agi.foundation.segmentpropagation

(agi.foundation.segmentpropagation-2024r2.jar)

Class NumericalPropagatorSegment

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.segmentpropagation.SegmentDefinition

agi.foundation.segmentpropagation.PropagateSegment

agi.foundation.segmentpropagation.NumericalPropagatorSegment

All Implemented Interfaces:

ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable

Direct Known Subclasses:

FiniteManeuverSegment

public class NumericalPropagatorSegment
extends PropagateSegment

A segment that will run a NumericalPropagator until a StoppingCondition is satisfied. Each StoppingCondition in the StoppingConditions (get) can have an optional SegmentDefinition associated with it that get propagated if that StoppingCondition is the one that stops the propagation of this segments propagator.

The results returned when this segments propagator is propagated will always be a PropagateSegmentResults.

The advantage to using this derived type as opposed to the PropagateSegment directly is that the configuration of the StateElementAdapters is handled automatically.

Note that this segment implements PropagateSegment and as such at propagation time, it is possible to configure a ChangePropagateSegmentsPropagatorOperator with any other StoppablePropagatorDefinition.

Constructor Summary

Constructors

Modifier	Constructor and Description
	NumericalPropagatorSegment() Initializes a new instance.
protected	NumericalPropagatorSegment(NumericalPropagatorSegment 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(NumericalPropagatorSegment other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(PropagateSegment 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 SegmentPropagator	createSegmentPropagator(EvaluatorGroup group, SegmentDefinition previousSegment) Creates, configures, and returns the SegmentPropagator for this segment.
void	enumerateDependencies(DependencyEnumerator enumerator) Enumerates the dependencies of this object by calling DependencyEnumerator#enumerate(T) for each object that this object directly depends upon.
protected void	freezeAggregatedObjects() Called by DefinitionalObject.freeze() to also freeze any objects that are considered to be a part of this object.
Object	getDefinedIn(String element) Gets the object (for example, a ReferenceFrame, an Axes, etc.) in which the specified element is defined in.
StateElementAdapterDefinition	getElementAdapter(String element) Returns the adapter for the given state element.
List<String>	getElements() Gets the names of all of the elements that this segment is propagating.
NumericalPropagatorDefinition	getPropagatorDefinition() Gets the NumericalPropagatorDefinition that contains all of elements that will be propagated by this segment.
boolean	setElementAndAdapter(StateElementAdapterDefinition adapter) Add or sets an adapter for an element in this segment.
void	setPropagatorDefinition(NumericalPropagatorDefinition value) Sets the NumericalPropagatorDefinition that contains all of elements that will be propagated by this segment.

Methods inherited from class agi.foundation.segmentpropagation.PropagateSegment

addPropagationFinishedEvent, addStepTaken, checkForSameDefinition, clearStoppingConditionsAutoSegment, getAllowZeroElements, getMaximumDuration, getNumberOfTimesToExecuteStoppingConditionsAutoSegment, getOutputSparsity, getStopOnMaximumDurationBehavior, getStoppablePropagator, getStoppingConditions, getStoppingConditionsAutoSegment, removePropagationFinishedEvent, removeStepTaken, setMaximumDuration, setOutputSparsity, setStopOnMaximumDurationBehavior, setStoppablePropagator, setStoppingConditionAutoSegment

Methods inherited from class agi.foundation.segmentpropagation.SegmentDefinition

checkForSameDefinition, containsElement, getName, getNextStateBehavior, getPassAllElementsToNextSegment, getPropagationDirection, getSegmentPropagator, getSegmentPropagator, getSegmentPropagator, getSegmentPropagator, removeElement, setName, setNextStateBehavior, setPropagationDirection, toString

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, wait, wait, wait

Constructor Detail

NumericalPropagatorSegment

public NumericalPropagatorSegment()

Initializes a new instance. The PropagatorDefinition (get / set) must be set, and at least one StoppingCondition must be added to the StoppingConditions (get) before the SegmentPropagator for this SegmentDefinition can be created.

NumericalPropagatorSegment

protected NumericalPropagatorSegment(@Nonnull
                                     NumericalPropagatorSegment 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

Overrides:

clone in class PropagateSegment

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(PropagateSegment 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 PropagateSegment

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(NumericalPropagatorSegment 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 NumericalPropagatorSegment.checkForSameDefinition(agi.foundation.segmentpropagation.PropagateSegment) method.

Overrides:

computeCurrentDefinitionHashCode in class PropagateSegment

Returns:

The computed hash code.

enumerateDependencies

public void enumerateDependencies(DependencyEnumerator enumerator)

Enumerates the dependencies of this object by calling DependencyEnumerator#enumerate(T) for each object that this object directly depends upon. Derived classes which contain additional dependencies MUST override this method, call the base implementation, and enumerate dependencies introduced by the derived class.

Specified by:

enumerateDependencies in interface IEnumerateDependencies

Overrides:

enumerateDependencies in class PropagateSegment

Parameters:

enumerator - The enumerator that is informed of the dependencies of this object.

freezeAggregatedObjects

protected void freezeAggregatedObjects()

Called by DefinitionalObject.freeze() to also freeze any objects that are considered to be a part of this object. Derived classes which contain additional aggregated objects MUST override this method, call the base implementation, and freeze aggregated objects introduced by the derived class. The objects that need to be frozen in this method are frequently created in this object's constructor and are not settable via properties.

Overrides:

freezeAggregatedObjects in class PropagateSegment

getElementAdapter

public StateElementAdapterDefinition getElementAdapter(String element)

Returns the adapter for the given state element. The StateElementAdapters handle the various transformations of the propagated elements between segments (for example, if the integration frame of a point being propagated changes from one segment to another, the adapter is what handles that transformation between segment). All elements propagated by this segment must have an adapter returned by this method (even if that adapter simply returns the original state). If multiple segments are being propagated by this segment (as a SegmentList would), this must return the adapter of the StateElementAdapter of the element for the final known segment getting propagated.

In general, the concrete SegmentDefinition should have a list of the adapter factory instances that are valid for this segment, and then this method would get the element definition object from this segments configuration.

Overrides:

getElementAdapter in class SegmentDefinition

Parameters:

element - The element whose StateElementAdapter is needed.

Returns:

The adapter with the element defined-in set, or null if there is no such factory.

setElementAndAdapter

public boolean setElementAndAdapter(StateElementAdapterDefinition adapter)

Add or sets an adapter for an element in this segment.

Note that many types of derived segments will automatically handle their adapters by interrogating properties specific to the derived segment. Also some segments whose PassAllElementsToNextSegment (get) property is true do not require adapters or elements to be set.

These adapters have the responsibility of processing the initial state that the propagator will start propagating from. They will modify the initial state passed to this segment so that the state is in a form that the propagator can process.

Overrides:

setElementAndAdapter in class SegmentDefinition

Parameters:

adapter - An instance of the factory that makes the adapter. This must be configured with the current defined in object (if appropriate) and with the element identification.

Returns:

true if the element was added or set successfully; otherwise false. false does not indicate an error; it means that this segment does not need elements and adapters explicitly set.

getElements

public List<String> getElements()

Gets the names of all of the elements that this segment is propagating.

Unless the logic of a derived segment requires it, there is no requirement that the same elements get propagated from segment to segment (for example, you can propagate a satellite and the booster that got it into orbit. When the booster reenters the atmosphere, you do not have to keep that element around in later segments). However values that you want to be propagated from segment to segment must have the same name (continuing the example, the name of the satellite getting propagated needs to be consistent from segment to segment).

Overrides:

getElements in class SegmentDefinition

getPropagatorDefinition

public final NumericalPropagatorDefinition getPropagatorDefinition()

Gets the NumericalPropagatorDefinition that contains all of elements that will be propagated by this segment. Note that this simply reflects the PropagatorDefinition (get / set) of the StoppablePropagator (get / set) so changing the base property will change this as well.

setPropagatorDefinition

public final void setPropagatorDefinition(NumericalPropagatorDefinition value)

Sets the NumericalPropagatorDefinition that contains all of elements that will be propagated by this segment. Note that this simply reflects the PropagatorDefinition (get / set) of the StoppablePropagator (get / set) so changing the base property will change this as well.

getDefinedIn

public Object getDefinedIn(String element)

Gets the object (for example, a ReferenceFrame, an Axes, etc.) in which the specified element is defined in. This can return null if there is no such object. When overriding this method, you generally should not call the base method, instead the derived segment should keep track of the elements and defined in objects itself.

Overrides:

getDefinedIn in class SegmentDefinition

Parameters:

element - The identification of the element.

Returns:

The defined in object for the element.

createSegmentPropagator

protected SegmentPropagator createSegmentPropagator(EvaluatorGroup group,
                                                    SegmentDefinition previousSegment)

Creates, configures, and returns the SegmentPropagator for this segment. This method should check that all of the required properties on the concrete instance are configured properly before constructing the SegmentPropagator to be returned.

Overrides:

createSegmentPropagator in class PropagateSegment

Parameters:

group - The group to use during creation.

previousSegment - The previous segment. Some segments will require the previousSegment to be set, whereas other will require that the previous segment not be null, whereas others will only use information from it if provided. It is up to you writing a concrete type to enforce what makes sense for your particular segment in this method.

Returns:

The propagator for this segment.