agi.foundation.geometry

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

Class AxesNorthEastDown

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.geometry.Axes

agi.foundation.geometry.AxesNorthEastDown

All Implemented Interfaces:

ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable, IServiceProvider

public class AxesNorthEastDown
extends Axes

The set of axes defined by the local North, East, and Down directions at a point with respect to the shape of a central body as the point moves over time.

The axes is defined such that:

• The X axis points in the local North direction.
• The Y axis points in the local East direction.
• The Z axis points in the local Down direction (the direction opposite the surface normal direction which passes through the point).

Constructor Summary

Constructors

Modifier	Constructor and Description
	AxesNorthEastDown() Initialize a new instance.
protected	AxesNorthEastDown(AxesNorthEastDown existingInstance, CopyContext context) Initializes a new instance as a copy of an existing instance.
	AxesNorthEastDown(CentralBody centralBody, Point referencePoint) Initializes a new instance.

Method Summary

Modifier and Type	Method and Description
protected boolean	checkForSameDefinition(Axes other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(AxesNorthEastDown 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.
static UnitQuaternion	computeFixedToNorthEastDownRotation(Ellipsoid shape, Cartesian fixedReferencePoint) Computes the rotation from the central body's fixed axes to a set of north-east-down axes based on a specified reference point.
static Motion2<UnitQuaternion,Cartesian>	computeFixedToNorthEastDownRotation(Ellipsoid shape, Motion1<Cartesian> fixedReferencePoint, int order) Computes the rotation from the central body's fixed axes to a set of north-east-down axes based on a specified reference point.
void	enumerateDependencies(DependencyEnumerator enumerator) Enumerates the dependencies of this object by calling DependencyEnumerator#enumerate(T) for each object that this object directly depends upon.
CentralBody	getCentralBody() Gets the central body that defines the surface.
AxesEvaluator	getEvaluator(EvaluatorGroup group) Gets an evaluator that can be used to find the transformation from ReferencePoint (get / set)'s Axes (get / set) to a new Axes defined by the North-East-Down convention at a given JulianDate.
Point	getReferencePoint() Gets the reference point that defines the axes.
void	setCentralBody(CentralBody value) Sets the central body that defines the surface.
void	setReferencePoint(Point value) Sets the reference point that defines the axes.

Methods inherited from class agi.foundation.geometry.Axes

checkForSameDefinition, getEvaluator, getRoot, getService, getVectorElement, getVectorElement

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

AxesNorthEastDown

public AxesNorthEastDown()

Initialize a new instance. The user must set ReferencePoint (get / set) and CentralBody (get / set).

AxesNorthEastDown

public AxesNorthEastDown(CentralBody centralBody,
                         Point referencePoint)

Initializes a new instance.

Parameters:

centralBody - The central body that defines the surface.

referencePoint - The reference point that defines the axes.

AxesNorthEastDown

protected AxesNorthEastDown(@Nonnull
                            AxesNorthEastDown 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(Axes 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 Axes

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(AxesNorthEastDown 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 AxesNorthEastDown.checkForSameDefinition(agi.foundation.geometry.Axes) method.

Overrides:

computeCurrentDefinitionHashCode in class Axes

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.

getCentralBody

public final CentralBody getCentralBody()

Gets the central body that defines the surface.

setCentralBody

public final void setCentralBody(CentralBody value)

Sets the central body that defines the surface.

getReferencePoint

public final Point getReferencePoint()

Gets the reference point that defines the axes.

setReferencePoint

public final void setReferencePoint(Point value)

Sets the reference point that defines the axes.

computeFixedToNorthEastDownRotation

@Nonnull
public static UnitQuaternion computeFixedToNorthEastDownRotation(Ellipsoid shape,
                                                                           @Nonnull
                                                                           Cartesian fixedReferencePoint)

Computes the rotation from the central body's fixed axes to a set of north-east-down axes based on a specified reference point. In these axes, the X axis points toward the local North, the Y axis points toward the local East, and the Z axis points down (opposite the surface normal).

Parameters:

shape - The shape of the central body.

fixedReferencePoint - The position of the reference point in the central body's fixed frame.

Returns:

A transformation from the ellipsoid fixed axes to north-east-down axes.

computeFixedToNorthEastDownRotation

@Nonnull
public static Motion2<UnitQuaternion,Cartesian> computeFixedToNorthEastDownRotation(Ellipsoid shape,
                                                                                              @Nonnull
                                                                                              Motion1<Cartesian> fixedReferencePoint,
                                                                                              int order)

Computes the rotation from the central body's fixed axes to a set of north-east-down axes based on a specified reference point. In these axes, the X axis points toward the local North, the Y axis points toward the local East, and the Z axis points down (opposite the surface normal).

Parameters:

shape - The shape of the central body.

fixedReferencePoint - The motion of the reference point in the central body's fixed frame.

order - The order of the highest derivative to compute. To compute just the rotation, pass 0 for this value. To compute rotational velocity as well, pass 1.

Returns:

A transformation from the ellipsoid fixed axes to north-east-down axes.

getEvaluator

public AxesEvaluator getEvaluator(EvaluatorGroup group)

Gets an evaluator that can be used to find the transformation from ReferencePoint (get / set)'s Axes (get / set) to a new Axes defined by the North-East-Down convention at a given JulianDate. The new axes will be represented by a Motion<UnitQuaternion, Cartesian> specifying the orientation of these Axes. Derivative information is provided if Point provides derivatives.

Specified by:

getEvaluator in class Axes

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 Axes.

Throws:

ArgumentNullException - Thrown if group is null.

PropertyInvalidException - Thrown if ReferencePoint (get / set) or CentralBody (get / set) is null.