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Admin : Page créée avec « == Goal == In this page, we give a relatively concrete example allowing to create an application with its own GUI
2017-12-21T12:45:34Z

Page créée avec « == Goal == In this page, we give a relatively concrete example allowing to create an application with its own <font color=#FF8C00 title="Graphical User Interface">GUI</fon... »

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== Goal ==
In this page, we give a relatively concrete example allowing to create an application with its own <font color=#FF8C00 title="Graphical User Interface">GUI</font> (using of couse [https://logiciels.cnes.fr/en/content/genius GENIUS] and <font color=#556B2F>'''GENOPUS'''</font>!) to propagate an orbit using [https://logiciels.cnes.fr/en/content/patrius PATRIUS].

Nevertheless, in order to simplify the example (else you may directly use [https://logiciels.cnes.fr/en/content/psimu PSIMU]!), we will "only" consider as inputs:
* '''Initial orbital parameters'''
* '''Vehicle characteristics''' (only dry mass and simple aerodynamic characteristics)
* Choice of '''force models'''
Only Balmino for Earth potential
Atmospheric models
In addition:
* Data will be stored in '''INI_suffix.xml''' files (or '''INIT.xml''' by default)
* Some results will be displayed on the <font color=#FF8C00 title="Graphical User Interface">GUI</font> console but also in a '''EPH_suffix.txt''' file ('''EPHEM.txt''' by default)

== Using GDataPanelAbstract to organize input data ==

To do it, we will have to create a class extending from <font color=#4169E1>GDataPanelAbstract</font> and adding [{{PathCurrentJavaDoc}}/fr/cnes/genopus/orbits/GPOrbit.html GPOrbit], [{{PathCurrentJavaDoc}}/fr/cnes/genopus/vehicle/GPVehicle.html GPVehicle] and [{{PathCurrentJavaDoc}}/fr/cnes/genopus/forces/GPForceModels.html GPForceModels] objects in different tabs.

<font color=#FF0000>''Note : be careful as GPOrbit extends from Gcontainer and not from GPanel, so it is mansatory to encapsulate it in a GPanel class (privalte class in our example.''</font>

<syntaxhighlight lang="java">
public class WidPropagatorDataPanel extends GDataPanelAbstract {

private final WidOrbit widOrbit;
private final GPVehicle widVehicle;
private final GPForceModels widForces;

/**
* Constructor.
* @throws GException GENIUS exception
*/
public WidPropagatorDataPanel() throws GException {

super("Data");

// Creating an orbit widget
widOrbit = new WidOrbit("Initial orbital parameters");

// Creating a vehicle widget (only with dry mass and simple aerodynamic properties)
widVehicle = new GPVehicle("Vehicle characteristics", true, false, true, false, false);

// Creating a force model widget (only with potential [Balmino] and atmosphere)
AttractionModelsEnum[] attractionModelsAvailable = { AttractionModelsEnum.BALMINO };
widForces = new GPForceModels("Models", AttractionModelsEnum.BALMINO, attractionModelsAvailable, false, true, false, false, false, false);

// Adding it in a tabbedpane
this.addTab("Orbit", widOrbit);
this.addTab("Vehicle", widVehicle);
this.addTab("Forces", widForces);
// Adding an output console
this.addConsoleTab("Console");

}

public void clear() throws GException {
// TODO Auto-generated method stub
}

/**
* Private class needed because GPOrbit is not a GPanel ...
*/
private class WidOrbit extends GPanel implements GReadWrite {

private final GPOrbit orbit;
public WidOrbit ( final String label) {
orbit = new GPOrbit(label);
}
public void display() throws GException { generic(); }
@Override
public void generic() throws GException { put(orbit); }
public void read() throws GException { generic(); }
public void write() throws GException { generic(); }
/**
* @return the GP orbit widget
*/
public GPOrbit getGPOrbit() {
return orbit;
}

}

/**
* Class to get the PATRIUS orbit object
* @return PATRIUS orbit object
* @throws GPOrbitException GENOPUS exception
*/
public Orbit getOrbit() throws GPOrbitException {
return widOrbit.getGPOrbit().getPatriusObject();
}

/**
* Class to get the Custom PATRIUS vehicle object
* @return the widVehicle
* @throws GPVehicleException GENOPUS exception
*/
public CustomVehicle getVehicle() throws GPVehicleException {
return widVehicle.getPatriusObject();
}

/**
* Class to get the Custom PATRIUS force models object
* @return Custom PATRIUS force models object
* @throws GException GENIUS exception
/
public CustomForceModels getForces() throws GException {
final Assembly assembly = getVehicle().getAssembly(FramesFactory.getCIRF());
return widForces.getPatriusObject(assembly);
}

}
</syntaxhighlight>

== Create the batch computation mode ==

The basic idea is to develop a class allowing to propagate an orbit and that will be called using the <font color=#4169E1>GJavaCommandLauncher</font> class. This class will include:
reading data in a file (a <font color=#FF8C00 title="Extensible Markup Language">XML</font> one automatically generated thanks to [https://logiciels.cnes.fr/en/content/genius GENIUS])
* using these data and considering other ones not exposed via the <font color=#FF8C00 title="Graphical User Interface">GUI</font> (in order to simplify the example) to build the numerical propagator:
Numerical integrator => <font color=#FF8C00>RungeKutta</font> 4th order with a 5s step
Propagation time => 1 orbit
** StepHandler = 60s
* propagating the orbit
* writing results on the screen and inside the '''EPHEM.txt''' file.

We may see on the following code inside the <font color=#4169E1>compute()</font> method how the [https://logiciels.cnes.fr/en/content/patrius PATRIUS] propagator is implemented as well as the associated stephandler in a specific private class.

<syntaxhighlight lang="java">
public class BatchPropagator {

/** Initial orbit */
private Orbit orbit;
/** Vehicle characteristics */
private CustomVehicle vehicle;
/** Forces */
private CustomForceModels forces;

/** UTC time scale */
private TimeScale UTC;

/** By default EPHEM file names */
private static final String EPH_FILE = "EPHEM.txt";

/**
* Constructor.
* @param nomFicData name of the context file.
* @param nomFicEphem name of the output file.
* @throws IOException GENIUS exception.
*/
public BatchPropagator (final String nomFicData, final String nomFicEphem) throws IOException {

// Patrius dataset initialization
try {
PatriusDataset.addResourcesFromPatriusDataset();
} catch (OrekitException err) {
GConsoleLogger.getLogger().log(Level.SEVERE, err.getMessage());
}

WidPropagatorDataPanel dataPan = null;
try {
dataPan = new WidPropagatorDataPanel();
} catch (GException err) {
GConsoleLogger.getLogger().log(Level.SEVERE, err.getMessage());
}
// Data read inside the XML file
try {
GFileManipulation.readConfig(nomFicData, "Propagator", dataPan, true);
} catch (GFileManipulatorException err) {
GConsoleLogger.getLogger().log(Level.SEVERE, err.getMessage());
}
// Orbit initialization
try {
orbit = dataPan.getOrbit();
} catch (GPOrbitException err) {
GConsoleLogger.getLogger().log(Level.SEVERE, err.getMessage());
}
// Vehicle initialization
try {
vehicle = dataPan.getVehicle();
} catch (GPVehicleException err) {
GConsoleLogger.getLogger().log(Level.SEVERE, err.getMessage());
}
// Forces initialization
try {
forces = dataPan.getForces();
} catch (GException err) {
GConsoleLogger.getLogger().log(Level.SEVERE, err.getMessage());
}

// Recovery of the UTC time scale using a "factory"
try {
UTC = TimeScalesFactory.getUTC();
} catch (OrekitException err) {
GConsoleLogger.getLogger().log(Level.SEVERE, err.getMessage());
}

}

/**
* Method to propagate
* @throws PropagationException PATRIUS exception
*/
public void compute() throws PropagationException {

// Getting the mas provider from the vehicle object.
final MassProvider mm = new MassModel(vehicle.getAssembly(FramesFactory.getCIRF()));

// We create a spacecratftstate
final SpacecraftState iniState = new SpacecraftState(orbit, mm);

// Initialization of the Runge Kutta integrator with a 5 s step
final double pasRk = 5.;
final FirstOrderIntegrator integrator = new ClassicalRungeKuttaIntegrator(pasRk);

// Initialization of the propagator
final NumericalPropagator propagator = new NumericalPropagator(integrator);
propagator.resetInitialState(iniState);

// Adding additional state
propagator.setMassProviderEquation(mm);

// Forcing integration using cartesian equations
propagator.setOrbitType(OrbitType.CARTESIAN);

// Adding an attitude law (in case of lift component)
final AttitudeLaw attitudeLaw = new LofOffset(LOFType.LVLH, RotationOrder.ZYX, 0., 0., 0.);
propagator.setAttitudeProvider(attitudeLaw);

// Adding force models
List<ForceModel> list = forces.getForceModelsList();
for (ForceModel forceModel : list) {
propagator.addForceModel(forceModel);
}

// Creation of a fixed step handler
final ArrayList<SpacecraftState> listOfStates = new ArrayList<SpacecraftState>();
OrekitFixedStepHandler myStepHandler = new OrekitFixedStepHandler() {
private static final long serialVersionUID = 1L;
public void init(SpacecraftState s0, AbsoluteDate t) {
// Nothing to do ...
}
public void handleStep(SpacecraftState currentState, boolean isLast)
throws PropagationException {
// Adding S/C to the list
listOfStates.add(currentState);
}
};
// The handler frequency is set to 60s
propagator.setMasterMode(60., myStepHandler);

// Propagating on 1 period
final double dt = orbit.getKeplerianPeriod();
final AbsoluteDate finalDate = orbit.getDate().shiftedBy(dt);
final SpacecraftState finalState = propagator.propagate(finalDate);
final Orbit finalOrbit = finalState.getOrbit();

// Printing new date and semi major axis
System.out.println();
System.out.println("Initial date = "+orbit.getDate().toString(UTC));
System.out.println("Initial semi major axis = "+orbit.getA()/1000.+" km");
System.out.println("New date = "+finalOrbit.getDate().toString(UTC));
System.out.println("Final semi major axis = "+finalOrbit.getA()/1000.+" km");

// Writing in the EPHEM.txt file
try {
System.out.println();
System.out.println("EPHEM.txt file writing ...");
FileWriter ephem = new FileWriter(new File(EPH_FILE));
Locale.setDefault(Locale.US);
for (SpacecraftState sc : listOfStates) {
ephem.write(String.format("%s %22.15e \n", sc.getDate(), sc.getA()/1000.));
}
ephem.close();
} catch (IOException err) {
GConsoleLogger.getLogger().log(Level.SEVERE, err.getMessage());
}

}

/**
* Main method ...
* @param args
*/
public static void main(String[] args) {

BatchPropagator batch;
try {
batch = new BatchPropagator("INIT.xml", "EPHEM.txt");
batch.compute();
} catch (IOException err) {
GConsoleLogger.getLogger().log(Level.SEVERE, err.getMessage());
} catch (PropagationException err) {
GConsoleLogger.getLogger().log(Level.SEVERE, err.getMessage());
}

}

}
</syntaxhighlight>

== Using GMainFrameAbstract for the main frame ==

Once the batch mode is available (see above), we have just to create the last third class extending from <font color=#4169E1>GMainFrameAbstract</font>, displaying data and allowing to execute the batch mode ...

<syntaxhighlight lang="java">
public class WidPropagator extends GMainFrameAbstract<WidPropagatorDataPanel> {

// FILE NAMES

/** Prefix for context file names */
private static final String INI_FILE_PREFIX = "INI_";
/** By default context file names */
private static final String INI_FILE = "INIT.xml";
/** Prefix for output file names */
private static final String EPH_FILE_PREFIX = "EPH_";
/** By default EPHEM file names */
private static final String EPH_FILE = "EPHEM.txt";

// SIZES

/** Data panel height */
private static final int DATAPANEL_HEIGHT = 400;
/** Error console height */
private static final int ERRCONSOLE_HEIGHT = 80;
/** Icon size */
private static final int ICON_SIZE = 12;

/**
* Constructor.
* @throws GException GENIUS exception
*/
public WidPropagator() throws GException {

super("Propagator",
new WidPropagatorDataPanel(),
new GContextFileManagement(".", "Propagator data", new GFileFilter(INI_FILE_PREFIX, ".xml", "Propagator Files") ),
new GAboutDialog("About S/W", "Propagator using PATRIUS ...", "CNES", "V1.0 ; 20/12/2017", null),
new GSaveResults("Saving results", new File("."), ".txt", ".xml"),
DATAPANEL_HEIGHT, ERRCONSOLE_HEIGHT, ICON_SIZE, false);

}

/**
* Method to manage saving data and results files
*/
@Override
protected void saveFilesManagement() throws GException {

final File ini = new File(INI_FILE);
final File res = new File(EPH_FILE);

// The context file INIT.xml will be saved in INI_....xml
this.getSaveResultsDialog().setContextFile(ini.getName(), INI_FILE_PREFIX, true);
// Result files consist in a single one named by default "EPHEM"
this.getSaveResultsDialog().clearResultFileList();
this.getSaveResultsDialog().addSingleResultFile(res.getName(), EPH_FILE_PREFIX, true);

this.getSaveResultsDialog().show();

}

/**
* Method to manage what to do before starting the computation
*/
@Override
protected void customPreProcessManagement() throws GFileManipulatorException {

// We write a context file with data coming from the data panel
GFileManipulation.writeConfig(INI_FILE, "Propagator", this.getDataPanel(), true);
// We initialize the JavaCommandLauncher
final String classPath = System.getProperty("java.class.path");
this.getJavaCommandLauncher().setJavaCommand(classPath, new String[] {"propagator.BatchPropagator"});
// We display the console above the other tabbedpanes
this.getDataPanel().selectConsoleTab();
}

/**
* Method to manage what to do after computation
*/
@Override
protected void customPostProcessManagement() {
// Nothing to do ...
}

/**
* Main method.
* @param args
* @throws GException
*/
public static void main(String[] args) throws GException {

// Patrius dataset initialization
try {
PatriusDataset.addResourcesFromPatriusDataset();
} catch (OrekitException err) {
err.printStackTrace();
}

final WidPropagator pan = new WidPropagator();
pan.displayMainFrame();

}
}

</syntaxhighlight>

== Final result ==

Now you are able to load this <font color=#FF8C00 title="Graphical User Interface">GUI</font> and to use it!

[[File:Propagator.jpg]]