[SIS-166] Replace repetition of private getter/setters in CRS classes by @XmlElements annotation

• Type: Task
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.4, 0.5
• Fix Version/s: 0.6
• Component/s: Referencing
• Labels: JAXB
• Assignee: Martin Desruisseaux
• Reporter: Martin Desruisseaux
• Created: 19/Mar/14 20:48
• Updated: 12/Aug/22 10:05
• Resolved: 04/Sep/15 09:14

Description

Some CRS implementation classes in org.apache.sis.referencing.crs package contain many private getter and setter methods for coordinate system marshalling/unmarshalling with JAXB. For example DefaultEngineeringCRS has the following methods:

    /**
     * Invoked by JAXB at marshalling time.
     */
    @XmlElement(name="affineCS")      private AffineCS      getAffineCS()      {return getCoordinateSystem(AffineCS     .class);}
    @XmlElement(name="cartesianCS")   private CartesianCS   getCartesianCS()   {return getCoordinateSystem(CartesianCS  .class);}
    @XmlElement(name="cylindricalCS") private CylindricalCS getCylindricalCS() {return getCoordinateSystem(CylindricalCS.class);}
    @XmlElement(name="linearCS")      private LinearCS      getLinearCS()      {return getCoordinateSystem(LinearCS     .class);}
    @XmlElement(name="polarCS")       private PolarCS       getPolarCS()       {return getCoordinateSystem(PolarCS      .class);}
    @XmlElement(name="sphericalCS")   private SphericalCS   getSphericalCS()   {return getCoordinateSystem(SphericalCS  .class);}
    @XmlElement(name="userDefinedCS") private UserDefinedCS getUserDefinedCS() {return getCoordinateSystem(UserDefinedCS.class);}

    /**
     * Invoked by JAXB at unmarshalling time.
     */
    private void setAffineCS     (final AffineCS      cs) {super.setCoordinateSystem("affineCS",      cs);}
    private void setCartesianCS  (final CartesianCS   cs) {super.setCoordinateSystem("cartesianCS",   cs);}
    private void setCylindricalCS(final CylindricalCS cs) {super.setCoordinateSystem("cylindricalCS", cs);}
    private void setLinearCS     (final LinearCS      cs) {super.setCoordinateSystem("linearCS",      cs);}
    private void setPolarCS      (final PolarCS       cs) {super.setCoordinateSystem("polarCS",       cs);}
    private void setSphericalCS  (final SphericalCS   cs) {super.setCoordinateSystem("sphericalCS",   cs);}
    private void setUserDefinedCS(final UserDefinedCS cs) {super.setCoordinateSystem("userDefinedCS", cs);}

This is an ugly hack, since there is really only one coordinate system property, which may have different names in a GML document depending of its type. A more elegant solution would be to declare all the names in a single method, like below:

    /**
     * Returns the coordinate system.
     *
     * @return The coordinate system.
     */
    @Override
    @XmlElements({
      @XmlElement(name = "cartesianCS",   type = DefaultCartesianCS.class),
      @XmlElement(name = "affineCS",      type = DefaultAffineCS.class),
      @XmlElement(name = "cylindricalCS", type = DefaultCylindricalCS.class),
      @XmlElement(name = "linearCS",      type = DefaultLinearCS.class),
      @XmlElement(name = "polarCS",       type = DefaultPolarCS.class),
      @XmlElement(name = "sphericalCS",   type = DefaultSphericalCS.class),
      @XmlElement(name = "userDefinedCS", type = DefaultUserDefinedCS.class)
    })
    public CoordinateSystem getCoordinateSystem() {
        return super.getCoordinateSystem();
    }

    /**
     * Used by JAXB only (invoked by reflection).
     */
    private void setCoordinateSystem(final CoordinateSystem cs) {
        super.setCoordinateSystem("coordinateSystem", cs);
    }

However it didn't worked in our experiment. For a unknown reason, the unmarshalled coordinate system was empty. We need more investigation about this problem in order to replace the hack by the above-cited cleaner strategy.

Issue Links

• relates to: SIS-159 Complete JAXB annotations for CRS objects