agi.foundation.geometry

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

Class VectorBPlane

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.geometry.Vector

agi.foundation.geometry.VectorBPlane

All Implemented Interfaces:

ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable, IServiceProvider

public class VectorBPlane
extends Vector

A vector computing the B-Plane vector of a Point relative to a CentralBody (get / set).

The b-plane is the basis for a coordinate system that can assist in targeting a trajectory during a gravitational assist. The b-plane itself is the plane that is perpendicular to the incoming asymptote of a hyperbolic trajectory and centered on the planet it is approaching. To form the rest of the coordinates, that plane is aligned generally with the planets pole vector, or to the Z component of an arbitrary ParentReferenceFrame (get / set) centered on the planet. This vector points to where the incoming asymptote intersects with the b-plane.

In its native frame, there is no Z component to this Vector. The X component is can be computed with the VectorBPlane.getBDotT(). Likewise the Y component, R, can be computed with VectorBPlane.getBDotR().

Remember that this is not where the actual trajectory intersects with the b-plane, just the asymptote of a hyperbolic trajectory.

Constructor Summary

Constructors

Modifier	Constructor and Description
	VectorBPlane() Initializes a new instance.
	VectorBPlane(Point location, CentralBody centralBody, double gravitationalParameter) Initializes a new instance.
	VectorBPlane(Point location, CentralBody centralBody, double gravitationalParameter, ReferenceFrame parentReferenceFrame) Initializes a new instance.
protected	VectorBPlane(VectorBPlane 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(Vector other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(VectorBPlane 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.
void	enumerateDependencies(DependencyEnumerator enumerator) Enumerates the dependencies of this object by calling DependencyEnumerator#enumerate(T) for each object that this object directly depends upon.
Scalar	getBDotR() Returns a Scalar that represents the value of this VectorBPlane doted with the B-Plane R vector.
Scalar	getBDotT() Returns a Scalar that represents the value of this VectorBPlane doted with the B-Plane T vector.
CentralBody	getCentralBody() Gets the CentralBody (get / set) to use.
VectorEvaluator	getEvaluator(EvaluatorGroup group) Gets an evaluator that can be used to find the Motion<Cartesian> of this vector in its parent Axes at a given JulianDate.
double	getGravitationalParameter() Gets the gravitational parameter of the CentralBody (get / set).
Point	getOrbitalPoint() Gets the Point to use when computing this VectorBPlane.
ReferenceFrame	getParentReferenceFrame() Gets the ReferenceFrame that the CentralBody (get / set) will be defined in.
void	setCentralBody(CentralBody value) Sets the CentralBody (get / set) to use.
void	setGravitationalParameter(double value) Sets the gravitational parameter of the CentralBody (get / set).
void	setOrbitalPoint(Point value) Sets the Point to use when computing this VectorBPlane.
void	setParentReferenceFrame(ReferenceFrame value) Sets the ReferenceFrame that the CentralBody (get / set) will be defined in.

Methods inherited from class agi.foundation.geometry.Vector

add, add, checkForSameDefinition, createVectorDerivative, cross, divide, divide, divide, divide, dot, getEvaluator, getScalarElement, getScalarElement, getService, multiply, multiply, multiply, multiply, multiply, multiply, subtract, subtract

Methods inherited from class agi.foundation.infrastructure.DefinitionalObject

areSameDefinition, areSameDefinition, areSameDefinition, areSameDefinition, areSameDefinition, collectionItemsAreSameDefinition, collectionItemsAreSameDefinition, collectionItemsAreSameDefinition, dictionaryItemsAreSameDefinition, freeze, freezeAggregatedObjects, 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

VectorBPlane

public VectorBPlane()

Initializes a new instance. By default the CentralBody (get / set) will be Earth and the GravitationalParameter (get / set) will be set to WorldGeodeticSystem1984.GravitationalParameter.

VectorBPlane

public VectorBPlane(Point location,
                    CentralBody centralBody,
                    double gravitationalParameter)

Initializes a new instance.

Parameters:

location - The location of the satellite approaching the centralBody.

centralBody - The CentralBody (get / set) the location is relative to.

gravitationalParameter - The gravitational parameter of centralBody.

VectorBPlane

public VectorBPlane(Point location,
                    CentralBody centralBody,
                    double gravitationalParameter,
                    ReferenceFrame parentReferenceFrame)

Initializes a new instance.

Parameters:

location - The location of the satellite approaching the centralBody.

centralBody - The CentralBody (get / set) the location is relative to.

gravitationalParameter - The gravitational parameter of centralBody.

parentReferenceFrame - The ReferenceFrame that the centralBody should be computed in. If this is null then the pole vector will be used to orient the B-plane.

VectorBPlane

protected VectorBPlane(@Nonnull
                       VectorBPlane 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(Vector 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).

Specified by:

checkForSameDefinition in class Vector

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(VectorBPlane 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 VectorBPlane.checkForSameDefinition(agi.foundation.geometry.Vector) method.

Overrides:

computeCurrentDefinitionHashCode in class Vector

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 DefinitionalObject

Parameters:

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

getOrbitalPoint

public final Point getOrbitalPoint()

Gets the Point to use when computing this VectorBPlane. This must provide position and velocity information.

setOrbitalPoint

public final void setOrbitalPoint(Point value)

Sets the Point to use when computing this VectorBPlane. This must provide position and velocity information.

getCentralBody

public final CentralBody getCentralBody()

Gets the CentralBody (get / set) to use.

setCentralBody

public final void setCentralBody(CentralBody value)

Sets the CentralBody (get / set) to use.

getGravitationalParameter

public final double getGravitationalParameter()

Gets the gravitational parameter of the CentralBody (get / set).

setGravitationalParameter

public final void setGravitationalParameter(double value)

Sets the gravitational parameter of the CentralBody (get / set).

getParentReferenceFrame

public final ReferenceFrame getParentReferenceFrame()

Gets the ReferenceFrame that the CentralBody (get / set) will be defined in. If this is null then the Z component of the CentralBody (get / set) fixed frame will be used in orientating the VectorBPlane.

setParentReferenceFrame

public final void setParentReferenceFrame(ReferenceFrame value)

Sets the ReferenceFrame that the CentralBody (get / set) will be defined in. If this is null then the Z component of the CentralBody (get / set) fixed frame will be used in orientating the VectorBPlane.

getBDotT

@Nonnull
public final Scalar getBDotT()

Returns a Scalar that represents the value of this VectorBPlane doted with the B-Plane T vector.

Returns:

The Scalar that represents the value of B doted with the T vector.

getBDotR

@Nonnull
public final Scalar getBDotR()

Returns a Scalar that represents the value of this VectorBPlane doted with the B-Plane R vector.

Returns:

The Scalar that represents the value of B doted with the R vector.

getEvaluator

public VectorEvaluator getEvaluator(EvaluatorGroup group)

Gets an evaluator that can be used to find the Motion<Cartesian> of this vector in its parent Axes at a given JulianDate. Consider using the methods of GeometryTransformer instead of calling this method directly.

Specified by:

getEvaluator in class Vector

Parameters:

group - The group with which to associate the new evaluator. By grouping evaluators that are often evaluated at the same Julian dates, common computations can be performed only once for the entire group instead of multiple times for each evaluator.

Returns:

An evaluator for this vector.