method and Description
protected boolean	checkForSameDefinition(SinglePointStoppablePropagatorDefinition other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(TwoBodyStoppablePropagator other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
Object	clone(CopyContext context) Clones this object using the specified context.
protected int	computeCurrentDefinitionHashCode() Computes a hash code based on the current properties of this object.
protected SinglePointStoppablePropagator	createPropagator(EvaluatorGroup group, List<StateElementAdapterDefinition> previousAdapters) Creates and initialize the actual SinglePointStoppablePropagator.
double	getGravitationalParameter() Gets the gravitational parameter of the central body that the propagated element is around.
void	setGravitationalParameter(double value) Sets the gravitational parameter of the central body that the propagated element is around.

Methods inherited from class agi.foundation.propagators.SinglePointStoppablePropagatorDefinition

checkForSameDefinition, enumerateDependencies, getAutomaticallyAddEndOfAvailabilityStoppingConditions, getInitialDate, getInitialMotion, getOrder, getPropagationFrame, getPropagationPoint, getPropagationPointIdentification, getSinglePointPropagator, getSinglePointPropagator, getStep, getStoppablePropagator, setAutomaticallyAddEndOfAvailabilityStoppingConditions, setInitialDate, setInitialMotion, setOrder, setPropagationFrame, setPropagationPointIdentification, setStep

Methods inherited from class agi.foundation.propagators.StoppablePropagatorDefinition

addAnyConditionSatisfied, checkForSameDefinition, containsAdapter, freezeAggregatedObjects, getAdapter, getAllAdapters, getDirection, getStoppablePropagator, getStoppablePropagator, getStoppingConditions, getTimeTolerance, onAnyConditionSatisfied, removeAdapter, removeAnyConditionSatisfied, setAdapter, setTimeTolerance

Methods inherited from class agi.foundation.infrastructure.DefinitionalObject

areSameDefinition, areSameDefinition, areSameDefinition, areSameDefinition, areSameDefinition, collectionItemsAreSameDefinition, collectionItemsAreSameDefinition, collectionItemsAreSameDefinition, dictionaryItemsAreSameDefinition, freeze, getCollectionHashCode, getCollectionHashCode, getCollectionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDefinitionHashCode, getDictionaryHashCode, getIsFrozen, isSameDefinition, throwIfFrozen

Methods inherited from class java.lang.Object

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

Constructor Detail

TwoBodyStoppablePropagator

public TwoBodyStoppablePropagator()

Initialize a new instance.

TwoBodyStoppablePropagator

public TwoBodyStoppablePropagator(double gravitationalParameter,
                                  String propagationPointIdentification,
                                  ReferenceFrame propagationFrame,
                                  @Nonnull
                                  Duration step)

Initializes a new instance. StoppingConditions must still be added before StoppablePropagatorDefinition.getStoppablePropagator(EvaluatorGroup) can be called on this.

Parameters:

gravitationalParameter - The gravitational parameter of the central body that the propagated element is around.

propagationPointIdentification - The name to identify the motion getting propagated in the returned states.

propagationFrame - The ReferenceFrame that the returned data will be in. This should not be a fixed frame.

step - The default step size for this propagator.

TwoBodyStoppablePropagator

protected TwoBodyStoppablePropagator(@Nonnull
                                     TwoBodyStoppablePropagator existingInstance,
                                     @Nonnull
                                     CopyContext context)

Initializes a new instance as a copy of an existing instance.

See ICloneWithContext.clone(CopyContext) for more information about how to implement this constructor in a derived class.

Parameters:

existingInstance - The existing instance to copy.

context - A CopyContext that controls the depth of the copy.

Throws:

ArgumentNullException - Thrown when existingInstance or context is null.

Method Detail

clone

public Object clone(CopyContext context)

Clones this object using the specified context.

This method should be implemented to call a copy constructor on the class of the object being cloned. The copy constructor should take the CopyContext as a parameter in addition to the existing instance to copy. The copy constructor should first call CopyContext.addObjectMapping(T, T) to identify the newly constructed instance as a copy of the existing instance. It should then copy all fields, using CopyContext.updateReference(T) to copy any reference fields.

A typical implementation of ICloneWithContext:

public static class MyClass implements ICloneWithContext {
    public MyClass(MyClass existingInstance, CopyContext context) {
        context.addObjectMapping(existingInstance, this);
        someReference = context.updateReference(existingInstance.someReference);
    }

    @Override
    public final Object clone(CopyContext context) {
        return new MyClass(this, context);
    }

    private Object someReference;
}

In general, all fields that are reference types should be copied with a call to CopyContext.updateReference(T). There are a couple of exceptions:

1. Fields that are aggregate parts of the object should always be copied. A referenced object is an aggregate if properties or methods on the object being copied can modify the externally-visible value of the referenced object.
2. If the semantics of the referenced object require that it have a single parent, owner, context, etc., and the object being copied is that parent, owner, or context, then the referenced object should always be copied.

If one of these exceptions applies, the CopyContext should be given an opportunity to update the reference before the reference is copied explicitly. Use CopyContext.updateReference(T) to update the reference. If CopyContext.updateReference(T) returns the original object, indicating that the context does not have a replacement registered, then copy the object manually by invoking a Clone method, a copy constructor, or by manually constructing a new instance and copying the values.

alwaysCopy = context.updateReference(existingInstance.alwaysCopy);
if (existingInstance.alwaysCopy != null && alwaysCopy == existingInstance.alwaysCopy) {
    alwaysCopy = (AlwaysCopy) existingInstance.alwaysCopy.clone(context);
}

If you are implementing an evaluator (a class that implements IEvaluator), the IEvaluator.updateEvaluatorReferences(agi.foundation.infrastructure.CopyContext) method shares some responsibilities with the copy context constructor. Code duplication can be avoided by doing the following:

1. For references to other evaluators ONLY, simply assign the reference in the constructor instead of calling CopyContext.updateReference(T). You should still call CopyContext.updateReference(T) on any references to non-evaluators.
2. Call IEvaluator.updateEvaluatorReferences(agi.foundation.infrastructure.CopyContext) as the last line in the constructor and pass it the same CopyContext passed to the constructor.
3. Implement IEvaluator.updateEvaluatorReferences(agi.foundation.infrastructure.CopyContext) as normal. See the reference documentation for IEvaluator.updateEvaluatorReferences(agi.foundation.infrastructure.CopyContext) for more information on implementing that method.

public MyClass(MyClass existingInstance, CopyContext context) {
    super(existingInstance, context);
    someReference = context.updateReference(existingInstance.someReference);
    evaluatorReference = existingInstance.evaluatorReference;
    updateEvaluatorReferences(context);
}

@Override
public void updateEvaluatorReferences(CopyContext context) {
    evaluatorReference = context.updateReference(evaluatorReference);
}

@Override
public Object clone(CopyContext context) {
    return new MyClass(this, context);
}

private Object someReference;
private IEvaluator evaluatorReference;

Specified by:

clone in interface ICloneWithContext

Specified by:

clone in class DefinitionalObject

Parameters:

context - The context to use to perform the copy.

Returns:

A new instance which is a copy of this object.

checkForSameDefinition

protected final boolean checkForSameDefinition(SinglePointStoppablePropagatorDefinition other)

Checks to determine if another instance has the same definition as this instance and returns true if it does. Derived classes MUST override this method and check all new fields introduced by the derived class for definitional equivalence. It is NOT necessary to check base class fields because the base class will already have done that. When overriding this method, you should NOT call the base implementation because it will return false for all derived-class instances. Derived classes should check the type of other to preserve the symmetric nature of IEquatableDefinition.isSameDefinition(java.lang.Object).

Overrides:

checkForSameDefinition in class SinglePointStoppablePropagatorDefinition

Parameters:

other - The other instance to compare to this one.

Returns:

true if the two objects are defined equivalently; otherwise false.

checkForSameDefinition

protected boolean checkForSameDefinition(TwoBodyStoppablePropagator other)

Checks to determine if another instance has the same definition as this instance and returns true if it does. Derived classes MUST override this method and check all new fields introduced by the derived class for definitional equivalence. It is NOT necessary to check base class fields because the base class will already have done that. When overriding this method, you should NOT call the base implementation because it will return false for all derived-class instances. Derived classes should check the type of other to preserve the symmetric nature of IEquatableDefinition.isSameDefinition(java.lang.Object).

Parameters:

other - The other instance to compare to this one.

Returns:

true if the two objects are defined equivalently; otherwise false.

computeCurrentDefinitionHashCode

protected int computeCurrentDefinitionHashCode()

Computes a hash code based on the current properties of this object. Derived classes MUST override this method and compute a hash code that combines: a unique hash code seed, the base implementation result, and the hash codes of all new fields introduced by the derived class which are used in the TwoBodyStoppablePropagator.checkForSameDefinition(agi.foundation.propagators.SinglePointStoppablePropagatorDefinition) method.

Overrides:

computeCurrentDefinitionHashCode in class SinglePointStoppablePropagatorDefinition

Returns:

The computed hash code.

getGravitationalParameter

public final double getGravitationalParameter()

Gets the gravitational parameter of the central body that the propagated element is around.

setGravitationalParameter

public final void setGravitationalParameter(double value)

Sets the gravitational parameter of the central body that the propagated element is around.

createPropagator

protected SinglePointStoppablePropagator createPropagator(EvaluatorGroup group,
                                                          List<StateElementAdapterDefinition> previousAdapters)

Creates and initialize the actual SinglePointStoppablePropagator.

Specified by:

createPropagator in class SinglePointStoppablePropagatorDefinition

Parameters:

group - The group to use to initialize any evaluators that will be used.

previousAdapters - The previous adapters to use to configure this propagators adapters.

Returns:

The propagator for this SinglePointStoppablePropagatorDefinition.