agi.foundation.spice

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

Class CeresBspEphemerisProvider

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.spice.JplSpkEphemerisProvider

agi.foundation.spice.CeresBspEphemerisProvider

All Implemented Interfaces:

ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable

public class CeresBspEphemerisProvider
extends JplSpkEphemerisProvider

Provides access to the position of Ceres with respect to the Sun.

The ceres.bsp ephemeris file can be created using the website of the Solar System Dynamics (SSD) group of JPL to build your own ceres.bsp files for Ceres. First, the target body needs to be set to Ceres and the time specification needs to be set for the desired time period. If the ephemeris type is set to "Small-Body SPK File", clicking "Generate Ephemeris" will create and download a 2000001.bsp ephemeris for Ceres. Go to your local Downloads folder and rename the file to ceres.bsp. This file can then be used with this class to provide ephemeris for asteroids.

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method and Description
protected boolean	checkForSameDefinition(CeresBspEphemerisProvider other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(JplSpkEphemerisProvider 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	getCeresPoint() Gets a point representing the center of mass location of the dwarf planet Ceres in a reference frame centered at the current value of SunPoint (get / set).
Point	getSunPoint() Gets a point representing the location of the Sun.
void	setSunPoint(Point value) Sets a point representing the location of the Sun.
void	useForCentralBodyPositions(CentralBodiesFacet centralBodiesFacet) Uses this ephemeris provider for the position of the center of mass of Ceres 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

CeresBspEphemerisProvider

public CeresBspEphemerisProvider(@Nonnull
                                 String filename,
                                 @Nonnull
                                 Point sunPoint)

Initializes an instance using the specified ceres.bsp filename.

Parameters:

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

sunPoint - The point around which Ceres is 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 sunPoint is null.

CeresBspEphemerisProvider

public CeresBspEphemerisProvider(@Nonnull
                                 StreamFactory streamFactory,
                                 @Nonnull
                                 Point sunPoint)

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.

sunPoint - The point around which Ceres is 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 sunPoint is null.

CeresBspEphemerisProvider

public CeresBspEphemerisProvider(@Nonnull
                                 JplSpkFile file,
                                 @Nonnull
                                 Point sunPoint)

Initializes an instance using the specified JplSpkFile instance.

Parameters:

file - The JplSpkFile instance to use.

sunPoint - The point around which Ceres is 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 sunPoint is null.

CeresBspEphemerisProvider

protected CeresBspEphemerisProvider(@Nonnull
                                    CeresBspEphemerisProvider 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(CeresBspEphemerisProvider 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 CeresBspEphemerisProvider.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 position of the center of mass of Ceres in the specified CentralBodiesFacet instance. This also sets the position of the Sun.

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

Specified by:

useForCentralBodyPositions in class JplSpkEphemerisProvider

Parameters:

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

Throws:

ArgumentNullException - Thrown when centralBodiesFacet is null.

getSunPoint

@Nonnull
public final Point getSunPoint()

Gets a point representing the location of the Sun. Setting this point will also cause the point in this class representing Ceres to be modeled as orbiting this updated point.

setSunPoint

public final void setSunPoint(@Nonnull
                              Point value)

Sets a point representing the location of the Sun. Setting this point will also cause the point in this class representing Ceres to be modeled as orbiting this updated point.

getCeresPoint

@Nonnull
public final Point getCeresPoint()

Gets a point representing the center of mass location of the dwarf planet Ceres in a reference frame centered at the current value of SunPoint (get / set).