agi.foundation.spice

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

Class SaturnBspEphemerisProvider

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.spice.JplSpkEphemerisProvider

agi.foundation.spice.SaturnBspEphemerisProvider

All Implemented Interfaces:

ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable

Direct Known Subclasses:

Sat441BspEphemerisProvider

public class SaturnBspEphemerisProvider
extends JplSpkEphemerisProvider

Provides access to the positions of the nine major moons of Saturn with respect to the Saturn system barycenter.

If STK is installed with the Planetary Data Supplement, the file saturn.bsp is available in the STKData/Spice folder of the STK installation. This should be used as input for the constructors of this class.

If STK or the Planetary Data Supplement are unavailable, the next best option is to go to the website of the Navigation and Ancillary Information Facility (NAIF) of JPL to download the sat441.bsp ephemeris for Saturn and its moons. This file is massive (646 MB) because it contains data that extends hundreds of years into the past and future for astronomical purposes. There is a small text sat441.cmt file in that directory that contains information about what data is contained within the sat441.bsp file. While this file is compatible with this base class, it is recommended that it is used with the derived class Jup365BspEphemerisProvider instead because the derived class provides additional functionality associated with the physical center of mass of Saturn and some of the smaller moons of Saturn.

Constructor Summary

Constructors

Modifier	Constructor and Description
	SaturnBspEphemerisProvider(JplSpkFile file, Point saturnSystemBarycenter) Initializes an instance using the specified JplSpkFile instance.
protected	SaturnBspEphemerisProvider(SaturnBspEphemerisProvider existingInstance, CopyContext context) Initializes a new instance as a copy of an existing instance.
	SaturnBspEphemerisProvider(StreamFactory streamFactory, Point saturnSystemBarycenter) Initializes a new instance with the specified stream factory.
	SaturnBspEphemerisProvider(String filename, Point saturnSystemBarycenter) Initializes an instance using the specified saturn.bsp filename.

Method Summary

Modifier and Type	Method and Description
protected boolean	checkForSameDefinition(JplSpkEphemerisProvider other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(SaturnBspEphemerisProvider 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.
protected void	freezeAggregatedObjects() Called by DefinitionalObject.freeze() to also freeze any objects that are considered to be a part of this object.
Point	getDionePoint() Gets a point representing the center of mass location of the moon Dione in a reference frame centered at the current value of SaturnSystemBarycenter (get / set).
Point	getEnceladusPoint() Gets a point representing the center of mass location of the moon Enceladus in a reference frame centered at the current value of SaturnSystemBarycenter (get / set).
Point	getHyperionPoint() Gets a point representing the center of mass location of the moon Hyperion in a reference frame centered at the current value of SaturnSystemBarycenter (get / set).
Point	getIapetusPoint() Gets a point representing the center of mass location of the moon Iapetus in a reference frame centered at the current value of SaturnSystemBarycenter (get / set).
Point	getMimasPoint() Gets a point representing the center of mass location of the moon Mimas in a reference frame centered at the current value of SaturnSystemBarycenter (get / set).
Point	getPhoebePoint() Gets a point representing the center of mass location of the moon Phoebe in a reference frame centered at the current value of SaturnSystemBarycenter (get / set).
Point	getRheaPoint() Gets a point representing the center of mass location of the moon Rhea in a reference frame centered at the current value of SaturnSystemBarycenter (get / set).
Point	getSaturnSystemBarycenter() Gets a point representing the location of the barycenter of the Saturn planetary system.
Point	getTethysPoint() Gets a point representing the center of mass location of the moon Tethys in a reference frame centered at the current value of SaturnSystemBarycenter (get / set).
Point	getTitanPoint() Gets a point representing the center of mass location of the moon Titan in a reference frame centered at the current value of SaturnSystemBarycenter (get / set).
void	setSaturnSystemBarycenter(Point value) Sets a point representing the location of the barycenter of the Saturn planetary system.
void	useForCentralBodyPositions(CentralBodiesFacet centralBodiesFacet) Uses this ephemeris provider for the positions of the centers of mass of the nine major moons of Saturn in the specified CentralBodiesFacet instance.

Methods inherited from class agi.foundation.spice.JplSpkEphemerisProvider

checkForSameDefinition, getFile, modelSolarSystemUsingPlanetaryDataSupplement, modelSolarSystemUsingPublicJplData

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

SaturnBspEphemerisProvider

public SaturnBspEphemerisProvider(@Nonnull
                                  String filename,
                                  @Nonnull
                                  Point saturnSystemBarycenter)

Initializes an instance using the specified saturn.bsp filename.

Parameters:

filename - The full path and filename of the saturn.bsp file.

saturnSystemBarycenter - The point around which the moons of Saturn are defined to orbit. This should be updated using JplDE.useForCentralBodyPositions(agi.foundation.celestial.CentralBodiesFacet) or PlanetsBspEphemerisProvider.useForCentralBodyPositions(agi.foundation.celestial.CentralBodiesFacet) before being extracted to use in this constructor.

Throws:

ArgumentNullException - Thrown when filename or saturnSystemBarycenter is null.

SaturnBspEphemerisProvider

public SaturnBspEphemerisProvider(@Nonnull
                                  StreamFactory streamFactory,
                                  @Nonnull
                                  Point saturnSystemBarycenter)

Initializes a new instance with the specified stream factory.

The streams created by streamFactory must support seeking. This means that the streams must implement ISeekableStream or FileInputStream.

Parameters:

streamFactory - The factory to use to create streams to read the JPL SPK data.

saturnSystemBarycenter - The point around which the moons of Saturn are defined to orbit. This should be updated using JplDE.useForCentralBodyPositions(agi.foundation.celestial.CentralBodiesFacet) or PlanetsBspEphemerisProvider.useForCentralBodyPositions(agi.foundation.celestial.CentralBodiesFacet) before being extracted to use in this constructor.

Throws:

ArgumentNullException - Thrown when streamFactory or saturnSystemBarycenter is null.

SaturnBspEphemerisProvider

public SaturnBspEphemerisProvider(@Nonnull
                                  JplSpkFile file,
                                  @Nonnull
                                  Point saturnSystemBarycenter)

Initializes an instance using the specified JplSpkFile instance.

Parameters:

file - The JplSpkFile instance to use.

saturnSystemBarycenter - The point around which the moons of Saturn are defined to orbit. This should be updated using JplDE.useForCentralBodyPositions(agi.foundation.celestial.CentralBodiesFacet) or PlanetsBspEphemerisProvider.useForCentralBodyPositions(agi.foundation.celestial.CentralBodiesFacet) before being extracted to use in this constructor.

Throws:

ArgumentNullException - Thrown when file or saturnSystemBarycenter is null.

SaturnBspEphemerisProvider

protected SaturnBspEphemerisProvider(@Nonnull
                                     SaturnBspEphemerisProvider 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(JplSpkEphemerisProvider 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 JplSpkEphemerisProvider

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(SaturnBspEphemerisProvider 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 SaturnBspEphemerisProvider.checkForSameDefinition(agi.foundation.spice.JplSpkEphemerisProvider) method.

Overrides:

computeCurrentDefinitionHashCode in class JplSpkEphemerisProvider

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 JplSpkEphemerisProvider

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 JplSpkEphemerisProvider

useForCentralBodyPositions

public void useForCentralBodyPositions(CentralBodiesFacet centralBodiesFacet)

Uses this ephemeris provider for the positions of the centers of mass of the nine major moons of Saturn in the specified CentralBodiesFacet instance. This also sets the position of the SaturnSystemBarycenter (get / set). This does not set the position of SaturnCentralBody unless this class is also a Sat441BspEphemerisProvider and the sat441.bsp file is used.

To use this ephemeris provider for only the Saturn system barycenter or one of the moons, use one of the available points. This method also calls CentralBody.synchronizeOrigins() on the barycenter and moons.

Specified by:

useForCentralBodyPositions in class JplSpkEphemerisProvider

Parameters:

centralBodiesFacet - The central bodies to update to use this data.

Throws:

ArgumentNullException - Thrown when centralBodiesFacet is null.

getSaturnSystemBarycenter

@Nonnull
public Point getSaturnSystemBarycenter()

Gets a point representing the location of the barycenter of the Saturn planetary system. Setting this point will also cause the points in this class representing the moons of Saturn to be modeled as orbiting this updated point.

setSaturnSystemBarycenter

public void setSaturnSystemBarycenter(@Nonnull
                                      Point value)

Sets a point representing the location of the barycenter of the Saturn planetary system. Setting this point will also cause the points in this class representing the moons of Saturn to be modeled as orbiting this updated point.

getMimasPoint

@Nonnull
public final Point getMimasPoint()

Gets a point representing the center of mass location of the moon Mimas in a reference frame centered at the current value of SaturnSystemBarycenter (get / set).

getEnceladusPoint

@Nonnull
public final Point getEnceladusPoint()

Gets a point representing the center of mass location of the moon Enceladus in a reference frame centered at the current value of SaturnSystemBarycenter (get / set).

getTethysPoint

@Nonnull
public final Point getTethysPoint()

Gets a point representing the center of mass location of the moon Tethys in a reference frame centered at the current value of SaturnSystemBarycenter (get / set).

getDionePoint

@Nonnull
public final Point getDionePoint()

Gets a point representing the center of mass location of the moon Dione in a reference frame centered at the current value of SaturnSystemBarycenter (get / set).

getRheaPoint

@Nonnull
public final Point getRheaPoint()

Gets a point representing the center of mass location of the moon Rhea in a reference frame centered at the current value of SaturnSystemBarycenter (get / set).

getTitanPoint

@Nonnull
public final Point getTitanPoint()

Gets a point representing the center of mass location of the moon Titan in a reference frame centered at the current value of SaturnSystemBarycenter (get / set).

getHyperionPoint

@Nonnull
public final Point getHyperionPoint()

Gets a point representing the center of mass location of the moon Hyperion in a reference frame centered at the current value of SaturnSystemBarycenter (get / set).

getIapetusPoint

@Nonnull
public final Point getIapetusPoint()

Gets a point representing the center of mass location of the moon Iapetus in a reference frame centered at the current value of SaturnSystemBarycenter (get / set).

getPhoebePoint

@Nonnull
public final Point getPhoebePoint()

Gets a point representing the center of mass location of the moon Phoebe in a reference frame centered at the current value of SaturnSystemBarycenter (get / set).