agi.foundation.access.constraints

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

Class NavigationAccuracyAssessedConstraint

java.lang.Object

agi.foundation.infrastructure.DefinitionalObject

agi.foundation.access.AccessQuery

agi.foundation.access.AccessConstraint

agi.foundation.access.MinimumMaximumAccessConstraint

agi.foundation.access.constraints.NavigationAccuracyAssessedConstraint

All Implemented Interfaces:

ISingleObjectConstraint, ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable

public class NavigationAccuracyAssessedConstraint
extends MinimumMaximumAccessConstraint
implements ISingleObjectConstraint

An Access constraint which restricts access to the ConstrainedObject (get / set) to when the assessed navigation accuracy is above a minimum, below a maximum or both.

This constraint requires that the ConstrainedObject (get / set) provide IGpsReceiverService.

This constraint computes accuracy using the evaluator returned by GpsReceiver.getNavigationAccuracyAssessedEvaluator(agi.foundation.navigation.datareaders.PerformanceAssessmentFile).

Nested Class Summary

Nested classes/interfaces inherited from class agi.foundation.access.MinimumMaximumAccessConstraint

MinimumMaximumAccessConstraint.MinMaxThresholdEvaluator

Constructor Summary

Constructors

Modifier	Constructor and Description
	NavigationAccuracyAssessedConstraint() Initializes a new instance with default values.
	NavigationAccuracyAssessedConstraint(double maximumValue, NavigationAccuracyAssessedType valueToConstrain, PerformanceAssessmentFile paf) Initializes a new instance with the specified maximum value, accuracy value to constrain, and performance assessment file.
	NavigationAccuracyAssessedConstraint(IServiceProvider constrainedObject, double maximumValue, NavigationAccuracyAssessedType valueToConstrain, PerformanceAssessmentFile paf) Initializes a new instance with the specified constrained object, maximum value, accuracy value to constrain, and performance assessment file.
protected	NavigationAccuracyAssessedConstraint(NavigationAccuracyAssessedConstraint existingInstance, CopyContext context) Initializes a new instance as a copy of an existing instance.

Method Summary

Modifier and Type	Method and Description
void	buildQueryEvaluator(ConstraintQueryBuilder builder, EvaluatorGroup group) Builds a query evaluator from this constraint.
protected boolean	checkForSameDefinition(MinimumMaximumAccessConstraint other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(NavigationAccuracyAssessedConstraint 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.
AccuracyCalculationPersona	getCalculationPersona() Gets the calculation persona defining how the evaluator will react when it encounters no data for a given satellite during the accuracy calculation.
IServiceProvider	getConstrainedObject() Gets an object which provides the IGpsReceiverService to which this constraint applies.
Duration	getMaximumStepsize() Gets the maximum step size allowed for sampling this constraint.
PerformanceAssessmentFile	getPerformanceAssessmentFile() Gets the performance Assessment File (PAF) containing the ephemeris and clock errors for the GPS satellites over a period of time.
NavigationAccuracyAssessedType	getValueToConstrain() Gets the type of assessed accuracy to use for this constraint.
void	setCalculationPersona(AccuracyCalculationPersona value) Sets the calculation persona defining how the evaluator will react when it encounters no data for a given satellite during the accuracy calculation.
void	setConstrainedObject(IServiceProvider value) Sets an object which provides the IGpsReceiverService to which this constraint applies.
void	setMaximumStepsize(Duration value) Sets the maximum step size allowed for sampling this constraint.
void	setPerformanceAssessmentFile(PerformanceAssessmentFile value) Sets the performance Assessment File (PAF) containing the ephemeris and clock errors for the GPS satellites over a period of time.
void	setValueToConstrain(NavigationAccuracyAssessedType value) Sets the type of assessed accuracy to use for this constraint.
String	toString() Returns a string representation of the object.

Methods inherited from class agi.foundation.access.MinimumMaximumAccessConstraint

checkForSameDefinition, getIsMaximumEnabled, getIsMinimumEnabled, getMaximumTolerance, getMaximumValue, getMinimumTolerance, getMinimumValue, setIsMaximumEnabled, setIsMinimumEnabled, setMaximumTolerance, setMaximumValue, setMinimumTolerance, setMinimumValue

Methods inherited from class agi.foundation.access.AccessConstraint

checkForSameDefinition, freezeAggregatedObjects, getApplicability, getEvaluationOrder, getEvaluator, getSampling, setApplicability, setEvaluationOrder, toDisjunctiveNormalForm

Methods inherited from class agi.foundation.access.AccessQuery

and, and, anyPath, anyPath, anyPath, anyPath, anyPath, anyPath, atLeastN, atMostN, checkForSameDefinition, exactlyN, fromObject, fromObjectAllowNoConstraints, getDebuggingLogger, getEvaluator, getEvaluator, not, or, or, setDebuggingLogger

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, wait, wait, wait

Constructor Detail

NavigationAccuracyAssessedConstraint

public NavigationAccuracyAssessedConstraint()

Initializes a new instance with default values.

Before evaluating this constraint using AccessComputation, the user must set the PerformanceAssessmentFile (get / set) property and the MinimumValue (get / set) property, the MaximumValue (get / set) property, or both. Setting the ValueToConstrain (get / set) property as well is highly recommended. Before evaluating this constraint as part of an AccessQuery, it is also necessary to set the ConstrainedObject (get / set) property.

NavigationAccuracyAssessedConstraint

public NavigationAccuracyAssessedConstraint(double maximumValue,
                                            @Nonnull
                                            NavigationAccuracyAssessedType valueToConstrain,
                                            PerformanceAssessmentFile paf)

Initializes a new instance with the specified maximum value, accuracy value to constrain, and performance assessment file.

This constraint is ready for use with AccessComputation after being constructed using this constructor. However, before evaluating this constraint as part of an AccessQuery, it is necessary to set the ConstrainedObject (get / set) property.

Parameters:

maximumValue - Maximum allowable accuracy value.

valueToConstrain - The type of accuracy to compute.

paf - The performance assessment file containing the ephemeris and clock errors for the GPS constellation.

NavigationAccuracyAssessedConstraint

public NavigationAccuracyAssessedConstraint(IServiceProvider constrainedObject,
                                            double maximumValue,
                                            @Nonnull
                                            NavigationAccuracyAssessedType valueToConstrain,
                                            PerformanceAssessmentFile paf)

Initializes a new instance with the specified constrained object, maximum value, accuracy value to constrain, and performance assessment file.

This constraint is ready for use with both AccessComputation and AccessQuery after being constructed using this constructor.

Parameters:

constrainedObject - The object to which this constraint is applied.

maximumValue - Maximum allowable accuracy value.

valueToConstrain - The type of accuracy to compute.

paf - The performance assessment file containing the ephemeris and clock errors for the GPS constellation.

NavigationAccuracyAssessedConstraint

protected NavigationAccuracyAssessedConstraint(@Nonnull
                                               NavigationAccuracyAssessedConstraint 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(MinimumMaximumAccessConstraint 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 MinimumMaximumAccessConstraint

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(NavigationAccuracyAssessedConstraint 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 NavigationAccuracyAssessedConstraint.checkForSameDefinition(agi.foundation.access.MinimumMaximumAccessConstraint) method.

Overrides:

computeCurrentDefinitionHashCode in class MinimumMaximumAccessConstraint

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 AccessConstraint

Parameters:

enumerator - The enumerator that is informed of the dependencies of this object.

getConstrainedObject

public final IServiceProvider getConstrainedObject()

Gets an object which provides the IGpsReceiverService to which this constraint applies. It is not necessary to set this property when using this constraint with AccessComputation.

Specified by:

getConstrainedObject in interface ISingleObjectConstraint

setConstrainedObject

public final void setConstrainedObject(IServiceProvider value)

Sets an object which provides the IGpsReceiverService to which this constraint applies. It is not necessary to set this property when using this constraint with AccessComputation.

Specified by:

setConstrainedObject in interface ISingleObjectConstraint

getValueToConstrain

@Nonnull
public final NavigationAccuracyAssessedType getValueToConstrain()

Gets the type of assessed accuracy to use for this constraint.

setValueToConstrain

public final void setValueToConstrain(@Nonnull
                                      NavigationAccuracyAssessedType value)

Sets the type of assessed accuracy to use for this constraint.

getPerformanceAssessmentFile

public final PerformanceAssessmentFile getPerformanceAssessmentFile()

Gets the performance Assessment File (PAF) containing the ephemeris and clock errors for the GPS satellites over a period of time.

setPerformanceAssessmentFile

public final void setPerformanceAssessmentFile(PerformanceAssessmentFile value)

Sets the performance Assessment File (PAF) containing the ephemeris and clock errors for the GPS satellites over a period of time.

getCalculationPersona

@Nonnull
public final AccuracyCalculationPersona getCalculationPersona()

Gets the calculation persona defining how the evaluator will react when it encounters no data for a given satellite during the accuracy calculation.

By default, this is AccuracyCalculationPersona.DILIGENT

setCalculationPersona

public final void setCalculationPersona(@Nonnull
                                        AccuracyCalculationPersona value)

Sets the calculation persona defining how the evaluator will react when it encounters no data for a given satellite during the accuracy calculation.

By default, this is AccuracyCalculationPersona.DILIGENT

getMaximumStepsize

@Nonnull
public final Duration getMaximumStepsize()

Gets the maximum step size allowed for sampling this constraint. By default, this is 60 seconds.

In most cases, constraints use relative motion or derivative information to provide intelligent sampling. In the case of navigation constraints, the functions are highly discontinuous as navigation satellites come in and out of view. So, this step size represents the largest time interval which may be overlooked by the sampling. In other words, if the max step is 60 seconds, access may miss an interval less than 60 seconds in duration if the function jumps without any indication of a boundary crossing into or leaving the interval. If two steps are on opposite sides of the boundary, the constraint will subsample to find the exact time.

setMaximumStepsize

public final void setMaximumStepsize(@Nonnull
                                     Duration value)

Sets the maximum step size allowed for sampling this constraint. By default, this is 60 seconds.

In most cases, constraints use relative motion or derivative information to provide intelligent sampling. In the case of navigation constraints, the functions are highly discontinuous as navigation satellites come in and out of view. So, this step size represents the largest time interval which may be overlooked by the sampling. In other words, if the max step is 60 seconds, access may miss an interval less than 60 seconds in duration if the function jumps without any indication of a boundary crossing into or leaving the interval. If two steps are on opposite sides of the boundary, the constraint will subsample to find the exact time.

toString

public String toString()

Description copied from class: java.lang.Object

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())
 

Overrides:

toString in class Object

Returns:

a string representation of the object.

buildQueryEvaluator

public void buildQueryEvaluator(ConstraintQueryBuilder builder,
                                EvaluatorGroup group)

Builds a query evaluator from this constraint.

Specified by:

buildQueryEvaluator in class AccessConstraint

Parameters:

builder - The builder instance to use to build the evaluator.

group - The evaluator group in which to create individual constraint function evaluators.