agi.foundation.platforms

(agi.foundation.platforms-2024r3.jar)

Class PlatformLocationPoint

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.geometry.Point

agi.foundation.platforms.PlatformLocationPoint

All Implemented Interfaces:

ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable, IServiceProvider

public class PlatformLocationPoint
extends Point

A Point that can be used to refer to the current LocationPoint (get / set) of a Platform, whatever it is at the time that this point is evaluated. All method and properties on this class simply pass the call to the platform's current LocationPoint (get / set).

This class is helpful when you have other classes that depend on a platform's LocationPoint (get / set) and you want to be able to change the platform's point without updating the references in the other classes. Consider a platform configured like this:

EarthCentralBody earth = CentralBodiesFacet.getFromContext().getEarth();
Platform platform = new Platform();
platform.setLocationPoint(new PointCartographic(earth, Cartographic.getZero()));
platform.setOrientationAxes(new AxesNorthEastDown(earth, platform.getLocationPoint()));

If you later assign the LocationPoint (get / set) property with a new Point instance, you must also remember to update the axes referred to by the OrientationAxes (get / set) property to refer to the new Point instance. Now, consider a platform configured like this:

EarthCentralBody earth = CentralBodiesFacet.getFromContext().getEarth();
Platform platform = new Platform();
platform.setLocationPoint(new PointCartographic(earth, Cartographic.getZero()));
PlatformLocationPoint point = new PlatformLocationPoint(platform);
platform.setOrientationAxes(new AxesNorthEastDown(earth, point));

In this case, you can change the LocationPoint (get / set) property at will without worrying about the OrientationAxes (get / set) at all.

Constructor Summary

Constructors

Modifier	Constructor and Description
	PlatformLocationPoint(Platform platform) Creates a new instance of this class with the specified parameters
protected	PlatformLocationPoint(PlatformLocationPoint 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(PlatformLocationPoint other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(Point 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.
PointEvaluator	getEvaluator(EvaluatorGroup group) Gets an evaluator that can be used to find the motion of this point in its parent reference frame at a given date.
Platform	getPlatform() Gets the Platform whose LocationPoint (get / set) will receive all method calls.
void	setPlatform(Platform value) Sets the Platform whose LocationPoint (get / set) will receive all method calls.

Methods inherited from class agi.foundation.geometry.Point

checkForSameDefinition, createVectorAcceleration, createVectorDerivative, createVectorVelocity, getEvaluator, getRoot, getScalarElement, getScalarElement, getService

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

PlatformLocationPoint

public PlatformLocationPoint(Platform platform)

Creates a new instance of this class with the specified parameters

Parameters:

platform - The Platform whose LocationPoint (get / set) will receive all method calls.

PlatformLocationPoint

protected PlatformLocationPoint(@Nonnull
                                PlatformLocationPoint 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(Point 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 Point

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(PlatformLocationPoint 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 PlatformLocationPoint.checkForSameDefinition(agi.foundation.geometry.Point) method.

Overrides:

computeCurrentDefinitionHashCode in class Point

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.

getPlatform

public final Platform getPlatform()

Gets the Platform whose LocationPoint (get / set) will receive all method calls.

setPlatform

public final void setPlatform(Platform value)

Sets the Platform whose LocationPoint (get / set) will receive all method calls.

getEvaluator

public PointEvaluator getEvaluator(EvaluatorGroup group)

Gets an evaluator that can be used to find the motion of this point in its parent reference frame at a given date. Consider using the methods of GeometryTransformer instead of calling this method directly.

Specified by:

getEvaluator in class Point

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 Point.

Throws:

ArgumentNullException - Thrown if group is null.

PropertyInvalidException - Thrown if Platform (get / set) is null, or if Platform (get / set) has a null LocationPoint (get / set).