agi.foundation.ccsds

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

Class CcsdsOrbitEphemerisMessageFile

java.lang.Object

agi.foundation.compatibility.BaseCollection<T>

agi.foundation.infrastructure.DefinitionalObjectCollection<CcsdsOrbitEphemerisMessageSegment>

agi.foundation.ccsds.CcsdsOrbitEphemerisMessageFile

All Implemented Interfaces:

ICloneWithContext, IEnumerateDependencies, IEquatableDefinition, IFreezable, Iterable<CcsdsOrbitEphemerisMessageSegment>, Collection<CcsdsOrbitEphemerisMessageSegment>, List<CcsdsOrbitEphemerisMessageSegment>

public class CcsdsOrbitEphemerisMessageFile
extends DefinitionalObjectCollection<CcsdsOrbitEphemerisMessageSegment>

Reads from and writes to Orbit Ephemeris Message (OEM) files determined by the specifications of The Consultative Committee for Space Data Systems (CCSDS). CCSDS OEM files can express position, velocity, acceleration, and covariance information.

The CCSDS specifications can be found on the CCSDS website. The two supported formats for OEM files are Key-value notation (KVN) and extensible markup language (XML). The official recommended standards for KVN OEM files can be found in "Orbit Data Messages", Document CCSDS 502.0-B-2 on the above website. The official recommended standards for XML OEM files can be found in "XML Specifications for Navigation Data Messages", Document CCSDS 505.0-B-2 on the website. Both documents also contain a few useful examples of correctly formatted OEM files for their respective formats.

Each OEM file can contain several segments of ephemeris data, so this class mostly serves as a container for CcsdsOrbitEphemerisMessageSegment objects and as an interface for reading and writing those objects. The actual ephemeris and covariance data is stored in the segments.

Constructor Summary

Constructors

Modifier	Constructor and Description
	CcsdsOrbitEphemerisMessageFile() Initializes a new instance.
protected	CcsdsOrbitEphemerisMessageFile(CcsdsOrbitEphemerisMessageFile 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(CcsdsOrbitEphemerisMessageFile other) Checks to determine if another instance has the same definition as this instance and returns true if it does.
protected boolean	checkForSameDefinition(DefinitionalObjectCollection<CcsdsOrbitEphemerisMessageSegment> 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.
ArrayList<String>	getComments() Gets a collection containing comments from the header of a CCSDS OEM file.
GregorianDate	getCreationDate() Gets the file creation date and time in UTC.
String	getOriginator() Gets the creating agency or operator.
String	getVersion() Gets the ephemeris file version.
static CcsdsOrbitEphemerisMessageFile	readFrom(BufferedReader reader) Reads the CCSDS OEM file.
static CcsdsOrbitEphemerisMessageFile	readFrom(String filename) Reads the CCSDS OEM file.
void	setCreationDate(GregorianDate value) Sets the file creation date and time in UTC.
void	setOriginator(String value) Sets the creating agency or operator.
void	setVersion(String value) Sets the ephemeris file version.
void	writeTo(Writer writer) Writes this instance to a Writer in the CCSDS orbit ephemeris message OEM format.
void	writeTo(Writer writer, CcsdsOemFileWritingOptions options) Writes this instance to a Writer in the CCSDS orbit ephemeris message OEM format.

Methods inherited from class agi.foundation.infrastructure.DefinitionalObjectCollection

addRange, clearItems, enumerateDependencies, freeze, freezeAggregatedObjects, getDefinitionHashCode, getIsFrozen, insertItem, isSameDefinition, removeItem, setItem, throwIfFrozen

Methods inherited from class agi.foundation.compatibility.BaseCollection

add, add, addAll, addAll, clear, contains, containsAll, get, getItems, indexOf, isEmpty, iterator, lastIndexOf, listIterator, listIterator, remove, remove, removeAll, retainAll, set, size, subList, toArray, toArray

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.List

equals, hashCode, replaceAll, sort, spliterator

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream

Methods inherited from interface java.lang.Iterable

forEach

Constructor Detail

CcsdsOrbitEphemerisMessageFile

public CcsdsOrbitEphemerisMessageFile()

Initializes a new instance.

CcsdsOrbitEphemerisMessageFile

protected CcsdsOrbitEphemerisMessageFile(@Nonnull
                                         CcsdsOrbitEphemerisMessageFile 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

Overrides:

clone in class DefinitionalObjectCollection<CcsdsOrbitEphemerisMessageSegment>

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(DefinitionalObjectCollection<CcsdsOrbitEphemerisMessageSegment> other)

Description copied from class: DefinitionalObjectCollection

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).

Overrides:

checkForSameDefinition in class DefinitionalObjectCollection<CcsdsOrbitEphemerisMessageSegment>

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(@Nullable
                                         CcsdsOrbitEphemerisMessageFile 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 CcsdsOrbitEphemerisMessageFile.checkForSameDefinition(agi.foundation.infrastructure.DefinitionalObjectCollection<agi.foundation.ccsds.CcsdsOrbitEphemerisMessageSegment>) method.

Overrides:

computeCurrentDefinitionHashCode in class DefinitionalObjectCollection<CcsdsOrbitEphemerisMessageSegment>

Returns:

The computed hash code.

getVersion

public final String getVersion()

Gets the ephemeris file version.

setVersion

public final void setVersion(String value)

Sets the ephemeris file version.

getCreationDate

@Nonnull
public final GregorianDate getCreationDate()

Gets the file creation date and time in UTC.

setCreationDate

public final void setCreationDate(@Nonnull
                                  GregorianDate value)

Sets the file creation date and time in UTC.

getOriginator

public final String getOriginator()

Gets the creating agency or operator. The country of origin should also be provided where the originator is not a national space agency.

setOriginator

public final void setOriginator(String value)

Sets the creating agency or operator. The country of origin should also be provided where the originator is not a national space agency.

getComments

public final ArrayList<String> getComments()

Gets a collection containing comments from the header of a CCSDS OEM file.

readFrom

@Nonnull
public static CcsdsOrbitEphemerisMessageFile readFrom(@Nonnull
                                                                String filename)

Reads the CCSDS OEM file. If it can be parsed as a valid XML document, it will be. Otherwise, it will be parsed as a key-value notation (KVN) OEM file.

Parameters:

filename - The name of the CCSDS OEM file from which to read.

Returns:

A container for segments containing ephemeris and covariance data from the file.

Throws:

ArgumentNullException - Thrown if the filename is null.

readFrom

@Nonnull
public static CcsdsOrbitEphemerisMessageFile readFrom(@Nonnull
                                                                BufferedReader reader)

Reads the CCSDS OEM file. If it has a valid XML header, it will be parsed as an XML OEM file. Otherwise, it will be parsed as a key-value notation (KVN) OEM file.

Parameters:

reader - A reader for the CCSDS OEM file.

Returns:

A container for segments containing ephemeris and covariance data from the file.

Throws:

ArgumentNullException - Thrown if the reader is null.

writeTo

public final void writeTo(@Nonnull
                          Writer writer)

Writes this instance to a Writer in the CCSDS orbit ephemeris message OEM format.

This overload uses the DefaultOptions (get) of the CcsdsOemFileWritingOptions, which means that the CreationDate (get / set) is overridden by the current date and time and that the OEM will be written in the Key-Value Notation (KVN) format.

The Writer can be a OutputStreamWriter for writing to a file, a StringWriter for writing to a string, or any number of other types.

If acceleration information is contained in the EphemerisData (get / set) of any of the segments that this instance contains or the CovarianceData (get / set) of any of the segments is not null or empty, then the Version (get / set) needs to be set to 2.0 or this method will throw.

Parameters:

writer - The writer to which to write this instance.

writeTo

public final void writeTo(@Nonnull
                          Writer writer,
                          @Nonnull
                          CcsdsOemFileWritingOptions options)

Writes this instance to a Writer in the CCSDS orbit ephemeris message OEM format.

The Writer can be a OutputStreamWriter for writing to a file, a StringWriter for writing to a string, or any number of other types.

If acceleration information is contained in the EphemerisData (get / set) of any of the segments that this instance contains or the CovarianceData (get / set) of any of the segments is not null or empty, then the Version (get / set) needs to be set to 2.0 or this method will throw.

Parameters:

writer - The writer to which to write this instance.

options - The output choices that are used when writing this instance.

Throws:

ArgumentNullException - Thrown when the writer or options are null.

PropertyInvalidException - Thrown when any required property is null, when the Version (get / set) is not 1.0 or 2.0, or when acceleration or covariance information is available but the Version (get / set) is 1.0.