How to use

specialize

method

in

org.apache.sis.referencing.operation.DefaultConversion

/**
 * Creates the conversion instance to associate with this {@code AbstractDerivedCRS}.
 *
 * <p><b>WARNING:</b> this method is invoked at construction time and will invoke indirectly
 * (through {@link DefaultConversion}) the {@link #getCoordinateSystem()} method on {@code this}.
 * Consequently this method shall be invoked only after the construction of this {@code AbstractDerivedCRS}
 * instance is advanced enough for allowing the {@code getCoordinateSystem()} method to execute.
 * Subclasses may consider to make the {@code getCoordinateSystem()} method final for better guarantees.</p>
 */
private C createConversionFromBase(final Map<String,?> properties, final SingleCRS baseCRS, final Conversion conversion) {
  MathTransformFactory factory = null;
  if (properties != null) {
    factory = (MathTransformFactory) properties.get(ReferencingServices.MT_FACTORY);
  }
  if (factory == null) {
    factory = DefaultFactories.forBuildin(MathTransformFactory.class);
  }
  try {
    return DefaultConversion.castOrCopy(conversion).specialize(getConversionType(), baseCRS, this, factory);
  } catch (FactoryException e) {
    throw new IllegalArgumentException(Errors.getResources(properties).getString(
        Errors.Keys.IllegalArgumentValue_2, "conversion", conversion.getName()), e);
  }
}

/**
 * Creates the conversion instance to associate with this {@code AbstractDerivedCRS}.
 *
 * <p><b>WARNING:</b> this method is invoked at construction time and will invoke indirectly
 * (through {@link DefaultConversion}) the {@link #getCoordinateSystem()} method on {@code this}.
 * Consequently this method shall be invoked only after the construction of this {@code AbstractDerivedCRS}
 * instance is advanced enough for allowing the {@code getCoordinateSystem()} method to execute.
 * Subclasses may consider to make the {@code getCoordinateSystem()} method final for better guarantees.</p>
 */
private C createConversionFromBase(final Map<String,?> properties, final SingleCRS baseCRS, final Conversion conversion) {
  MathTransformFactory factory = null;
  if (properties != null) {
    factory = (MathTransformFactory) properties.get(ReferencingServices.MT_FACTORY);
  }
  if (factory == null) {
    factory = DefaultFactories.forBuildin(MathTransformFactory.class);
  }
  try {
    return DefaultConversion.castOrCopy(conversion).specialize(getConversionType(), baseCRS, this, factory);
  } catch (FactoryException e) {
    throw new IllegalArgumentException(Errors.getResources(properties).getString(
        Errors.Keys.IllegalArgumentValue_2, "conversion", conversion.getName()), e);
  }
}

/**
 * Ensures that {@link DefaultConversion#specialize DefaultConversion.specialize(…)} verifies the datum.
 *
 * @throws FactoryException if an error occurred while creating the conversion.
 */
@Test
public void testDatumCheck() throws FactoryException {
  final MathTransformFactory factory = DefaultFactories.forBuildin(MathTransformFactory.class);
  final DefaultConversion op = createLongitudeRotation(true);
  try {
    op.specialize(Conversion.class, HardCodedCRS.WGS84, HardCodedCRS.NTF_NORMALIZED_AXES, factory);
    fail("Should not have accepted to change the geodetic datum.");
  } catch (IllegalArgumentException e) {
    final String message = e.getMessage();
    assertTrue(message, message.contains("sourceCRS"));
    assertTrue(message, message.contains("Nouvelle Triangulation Française"));
  }
  try {
    op.specialize(Conversion.class, HardCodedCRS.NTF_NORMALIZED_AXES, HardCodedCRS.WGS84, factory);
    fail("Should not have accepted to change the geodetic datum.");
  } catch (IllegalArgumentException e) {
    final String message = e.getMessage();
    assertTrue(message, message.contains("targetCRS"));
    assertTrue(message, message.contains("Nouvelle Triangulation Française"));
  }
}

assertSame(op, op.specialize(Conversion.class, op.getSourceCRS(), op.getTargetCRS(), factory));
op = op.specialize(DefaultConversion.class, op.getSourceCRS(),
    changeCS(op.getTargetCRS(), HardCodedCS.GEODETIC_φλ), factory);
assertMatrixEquals("Longitude rotation of a two-dimensional CRS", Matrices.create(3, 4, new double[] {

    0, 0, 0, 1), MathTransforms.getMatrix(op.getMathTransform()), STRICT);
op = op.specialize(
    DefaultConversion.class,    // In normal use, this would be 'Conversion.class'.

final DefaultConversion completed = definingConversion.specialize(
    DefaultConversion.class,    // In normal use, this would be 'Conversion.class'.
    changeCS(reference.getSourceCRS(), HardCodedCS.GEODETIC_φλ),