agi.foundation.celestial

(agi.foundation.models-2024r1.jar)

Class JplDE430

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.celestial.JplDE

agi.foundation.celestial.JplDE430

All Implemented Interfaces:

IJplDEWithMoonLibrationModel, ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable

public class JplDE430
extends JplDE
implements IJplDEWithMoonLibrationModel

Represents JPL DE430 ephemeris data.

The following example shows how to load a JPL DE file and use its data for the positions of the centers of mass of the central bodies in a CentralBodiesFacet:

// Load a JplDE file using a string that represents the JplDE file
JplDE430 jplde = new JplDE430(new File(dataPath, "plneph.430").getPath());

// Use the JplDE data in a CentralBodiesFacet
CentralBodiesFacet centralBodies = CentralBodiesFacet.getFromContext();
jplde.useForCentralBodyPositions(centralBodies);

// Optional - use the JplDE data for the Lunar fixed frame
MoonCentralBody moon = centralBodies.getMoon();
moon.setFixedFrame(jplde.getMoonFixedFrame());

JPL Planetary Ephemeris files can be downloaded from https://ftp.agi.com/pub/STKData/Astro/PlanetEphem/lendian/.

Field Summary

Fields

Modifier and Type	Field and Description
static int	EphemerisNumber The PlanetaryEphemerisNumber (get) represented by this class.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	JplDE430(JplDE430 existingInstance, CopyContext context) Initializes a new instance as a copy of an existing instance.
	JplDE430(JplDEFile file) Initializes an instance using the specified JplDEFile instance.
	JplDE430(StreamFactory streamFactory) Initializes a new instance with the specified stream factory.
	JplDE430(String fileName) Initializes an instance using the specified JPL DE filename.

Method Summary

Modifier and Type	Method and Description
protected boolean	checkForSameDefinition(JplDE other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(JplDE430 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.
double	getEarthRadius() Gets the radius of Earth in kilometers.
ReferenceFrame	getMoonFixedFrame() Uses the JplDE430 data to return the orientation and position of the Moon's principal axes of inertia to define a fixed frame.
LibrationModel	getMoonLibrationModel() Gets a libration model for the Moon.
ReferenceFrame	getMoonTopographicFixedFrame() Uses the JplDE430 data to return the orientation and position of the Moon's "Mean Earth" axes which define a fixed frame with the z-axis pointing toward the mean axis of rotation, the x-axis pointing toward the mean direction to the Earth, and the y-axis orthogonal.
String	getSource() Gets the string describing the source of the data.

Methods inherited from class agi.foundation.celestial.JplDE

checkForSameDefinition, createEarthMoonBarycenterPoint, enumerateDependencies, freezeAggregatedObjects, getCenterOfMassPoint, getEarthMoonMassRatio, getEarthNutationModel, getFile, getFinalEpoch, getGravitationalParameter, getGravitationalParameterNative, getInitialEpoch, getKilometersPerAstronomicalUnit, getLunarEphemerisNumber, getPlanetaryEphemerisNumber, getSpeedOfLight, getTitles, useForCentralBodyPositions

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

Field Detail

EphemerisNumber

public static final int EphemerisNumber

The PlanetaryEphemerisNumber (get) represented by this class.

See Also:

Constant Field Values

Constructor Detail

JplDE430

public JplDE430(@Nonnull
                String fileName)

Initializes an instance using the specified JPL DE filename.

Parameters:

fileName - The full path and filename of the JPL DE file.

Throws:

ArgumentException - Thrown when the file specified by the fileName is not a valid JplDE430 file.

ArgumentNullException - Thrown when fileName is null.

JplDE430

public JplDE430(@Nonnull
                StreamFactory streamFactory)

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 DE data.

Throws:

ArgumentException - Thrown when the file specified by the streamFactory is not a valid JplDE430 file.

ArgumentNullException - Thrown when streamFactory is null.

JplDE430

public JplDE430(@Nonnull
                JplDEFile file)

Initializes an instance using the specified JplDEFile instance.

Parameters:

file - The JplDEFile instance to use.

Throws:

ArgumentException - Thrown when the file specified by the file is not a valid JplDE430 file.

ArgumentNullException - Thrown when file is null.

JplDE430

protected JplDE430(@Nonnull
                   JplDE430 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(JplDE 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 JplDE

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(JplDE430 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 JplDE430.checkForSameDefinition(agi.foundation.celestial.JplDE) method.

Overrides:

computeCurrentDefinitionHashCode in class JplDE

Returns:

The computed hash code.

getSource

public final String getSource()

Gets the string describing the source of the data.

getEarthRadius

public final double getEarthRadius()

Gets the radius of Earth in kilometers.

getMoonFixedFrame

@Nonnull
public final ReferenceFrame getMoonFixedFrame()

Uses the JplDE430 data to return the orientation and position of the Moon's principal axes of inertia to define a fixed frame. This is useful as a frame in which to describe the gravity of the Moon.

This uses the International Celestial Reference Frame from the Earth in the CentralBodiesFacet to define these axes.

Returns:

A ReferenceFrame representing the orientation and position of the Moon.

getMoonTopographicFixedFrame

@Nonnull
public final ReferenceFrame getMoonTopographicFixedFrame()

Uses the JplDE430 data to return the orientation and position of the Moon's "Mean Earth" axes which define a fixed frame with the z-axis pointing toward the mean axis of rotation, the x-axis pointing toward the mean direction to the Earth, and the y-axis orthogonal. This is useful for describing topographic features on the Moon.

This uses the International Celestial Reference Frame from the Earth in the CentralBodiesFacet to define these axes.

Returns:

A ReferenceFrame representing the orientation and position of the Moon.

getMoonLibrationModel

public final LibrationModel getMoonLibrationModel()

Gets a libration model for the Moon.

Specified by:

getMoonLibrationModel in interface IJplDEWithMoonLibrationModel

Returns:

A lunar libration model.